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HD Radio™ Data Network Requirements

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1. 52 Table 17 Service Mode MP1 12E TCP Data Frame Structure SPS1 at 48 kb s onbe 53 Table 18 Service Mode MP2 I2E TCP Data Frame Structure SPS1 at 12 kb s on P3 54 Table 19 Service Mode MP2 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 55 Table 20 Service Mode MP2 I2E TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 56 Table 21 Service Mode MP3 I2E TCP Data Frame Structure SPS1 at 24 kb s on P3 57 Table 22 Service Mode MP3 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 58 Table 23 Service Mode MP3 I2E TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 59 Table 24 Service Mode MP1 E2X UDP Data Frame Structure P1 PID 60 Table 25 Service Mode MP2 E2X UDP Data Frame Structure P1 P3 PID 61 Table 26 Service Mode MP3 E2X UDP Data Frame Structure P1 P3 PID 62 Table 27 Service Mode MP1 E2X TCP Data Frame Structure P1 PID 63 Table 28 Service Mode MP2 E2X TCP Data Frame Structure P1 P3 PID 64 Table 29 Service Mode MP3 E2X TCP Data Frame Structure P1 P3 PID 65 Doc No TX
2. 20 42 2 Gilena Tor SWIGCh EH L sios mu lia ta O i pa a 22 AS SWICK CONnNguUrat O EE 23 4 3 1 Configuring Virtual Local Area Networks VLANS nana aaaaa nana aaa aaa aaa aaa 23 49 2 MOMONDO FONS arar tdi drid 23 4 3 3 Spanning Tree Protocol 77 77 23 4 3 4 Trunking E aifoj el rrmm 77 gt gt 24 4 3 5 Speed and Duplex Negotiation aa aaa 24 4 3 6 Limiting Other Extraneous Tratt 24 5 SPEATESE AND WAN LINKS E 26 5 1 STL Solutions for Data Transport and IBOC Applications 26 5 1 1 Adding Ethernet to a 950 MHZ STL System 26 5 1 21 Payload capabilities of a 950 MHZ STL System 27 5 1 2 Creating a LAN WAN Extension to the Transmitter Site 27 513 Td SILESL System for Data Transpo ea annia u au SO u SO Au alas u 29 SE Payload Capabilities of a T1 System 30 5 1 4 T1 E1 on a 5 8 GHz Bidirectional Radio Link 30 Akos IGOPUII ml zu aa
3. 11 2 3 Dual Importer to Exciter Split Configuration 13 3 I2E AND E2X NETWORK MESSAGE STRUCTURE _ 14 3 CANAS ol mu i 14 3 2 Message Structure Overview a aaa aaa aaa aaa aaa aaa 14 3 39 Importerto Exponer IZE WEE 15 3 3 1 MP1 I2E UDP Data Frame Structure ooccccccoccncccconnncoconcnnnnonnnnnnnnnnnnononnnnononnnnnnnnnnnnonanennonenens 15 3 3 2 MP212E UDP Data Frame Structure eied e Eae aa 15 30 9 MP3 ZE UDP Data Frame Stud 16 Jais TCP Hnplememnialiool ee a a ula i leaned V a L i ks 16 3 4 EXpOrer EE E2X uu ti iai ia si a a a i i a AAA 17 3 4 1 MP1 E2X UDP Data Frame Structure uu uuu Lu uyu unu uu aaa aa saaa aaa 17 342 MP2 E2X UDP Data Frame Structure gue eege u aaa a aaa geed secede uses 17 34 3 MP3 E2X UDP Data Frame Structure cic cicicadecetoceiancedeadedncattisicetecdavar iaa 17 3 4 4 TCP Implementation of I2E and E2X 18 4 NETWORKING TOPOLOGIES AND STRATEGIES 19 41 ADLAN Ee ege ELE 19 422 SWIC Wlan ena LOM siai ais un i i i K k i ki i i a i i a Duss 20 4 2 1 A Review of Hubs Switches and Routers
4. _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ _______ ____ ___ __ ________ _ _ ___ _ _ __ _ ___________ _ __________ __ _________________ _ _ Doc No TX_TN_2040 Page 50 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 15 Service Mode MP1 I2E TCP Data Frame Structure SPS1 at 12 kb s on P1 MP1 I2E TCP Data Frame SPS1 at 12 kb s on P1 E gt I P1 REQ 94 E gt I ACK 198 Doc No TX_TN_2040 Page 51 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 16 Service Mode MP1 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 MP1 I2E TCP Data Frame SPS1 at 32 kb s on P1 E gt l P1 REQ 94 Doc No TX_TN_2040 Page 52 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 17 Service Mode MP1 GE TCP Data Frame Structure SPS1 at 48 kb s on P1 MP1 I2E TCP Data Frame SPS1 at 48 kb s on P1 E gt l P1 REQ 64 E gt I ACK 460 Doc No TX TN 2040 Page 53 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 18 Service Mode MP2 GE TCP Data Frame Structure SPS1 at 12 kb s on P3 MP2 I2E TCP Data Frame SPS1 at 12 kb s on P3 E gt I P1 REQ 94 E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ 94 94 94 94 94 94 94 94 I E P3 ACK I E P3 ACK I E P3 ACK I gt E P3 ACK I E P3 ACK LE P3 ACK I E P3 ACK I E
5. P1 Table 28 Service Mode MP2 E2X TCP Data Frame Structure P1 P3 Table 29 Service Mode MP3 E2X TCP Data Frame Structure P1 P3 Doc No TX_TN_ 2040 Page 18 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 4 Networking Topologies and Strategies 4 1 HD LAN Configurations All HD Radio devices Importer Exporter and Exciter should use statically assigned IP addresses within their own subnet This subnet must be separate from the rest of the facility through the use of VLANs or physically separated networks The only way to be sure that no extraneous traffic is traversing the STL link is to place the entire HD Radio system on its own IP subnet It is imperative that we separate traffic traveling across the link from the production and office networks as this saves the link from having to carry broadcast or multicast traffic from the production network Figure 6 shows a recommended network deployment of subnetting using VLANs This recommendation should be followed without exception CORRECT P Network H Studio Transmitter Corporate VLAN Program Automation VLAN HD Radio VLAN May Reside in Either Subnet N V Lf mporter Exporter Figure 6 Recommended network deployment The Exciter will always be within the WAN subnet In the I2E configuration the Importer may be placed on either side of the subnet boundary in the E2X configuration the
6. Table 28 Service Mode MP2 E2X TCP Data Frame Structure P1 P3 PIDS MP2 E2X TCP Data Frame P1 P3 PIDS P1 ACK 420 P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK 64 64 64 64 64 64 64 64 PIDS ACK PIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACK PIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACK PIDS ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 en Doc No TX_TN_2040 Page 64 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 29 Service Mode MP3 E2X TCP Data Frame Structure P1 P3 PIDS MP3 E2X TCP Data Frame P1 P3 PIDS P1 ACK 420 P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK P3 ACK 60 60 60 60 60 60 60 60 PIDS ACK PIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACK PIDS ACKIPIDS ACKIPIDS ACKJPIDS ACKIPIDS ACK PIDS ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 k ww gt ___ Doc No TX TN 2040 Page 65 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requiremen
7. Zemxtdo ct 21231 New High Water PDUs 1 in fifo gt 2 Pa PS t t t t t t t gt t ta t ER Lal Lac LI L Figure 17 Log showing Exporter receive buffer status The numbers at the far right in Figure 17 show the level of buffering of the 20 frame rate P1 PDUS indicated with the notation PDUs 1 In this instance the buffers were depleted from 21 to 17 and then recovered indicating that this network may have some issues but is working adequately It P3 PDUs for MP2 and MP3 were operating they would be at the block pair rate of 8 per frame or 168 PDUs in the buffer In this case you would see PDUs 3 in fifo gt 168 counting up or down in addition to the PDUs 1 in fifo gt 20 for every eight 8 P3 PDUs Doc No TX TN 2040 Page 66 Rev 09 6 3 AAS AES EBU ALFN iBiguity Digital Corporation HD Radio Data Network Requirements Abbreviations Advanced Applications Services Audio Engineering Society European Broadcast Union Absolute L1 Frame Layer Address Resolution Protocol Bit Error Rate bits per second bytes per second 64 kb s unit of transmission bandwidth Twenty four DSOs in 193 bit frame transmitted at 1 544 Mbps Also known as T1 Digital Subscriber Line Dynamic Trunking Protocol Exporter to Exciter Exgine Protocol Exciter Engine Frequency Shift Keying Generation 1 Exciter Exporter only Generation 2 Excit
8. April 18 2005 Reference 4 In most cases the STL is the only full time link between the studio and the transmitter site Many of these transmitter sites are located in remote areas far removed from any high speed network access It is only natural that the STL be used to provide access to this site Possible STL solutions for data transport are e Add Ethernet capability to a 950 MHz STL e Create a separate data link e Data transport capabilities of a T1 STL TSL 5 1 1 Adding Ethernet to a 950 MHz STL System In areas where line of site exists the 950 MHz RF STL system is the de facto standard for radio station program audio transport The 950 MHz STL as its name implies is a one way microwave radio device which in the analog world was designed to convey a single stereo program to the transmitter site for over the air broadcast Digital STL systems brought with them the ability to multiplex one or more additional services and transport them over a single link In a digital STL system adding additional outbound services such as serial RS 232 data channels Ethernet connectivity and additional audio channels is possible up to the available bandwidth in the STL channel In some cases simple one way data circuits to the transmitter may be sufficient as shown in Figure 11 Ethernet UDP RS 232 950 MHz STL with Ethernet capability transports AES digital audio RS 232 and UDP Ethernet data and supports IBOC Figure 11 A 950 M
9. July 2006 2 MTM Technologies HD Radio Networking Implementation Recommendations Author Kurt VanderSluis Date July 2006 3 Biquity Digital Corporation MTM Technologies Network Field Assessment Observations and Results Authors Timothy Anderson amp Kurt VanderSluis Date August 2006 4 Moseley Associates Inc New STL TSL Solutions for LAN WAN Extension to Transmitter sites Author Bill Gould Date April 18 2005 5 Moseley Associates Hitless Space Diversity STL Enables IP Audio in Narrow STL Bands Author Howard Friedenberg Date April 2005 6 Accunet T1 5 Service Description and Interface Specification ATT Director NSD Business Special Services 1990 7 Synch10Mhz Remote Clock Synchronizer Reference Design Application Note Author Brian Kroeger iBiquity Digital Corp iBiquity Document TX TN 5089 2006 Doc No TX TN 2040 Page 69 Rev 09
10. Layer Function r E FE Network process to Application application Data Media Fath determination and e Packets Routers Network EE Figure 8 The Seven Layer OSI Networking Model Hubs operate only at Layer 1 the Physical Layer acting as repeaters or signal regenerators lt is a shared medium For example in a 16 port hub packets sent from Workstation 1 will be repeated sent to all remaining ports 2 16 Only one workstation can speak at a time Should two workstations seize the line at the same time a collision will occur and each will back off for a random amount of time and retransmit Switches may operate at Layer 2 the Data Link Layer They have the ability to see into the source and destination MAC address Each switch listens on every port after receiving each packet the switch updates its forwarding table with the source MAC address and the port on which the packet was received Then the switch builds a forwarding table referencing each MAC address to its specific switch port number Traffic that is destined for a particular computer is sent only to that computer Such switches are used to extend VLANs from the Layer 3 routers and switches via port trunks Routers and some switches operate at Layer 3 the Network Layer A Layer 3 Router looks at the destination IP address and consults the routing table for a matching subnet route and forwards the packet onto the appropriate interfaces
11. Exporter The clock message is sent as a synchronization counter in each block When Exgine has counted 16 clock messages a line is toggeled to the DUC to infer a 10 MHz clock At the starting boundary of each frame in Block Zero 0 the Exporter sends the frame rate P1 PDU the block rate PIDS and clock message PDUs along with the block pair rate P2 and or P3 message PDUs if they are configured The PIDS and clock messages are sent in each of the 15 subsequent blocks while the P3 messages are sent in each of the subsequent block pairs The bandwidth required for each mode depends on the logical channels configured and is independent of the Importer s service configuration within the mode MP1 frames are always 22 232 bytes an MP2 frame is always 24 536 bytes and an MP3 frame is always 27 736 bytes regardless of how the Importer is configured or if it is even connected 3 4 1 MP1 E2X UDP Data Frame Structure In MP1 mode only the P1 channel is used which affords a total of 96 kb s to both the MPS and any supplementary services that are configured Only the P1 logical channel PIDS and the clock are sent The E2X frame size is 22 232 bytes for an average data rate of 120 kb s See the following table in the Appendix Table 24 Service Mode MP1 E2X UDP Data Frame Structure P1 3 4 2 MP2 E2X UDP Data Frame Structure In MP2 mode logical channels P1 P3 and PIDS are used P3 adds an additional available bandwidth of 12 kb s whi
12. Exporter may be placed on either side of the subnet boundary Except for equipment that may be necessary to build the infrastructure that is routers and switches no other station equipment should be allowed in the WAN link subnet It is imperative that broadcast multicast and other extraneous traffic be kept off of the network path to the transmitter site and that the number of switches in the network path is minimized The implementation of VLANS or connection of devices through a dedicated physical network will substantially reduce packet loss and data collisions Figure 7 shows an improper network deployment INCORRECT Network O A Studio Transmitter Deploymeni Station LAN Export fd E En Zeg Se e La I lt IR Figure 7 Improper network deployment For more detailed information on networking topologies please refer to Figure 15 Figure 16 as well as References 1 and 2 Doc No TX_TN_2040 Page 19 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 4 2 Switch Implementation 4 2 1 A Review of Hubs Switches and Routers Hubs switches and routers form the backbone of any packet switched network These devices direct and manage the flow of data between all of the different connected devices on the network Hubs switches and routers work in the bottom three layers of the Open Systems Interconnection OSI Reference Model as shown in Figure 8 Data unit Devices
13. For more information see Reference 1 Example Provisioning Calculation HD Data stream MP1 I2E SPS1 TCP 56 kb s Management traffic 43 kb s VNC 40 kb s Telnet 3 kb s Broadcast and Multicast 1 kb s Other traffic 0 Total Traffic 56 43 1 100 kb s 100 kb s 60 of Minimum Provisioning Minimum Provisioning 5 3 x 100 kb s 167 kb s Additional bandwidth beyond the recommended guideline allows operation under poorer conditions but with diminishing returns In general bandwidth should not be used to adjust for a poor network Most WAN links configure bandwidth in DSO increments of 64 kb s blocks thus in the above example one would configure their WAN STL as a 3DSO for 192 kb s For specific provisioning requirements of each mode and service refer to Table 4 in Appendix A 5 3 2 1 Burst Rate Consideration The bulk of the HD Radio frame is sent in an initial burst at the beginning of the frame This initial burst can contain nearly 20 000 bytes and can be sent at near wire speed in the case of a 10 megabit per second connection On a 100 megabit per second connection the data would be sent as fast as the device can send usually in the vicinity of 40 megabits per second This burst must pass through the WAN link which is usually much slower than the burst transmission speed Each IP packet will contain approximately 1500 bytes of data so approximately 13 full size Ethernet frames are required to send the d
14. aaa aaa aaa aaa aaa aaa aaa aaa aaa aaa aaa aaa aaa aa aaa aaa 20 Figure 9 Typical studio switch and router deployment a aa saaa aaa asas aaa aaa aaa aaa aaa aaa aaa aaa aaa 21 Figure T0 Transmiter ste AEPDIOYM Ni i ai i ia ai a i i i i i i k e i a i i o o 21 Figure 1124 950 MAZ STL System With BEF E Lake ste uuu A E 26 Figure 12 950 MHz STL with 900 MHz LAN Extender Data Link ooocccccnnncccccnncoocoononoccnnnnnnnnnnnnnonnnnnnnnnnnnnnnnnnnnnnonornnnnnnnnncnnnnnnnnnnnos 28 Figure 13 Block diagram of a T1 STL TSL system for data transport a r 29 Figure 14 Effect of Network Jitter on Exciter s 10MHz Heierence ANEREN EEN 35 Figure 157 MD Radio Sample Ne Worms seksis dt a a aa aaa a a i a a i a i ous S a i i o a i 40 Figure 16 HD Radio Sample Network Small and Medium Large Network Deployment aaa aaa 41 Figure 17 Log showing Exporter receive buffer status ANERER 66 Doc No TX_TN_ 2040 Page 4 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements List of Tables Table 1 Payload combinations on a 950 MHZ STL SYStOM cccceecccecceeeeeeeceeeeeeeeaeeeeeeeeeaeeeeeseeeeeeseeeeeeseeeeeesaeeeeeessaeeeeessanseeesaees 27 Table 2 Payload Examples omn a TISTE er E TEE 30 Tables Payload Examples on an EMS TLC A AA ste po AAA 31 Table 4 Data Rates and Provi
15. all ports must be minimized In addition to broadcast and multicast packets this category also includes unicast packets sent to MAC addresses that are not in the switch s forwarding table This is a situation that occurs occasionally when a device from outside the local network Doc No TX_TN_ 2040 Page 24 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements sends packets to a device that was recently in the subnet The device is still in the router s Address Resolution Protocol ARP table but has already been aged out of the switch s forwarding tables which typically has an aging timer that is much shorter than the router s ARP aging timer There are steps that the network manager can take to prevent this situation One is to reduce the router s ARP aging timer to match the switch s forwarding table aging timer Another is to program the switch to block unicast traffic sent to unknown MAC addresses These steps involve a level of IT trickery that is best avoided these steps may not be available with all equipment and are not nearly as effective as creating a separate IP subnet for the WAN link Doc No TX_TN_ 2040 Page 25 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 STL TSL and WAN Links 5 1 STL Solutions for Data Transport and IBOC Applications Excerpted from Moseley Associates Inc New STL TSL Solutions for LAN WAN Extension to Transmitter Sites Bill Gould
16. anticipated The preferred method is to implement Virtual Private Network VPN tunneling using a device such as the Cisco PIX VPN Appliance at one or both ends of the system This configuration allows two Cisco Secure PIX Firewalls to run a simple virtual private network VPN tunnel from PIX to PIX over the Internet or any public network that uses IP security IPsec IPsec is a combination of open standards that provides data confidentiality data integrity and data origin authentication between IPsec peers For more information see Cisco Document 6211 Configuring a Simple PIX to PIX VPN Tunnel Using IPsec Another method though not recommended as it is far less secure is to configure the DSL router at the transmitter for IP forwarding to the Exporter Exciter IP address In this way all traffic addressed across the Internet to the DSL gateway will go directly to the Exporter Exciter See your DSL Router s user manual for information on IP forwarding not all routers support this feature Doc No TX_TN_ 2040 Page 37 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 6 Appendix 6 1 Tables and Data Table 4 Data Rates and Provisioning by Service Mode Data Rates and Provisioning This table may be used in the R ired for M n rvi calculation of sufficient SU elei n Glial eg e bandwidth for the HD Radio WAN STL for the services Service Mode configured The right hand column indicates t
17. as equals and are serviced on a first come first served basis However with emerging mission critical applications that requires more bandwidth or a certain Service Level Agreement SLA a new model is needed to deliver the expected performance QoS provides the end to end framework to differentiate traffic and to deliver and guarantee bandwidth to mission critical applications Classification and Marking Constitutes interesting traffic Classify HD Data Stream traffic with an IP precedence value of three 3 and all other traffic at a lower precedence value Shaping and Policing Policies that configure how much bandwidth will be allotted to each application based on its required bandwidth HD streams should be hard coded and based on the details shown in Table 4 in the Appendix Congestion Management Determines how to prioritize traffic in the event of congestion The method if employed and available will be highly dependent on the networking manufacturer For more information on QoS configurations see Reference 1 5 3 6 Path Reliability Excerpted from Moseley Associates Inc Hitless Space Diversity STL Enables IP Audio in Narrow STL Bands Howard Friedenberg April 2005 Reference 5 Fading is the foremost consideration in path reliability The goal is to choose a fade margin to provide sufficient reliability for the link For a traditional long haul telecom link a preferred goal for path availability is 99 999 refe
18. configuration Doc No TX_TN_2040 Page 13 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 3 12E and E2X Network Message Structure 3 1 Conditions In our analysis the Importer was setup with the MPS core bandwidth allocation set to its minimum value of 48 kb s to allow allocation of the maximum core bandwidth to the supplemental services All tables in this section demonstrate the maximum program data unit PDU sizes for the given mode For the purposes of this document only hybrid HD Radio modes are discussed The message sizes and bandwidths referenced are as measured across an actual network using the Ethereal protocol analyzer The packet sizes include all overhead such as TCP UDP IP and Ethernet headers This was done so as to give a true accounting of the on the wire traffic loads for various configurations Extraneous network traffic was isolated through a network switch from the rest of the network so that only pertinent I2E and E2X traffic was analyzed In reality some extraneous traffic is likely to occur when the HD Radio system exists as part of a larger local or wide area network Packet collisions latency and jitter must be minimized through implementation of Best Networking Practices found in Reference 1 3 2 Message Structure Overview HD Radio messages are structured into three distinct Program Data Units PDUs based on the rate at which they are delivered A B
19. end managed switch e No guarantee of packet delivery This configuration continues to be studied by iBiquity and equipment manufacturers Other options such as Multicast Directed Broadcast and Multiple IP Sockets for Unicast are under consideration for future development Doc No TX TN 2040 Page 12 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 2 3 Dual Importer to Exciter Split Configuration OBSOLETE As an interim measure to address the issue of dropouts caused by network losses prior to the release of Importer Version 1 2 and Exporter Exciter Version 2 3 it was recommended that Multicast installations be implemented using a dual Importer configuration to take advantage of the more robust TCP protocol In this configuration a TCP IP connection is established between two Version 1 1 2 Importers running separated functions The local Importer at the studio runs the SPS Processor Client functions The local Importer sends and receives TCP data packets to and from the remote Importer located at the transmitter The remote Importer running the Connection Manager Logistics Processor and SQL database functions sends the TCP packets to the collocated Exporter over a bi directional data link Figure 5 shows the Dual Importer to Exciter Split Configuration on bidirectional STL DATA FROM Studio Bi DIRECTIONAL Transmitter AUTOMATION SUBNET _ LINK AES MPS Audio STL Xcvr gi
20. for hybrid analog and digital operation The AES digital audio stream is still required for the main digital program as well as a bi directional broadband Ethernet IP connection for the supplemental programs and data between the Importer and Exciter Only the Advanced Applications Services AAS such as multicast programming or data services are transported by this link and does not affect the main program digital service A bi directional link is required to accommodate the command and response nature of the I2E configuration The I2E configuration may be implemented in cases where a bidirectional connection can be established between the Importer and the Doc No TX TN 2040 Page 7 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Exciter This configuration is the least expensive to implement and is ideal in situations where the Importer and Exciter can be collocated within the same isolated local area subnet over a dedicated WAN WAN Extension This can be accomplished either via RF or terrestrial circuits For more information see Section 5 STL TSL and WAN Links Prior to Importer Version 1 2 1 and Exciter Version 2 2 5 the only network protocol available for I2E was bi directional UDP IP With its lack of error correction the UDP protocol is susceptible to network faults The loss of even a single IP packet over the link will result in the loss of an entire frame which represents 1 48 seconds of Multicast or dat
21. in some cases six audio channels plus the Ethernet connectivity to support IBOC applications and LAN WAN networking applications plus RS 232 channels for remote control systems and RBDS LANLINK can be used with the Moseley Starlink SL9003Q digital STL system as well as all Moseley models and those of other manufacturers Doc No TX TN 2040 Page 28 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 1 3 T1 STL TSL System for Data Transport T1 systems are well suited for program audio voice and data networking T1 is a 1 544 megabit per second bidirectional data circuit These circuits are commonly found as leased T1 circuits from the local telephone company fiber links T1 microwave or digital soread spectrum radio links T1 spread spectrum radio links occupy the unlicensed ISM bands located at 2 4 GHz or 5 8 GHz A T1 STL TSL system should be considered if the answer is yes to any of the following questions No line of sight path to the transmitter 950 MHz frequencies overcrowded Need to backhaul audio from remote pick up RPU satellite downlink and air monitor Requirements include telephone voice channels for off premises extension or remote PBX interconnect e Desire to save money by consolidating multiple leased voice or data lines onto one digital circuit STL using T1 circuits overcomes the problem of no line of sight to the transmitter building whether it is caused by local obstruct
22. low cost IP based accessories are widely available at electronic discount stores Station IT and engineering personnel can look forward to marrying these innovations with core broadcast technology to provide unique new solutions One thing is certain the need for data access at the transmitter will surely grow Choosing the STL system which is correct for the data application and that has a migration path for future expansion is the best solution for LAN WAN extension to the transmitter site Doc No TX_TN_ 2040 Page 31 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 2 Protocols For the I2E protocol transport a bidirectional STL TSL WAN path is required to support its command and response nature as well as the default TCP IP protocol DE may be transported either UDP or TCP UDP is the default protocol for E2X and the only protocol that is currently supported A simplex transport is all that is required for E2X UDP Future releases of the Exporter Exciter may support TCP 5 3 Link Quality 5 3 1 Packet Losses In order for an HD Radio data network using a UDP data stream to function properly great care must be taken to avoid dropped IP packets in the STL TSL or WAN transport Any dropped IP packet will result in a loss of at least 1 5 seconds of HD Radio programming The average rate of the UDP HD Radio stream should not exceed 75 of the link s available bandwidth This is necessary to avoid any pote
23. packets across the network TCP relies on a bidirectional connection to acknowledge accurate receipt by the receiving host of the data packets sent by the transmitting host If a packet is lost or damaged it is resent The TCP implementation of both the I2E and E2X protocol is nearly identical to the UDP implementations except that there is a 64 byte acknowledgement message sent back to the sender for each request and response IP packet and the data packets themselves will contain an additional 20 bytes consisting of the TCP header information The use of TCP adds between 7 and 12 overhead to the data stream s average bandwidth depending on the configuration and service mode In I2E the Exporter sends a request for the needed data to the Importer the Importer responds with an acknowledgement of the request followed by the requested data packets The Exporter responds with an acknowledgement that the packets were or were not properly received If there was an error the missing packets are resent by the Importer and acknowledged by the Exporter In E2X there is no request the Importer simply sends at the PDU rate and the Exporter responds with an acknowledgement that each IP packet was received If there is a discrepancy the missing data will be resent The TCP protocol is not fully implemented or supported in Exporter Exciter Version 2 3 3 See the following tables in the Appendix Table 27 Service Mode MP1 E2X TCP Data Frame Structure
24. pair uncompressed One stereo pair uncompressed One stereo pair uncompressed 056 kb s One pair 2 channels 0 44 1 kb s Compressed 256 kb s NOTE Other combinations of program audio voice and data channels are possible up to the total bandwidth of the El circuit Digital 11 E1 spread spectrum radio systems are available in 1 2 or 4 T1 or E1 capacity Using a 2 or 4 11 E1 system is a perfect solution for a cluster of stations feeding combined transmitter sites The combined payload of program audio voice and data circuits to support multiple radio stations over a single high capacity link is a cost effective alternative to employing individual circuits for each station or service 5 1 5 Conclusion Implementing a data link to transmitter sites can provide stations with new functionality efficiency and safety as well as lower operating costs Choosing the STL is as much a matter of preference as the payload Choices range from a 950 MHz STL with data capabilities for one way data applications to a 950 MHz STL and a 900 MHz LAN extender to provide bidirectional networking solutions For more complex audio voice and data networks T1 STL and T1 E1 STL over 5 8 GHz RF links can concentrate more traffic over a given link and be more payload efficient and save on transport link costs when compared to the multiple discrete services it replaces Web browser equipment control is fast becoming standard equipment on broadcast products New
25. second Both I2E and E2X configurations require an Ethernet data channel to the transmitter to transport Program service Data PSD Advanced Application Services AAS and Supplemental Program Service SPS data In the E2X scenario the MPS digital audio is carried in the Ethernet stream as well Depending on the service mode services offered HD Radio protocol used and additional resources required by other applications careful consideration must be given to provisioning bandwidth When using TCP the WAN link must have a minimum of 40 overhead reserve bandwidth in order to function properly and UDP must have a minimum of 25 overhead This overhead should be calculated upon the total traffic expected through the link Traffic can consist of the following components IBOC data stream Traffic from management utilities such as VNC and telnet Any broadcast and or multicast traffic All auxiliary traffic used for other purposes such as Internet VoIP security and remote control Doc No TX_TN_ 2040 Page 32 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements The sum total of this traffic should occupy no more than 60 of the provisioned bandwidth for TCP and 75 for UDP If other traffic is going through the WAN link the link should have some class of service Quality of Service QoS or other priority queuing technique employed to ensure that the IBOC traffic has its required bandwidth under all conditions
26. transmitted data since the BER might be reduced lowering the number of packets that had to be resent Bit error rate does not directly correspond to packet losses The packet loss depends on the Doc No TX_TN_ 2040 Page 36 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements size of the packets being transmitted and the un recovered bit errors For example a BER un recovered of 10 with a packet size of 1000 bits will result in a 100 packet loss Bit error rate can be measured through a T1 circuit using a device such as a T1 Bit Error Rate Detector T BERD or Acterna Analyzer 5 4 Using the Public Network With the proliferation of inexpensive high speed Internet connections such as Digital Subscriber Line DSL some facilities have opted to use tunneling through the Internet as a viable HD WAN delivery transport method A DSL connection to the Internet is installed at the transmitter site for the Exporter Exciter and the studio site uses the station s router and gateway to access the Internet connection Reports are that this can work quite well if configured properly For both I2E and E2X protocols the uplink bandwidth of the circuit must meet the minimal provisioning for the protocol mode and configuration used Network reliability is also an issue to be considered Typically tunneling over DSL through the Internet will be far less robust than a dedicated point to point circuit Some loss and dropout can be
27. 4 kb s on P3 E gt P1 SIG REQ 94 E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ 94 94 94 94 94 94 94 94 I E P3 ACK I E P3 ACK I E P3 ACK I E P3 ACK I E P3 ACK I E P3 ACK I E P3 ACK I E P3 ACK 64 64 64 64 64 64 64 64 k ww gt __ Doc No TX TN 2040 Page 57 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 22 Service Mode MP3 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 MP3 I2E TCP Data Frame SPS1 at 32 kb s on P1 SPS2 at 24 kb s on P3 E gt l P1 REQ 94 E gt l P1 ACK E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK 64 64 64 64 64 64 64 64 Doc No TX_TN_2040 Page 58 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 23 Service Mode MP3 I2E TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 MP3 I2E TCP Data Frame SPS1 at 48 kb s on P1 SPS2 at 24 kb s on P3 E gt l P1 REQ 94 E gt I P1 ACK E gt P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt P3 REQ I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK 64 64 64 64 64 64 64
28. 64 en Doc No TX_TN_2040 Page 59 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 24 Service Mode MP1 E2X UDP Data Frame Structure P1 PIDS MP1 E2X UDP Data Frame P1 PIDS Se Doc No TX TN 2040 Page 60 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 25 Service Mode MP2 E2X UDP Data Frame Structure P1 P3 PIDS MP2 E2X UDP Data Frame P1 P3 PIDS 7 O I I Doc No TX TN 2040 Page 61 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 26 Service Mode MP3 E2X UDP Data Frame Structure P1 P3 PIDS MP3 E2X UDP Data Frame P1 P3 PIDS Se Doc No TX TN 2040 Page 62 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 27 Service Mode MP1 E2X TCP Data Frame Structure P1 PIDS MP1 E2X TCP Data Frame P1 PIDS P1 ACK 420 PIDS ACK PIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKIPIDS ACKJPIDS ACKIPIDS ACK PIDS ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Cik ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK Clk ACK 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 64 en TTT Doc No TX TN 2040 Page 63 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements
29. A lotes 31 Dee FrOlOCO oro crios 32 Doc No TX_TN_2040 Page 2 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 27 WOO ANY EE 32 Dd la Packet LOSSES EE 32 53 2 Balidwidili ie Een Une EE 32 5 3 2 1 BurSEBR3 Considera IN NEE 33 Doro MAON E 34 55 4 INCIWO NUM a aa a a a a N 34 53 9 E le Service ene E te EE 36 536 A a a A N N 36 5 97 E E e 36 545 Using he ie le Ee 37 6 APPENDIX ee 38 6 12 Fables le HE 38 6 2 I2E Exporter Receive Buffer Monitoring E 66 A EE een 67 REFERENCED DOCUMENT Sisi A aE 69 Doc No TX_TN_2040 Page 3 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements List of Figures Figures 1 MPS and MPSD over Simplex STL mcr sis ii ii saw ii i a i i i k kasqa 6 Figure 2 Studio Importer connection over bi directional duplex GIL 7 Figure 3 Importer to Exporter to Exciter Configuration a A A Di 9 Figure 4 Single Exporter to Multiple Exciters configuration aaa aaa saaa aaa aaa aaa Aaaa aaa saaa aaa aaa aaa aaa aaa 11 Figure 5 Local and Remote Importer Split Configuration on bidirectional STI 13 Figure 6 Recommended network deployment a asas saaa aaa aaa asas aaa aaa aaa aaa aaa saaa aaa aaa aaa aaa aaa aaa 19 FIGURE Z IMproper ne iWork de BIOVIMIE NES kais i sis nis i aa ai i i i a i a a i a a a a 19 Figure 8 The Seven Layer OSI Networking Model aaa aaa aaa
30. Cisco Catalyst Express 500 e Cisco Catalyst 2960 e 3Comm Office Connect series NOTES These are minimum criteria and just a few of the products that may be used Should other manageability and security features be required then a higher end switch may be needed to support additional features Doc No TX_TN_ 2040 Page 22 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 4 3 Switch Configuration Switch configuration can be a daunting task and must be considered as part of the larger network design Each manufacturer and model supports different features configurations and management Additional features and requirements inevitably increase the complexity of configuring the switches In house or corporate IT personnel should be consulted and will be of great help in configuring your HD Radio network Skilled network engineers may be required to configure switches and routers in a complex installation Those not having access to in house personnel may do well to consider contracting with a networking consultant We have attempted here to provide some general guidance for switch configuration For more detailed discussions see Reference 1 HD Radio Networking Best Practices and Reference 2 HD Radio Networking Implementation Recommendations Consult your particular switch s user manual for specific guidance 4 3 1 Configuring Virtual Local Area Networks VLANs A VLAN is a group of end sta
31. For more information on provisioning for various configurations see Table 4 Data Rates and Provisioning by Service Mode BEE Doc No TX TN 2040 Page 8 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 2 2 Exporter to Exciter E2X Figure 3 shows the Exporter to Exciter configuration Simplex or AES Audio to Legacy Legacy Studio Duplex Transmitter Analog Transmitter AES Audio STL AES Audio E2X Simplex UDP XMTR iais G3 Exciter Exgine Switch 14 Exporter AES Audio 2E Bi Directional UDP Figure 3 Importer to Exporter to Exciter Configuration The Importer to Exporter to Exciter E2X configuration is the most bandwidth efficient method of deploying an HD Radio Multicasting Data Network This platform consists of one additional product called the Exporter and employs the Exciter in the G3 or Exgine mode With this implementation a single data stream is conveyed to the transmitter site containing the main program digital audio along with the supplemental programs and all of the associated data The Exporter and Importer along with the audio processing are located at the studio site The Exporter performs two functions i handling the MPS digital audio and MPS data and accepting the AAS and SPS data streams coming from the Importer and ii combining all these services for transport over the STL to the transmitter site The main program digital audio is delivered
32. Hz STL System Examples of Payload Combinations on a 950 MHz Digital STL System at 32 QAM Ethernet Data Additional Audio Channels One stereo pair uncompressed et One stereo pair uncompressed E EE One pair 2 channels 44 1 kb s and 1 RS 232 pene BIS ane Compressed 256 kb s Two stereo pair uncompressed X X 32 kb s and 2 RS 232 NOTE Other combinations of program audio RS 232 and LAN data channels are possible up to the total channel bandwidth Because this is a one way path true networking possibilities are greatly limited 5 1 2 Creating a LAN WAN Extension to the Transmitter Site In addition to the outbound data connectivity available on a digital 950 MHz STL an inbound return portion of the link is needed to provide true networking functions and bidirectional control and telemetry services Until now this has required licensing additional transmitter to studio link TSL channels or leasing circuits from the local telephone company When it comes to adding data services broadcasters would prefer to avoid licensing delays and the frequency coordination expense associated with acquiring new TSL frequencies or the recurring monthly expense that comes from leasing additional circuits from the telephone company Due to the extensive installed base of 950 MHz systems an independent data transport link which works alongside a 950 MHz STL as shown in Figure 3 will solve broadcasters data transport requirements in a large num
33. Hz STL system with Ethernet The Moseley Starlink SL9003Q STL system is an example of a system which can be equipped for data transport in addition to AES digital program audio Starlink s Audio Source Encoder and Decoder modules have a built in RS 232 data channel This serial data rides for free because it consumes no extra transport bandwidth These RS 232 paths will support data for RBDS or the command side of a remote control system B _ u E D A a E m u l u A B B u E A An optional multiplexer and Ethernet module can be added to the Moseley Starlink system as well This can provide the one way Ethernet UDP data path to the transmitter site necessary for IBOC applications Doc No TX_ TN_2040 Page 26 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 1 1 1 Payload capabilities of a 950 MHz STL System The payload capabilities of a 950 MHz STL are a function of the allowable bandwidth of the channel it occupies and the Quadrature Amplitude Modulation QAM rate used available on the SL90030 are 16 32 64 128 256 QAM For example at 32 QAM a 950 MHz STL is capable of accommodating one 44 1 kb sstereo audio channel and an Ethernet channel operating at more than 600 kb s This combination provides more than ample throughput to support IBOC applications in either configuration as shown in Table 1 Table 1 Payload combinations on a 950 M
34. P3 ACK 64 64 64 64 64 64 64 64 q lt AA 2 gt Doc No TX_TN_2040 Page 54 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 19 Service Mode MP2 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 MP2 12E TCP Data Frame SPS1 at 32 kb s on P1 SPS2 at 12 kb s on P3 E gt l P1 REQ 94 E gt l ACK E gt l P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt P3 REQ I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK 64 64 64 64 64 64 64 64 Doc No TX_TN_2040 Page 55 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 20 Service Mode MP2 I2E TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 MP2 12E TCP Data Frame SPS1 at 48 kb s on P1 SPS2 at 12 kb s on P3 E gt l P1 REQ 94 E gt ACK E gt P3 REQ E gt l P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt l P3 REQ I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK I gt E P3 ACK 64 64 64 64 64 64 64 64 k ww gt ___ Doc No TX TN 2040 Page 56 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 21 Service Mode MP3 GE TCP Data Frame Structure SPS1 at 24 kb s on P3 MP3 I2E TCP Data Frame SPS1 at 2
35. Q E gt l P3 REQ E gt l P3 REQ E gt l P3 REQ E gt l P3 REQ E gt l P3 REQ 64 64 64 64 64 64 64 64 7 O OSS Doc No TX_TN_2040 Page 47 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 12 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 24 kb s on P3 MP3 I2E UDP Data Frame SPS1 at 24 kb s on P3 E gt l P1 REQ 64 E gt P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt l P3 REQ 64 64 64 64 64 64 64 64 SES Doc No TX TN 2040 Page 48 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 13 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 MP3 I2E UDP Data Frame SPS1 at 32 kb s on P1 SPS2 at 24 kb s on P3 E gt l P1 REQ 64 E gt P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt P3 REQ 64 64 64 64 64 64 64 64 masr S I Doc No TX TN 2040 Page 49 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 14 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 MP3 I2E UDP Data Frame SPS1 at 48 kb s on P1 SPS2 at 24 kb s on P3 E gt l P1 REQ 64 E gt P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt l P3 REQ E gt P3 REQ 64 64 64 64 64 64 64 64 E A A 2 gt _ zz
36. Routing tables can be manually configured or discovered using routing protocols but unlike switches routers will always require some configuration Each interface on the router is on a different network or VLAN On any given interface broadcasts will be localized to that interface only and its connecting switch These broadcasts will not leak over to other interfaces To minimize broadcast traffic over the STL the HD Radio network should be configured on a separate subnet from the office program automation using a Layer 3 router or switch The term router and Layer 3 Switch are often used interchangeably A router actually supports differing media interfaces such as Ethernet FastEthernet Gigabit Ethernet ATM T1 T3 SONET DSL and ADSL a switch usually supports only one media interface type Though they vary in interface support the routing functionality is the same Large switches may also include a router This is often described as Layer 3 switching but it is functionally identical to routing Doc No TX_TN_2040 Page 20 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements In a typical scenario a router would be used to terminate the WAN connection that is the T1 connection The core switch would perform the Layer 3 routing for the internal network VLAN and have a default route pointing to the WAN router Port trunks would be established between the Layer 3 Router and the Layer 2 switches to compris
37. Up Op Sy Legacy Transmitter STL Xow BAS i TCF amp UDP a a HD Exciter a AES Audic AES Audio to Analoc TCP TCE y Switct AES SPS Audic LAR A May be on eiter Automation or Transmission SubNet Must be on isolated Transmission Subnel Figure 5 Local and Remote Importer Split Configuration on bidirectional STL Up to nine frames 13 32 seconds of AAS data may be buffered between the two units When one or more packets are lost in transmission the TCP requests retransmission of missing packets If packet losses across the network exceed the contents of the buffer or its ability to recover significant dropout minimum of 15 seconds will occur and loss of the Logistics Processor connection is possible requiring a restart of both Importers The use of buffering between the Clients and Logistics Processor allows for a fairly robust connection across a typical WAN or STL with at least 128 kb s bandwidth and less than 50 millisecond latency and packet loss of less than 10 in MP1 Mode Obviously this is not an ideal implementation Beginning with Importer Version 2 0 and Exporter Exciter Version 2 2 5 the local Importer and the Exciter can communicate directly using TCP IP and the split configuration will no longer work or be supported The configuration is show here only to support those installations where it is still in use Future releases of this document will drop this
38. X Site 3 SMS CSU DSU w ET Exciter il Exporter Set to Exciter IP 192 168 10 255 Broadcast HD Radio VLAN Subnet 192 168 10 xxx Figure 4 Single Exporter to Multiple Exciters configuration IP broadcast addresses are used for single packet one to everyone delivery A sending host addresses the IP packet using a broadcast address and every node on the sending node s network segment receives and processes the packet IP broadcast addresses can be used only as the destination IP address Network broadcasts are used to send packets to all hosts of a classful network which listen for and process packets addressed to the network broadcast address IP routers do not forward network broadcast packets Network broadcasts use the UDP protocol A broadcast sent to a subnet in the form 192 168 10 255 is a subnet broadcast if the subnet mask is 255 255 255 0 All hosts on the network with an IP address of 192 168 10 1 through 192 168 10 254 would receive the broadcast The advantages of this methodology are e Uses only a single UDP data stream of bandwidth e Operates over a simplex one way network e Requires no changes to the Exporter Exciter platforms Doc No TX TN 2040 Page 11 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements The disadvantages of this methodology are e Difficult to manage the high volume of broadcast traffic in a large network e Requires the use of a high
39. _TN_ 2040 Page 5 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 1 Overview The purpose of this document is to aid the station engineer in the successful integration and connection of various networked components necessary for the implementation of HD Radio Advanced Application Services specifically Multicasting Further this document will provide a frame of reference and understanding to manufacturers developers and consultants in refining and fulfilling present and future needs for this critical element of the HD Radio system This application note represents the current understanding of the state of the art in data networking as it applies to the HD Radio system Ongoing research by iBiquity Digital in cooperation with our broadcast equipment manufacturing and radio station partners as well as contracted consultants will contribute to updates and future releases of this document Minimizing network induced dropouts is a prime consideration for the successful implementation of an HD Radio system A successful implementation is defined here as 99 9 uninterrupted transmission of the radio station s digital components This is in line with accepted communications industry standards and typical of most Studio Transmitter Link STL and leased T1 circuits See References 5 and 6 In its simplest form the Main Program Service audio MPS is the station s main HD Radio program and the Main Program Service D
40. a Frame Rate PDU P2 and P3 messages are Block Pair Rate PDUs P2 is applicable only to the all digital modes The I2E interface can be configured to implement either bi directional UPD IP or TCP IP packets TCP is the default and preferred method Both approaches are very similar in structure We will first discuss the UDP implementation for the sake of simplicity 3 3 1 MP1 I2E UDP Data Frame Structure For MP1 the maximum core bandwidth available to the supplemental services is 48 kb s This may be divided between the supplemental program and data services In Block Zero 0 the Exporter sends a 64 byte request for data to the Importer The Importer responds with a single P1 message With a 48 kb s SPS channel the P1 message will be an 8 022 byte packet transmitted in the first 7 5 milliseconds of the frame This is repeated at the frame rate every 1 48 seconds The connection remains silent until the next request is sent For detailed information on the structure and timing of the MP1 I2E UDP data frames see the following tables in the Appendix Table 6 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 12 kb s on P1 Table 7 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 32 kb s on P1 Table 8 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 48 kb s on P1 3 3 2 MP2 I2E UDP Data Frame Structure MP2 makes an additional 12 kb s of bandwidth available for supplemental services through logical chan
41. a service programming With the release of Importer Version 1 2 1 and Exciter Version 2 2 5 TCP is the default protocol and UDP should not be used Using TCP IP also provides up to 20 frames of receive buffering between the Importer and Exporter to allow sufficient time for retransmission of dropped TCP packets Given the additional robustness afforded for little additional network overhead and considering that a bi directional link is required for this service anyway there is little reason to use UDP In this configuration even with moderately bad network conditions up to 1 packet loss and 100 millisecond latency the system continues to perform well The key is to provide an adequate bandwidth overhead to allow the system to recover from lost packets If a WAN link is provisioned such that the data stream occupies no more than 60 of the WAN link s bandwidth then the installation should be successful even under all but the most adverse network conditions I2E average bandwidth ranges between 17 kb s and 156 kb s depending on the configuration and IP protocol used A WAN STL bandwidth of at least 90 kb s with latency of less than 100ms is necessary for MP1 mode running a single 32 kb s SPS over TCP A 128 kb s LAN WAN Extender or two 2 DSOs will provide sufficient bandwidth for any MP1 configuration For the maximum MP3 configuration 1 SPS at 48 kb and 1 SPS at 24 kb the minimum STL bandwidth is 156 kb s requiring three 3 DSOs for 196 kb s
42. affic on a particular port or ports for analysis To do this one port of the switch is designated as a monitor port and then assigned the port or ports to be monitored The packet analyzer is connected to the monitor port and all or selected traffic to or from the port being monitored is available for analysis Consult your particular switch s user manual for specific guidance on using the SPAN features 4 3 3 Spanning Tree Protocol Spanning Tree Protocol is a link management protocol that provides path redundancy while preventing undesirable loops in the network For an Ethernet network to function properly only one active path can exist between two stations The spanning tree network protocol provides a loop free topology for any LAN Doc No TX_TN_ 2040 Page 23 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements or bridged network The Spanning Tree Protocol which is also referred to as STP is defined in the Institute of Electrical and Electronics Engineers IEEE Standard 802 1D When you run STP all ports that are included in the spanning tree process become active much slower than they otherwise would become active Despite the time that the process involves STP is beneficial but can cause delays of up to 1 minute in the connection re connection of the I2E or E2X streams which is certainly unnecessary and may be undesirable Cisco uses the PortFast or fast start feature on most of its switches When t
43. ata MPSD is the artist song title and other program information that is displayed on the listener s radio are conveyed from the studio program automation system to the HD Radio RF Exciter remotely located at the station s transmitter facility Providing MPS MPSD alone requires only a stereo 44 1 kHz or 32 kHz sampled AES digital audio channel along with a low bit rate simplex User Datagram Protocol UDP Ethernet connection less than 400 bits per second for the MPSD This can be accomplished using most modern digital STL systems as explained in Section 5 1 Figure 1 shows MPS and MPSD transmission over simplex STL AES Audio to Legacy Analog Transmitter Studio Transmitter AES Audic AES Audic PAD Data 40Cbp s HD Simplex UDP Exciter Figure 1 MPS and MPSD over simplex STL Doc No TX TN 2040 Page 6 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 2 HD Radio and AAS System Configurations Advanced Application Services AAS allows the HD Radio system to multiplex additional channels of program and data services into an existing HD Radio transmission through the use of an appliance called an Importer By far the most compelling and widely deployed application for these services is the Supplemental Program Services or Multicasting Currently with Multicasting it is possible to transmit two additional digital audio programs as well as multiple streams of data Future implementations wil
44. ata These 13 frames will be sent at very near the wire speed 10 megabits per second Each Ethernet frame takes approximately 1 2 milliseconds While there are gaps between the packets these are typically very short less than 200 us For 13 packets of 1500 bytes each being sent at intervals of approximately 1 25 milliseconds the 20 000 byte burst takes approximately 16 25 milliseconds to transmit on a 10 megabit per second Ethernet During this burst the data rate is approximately 9 7 megabits per second Some concern has been raised that this burst data rate might overwhelm the WAN link which would only require a bandwidth of 192 kb s for the configuration being considered in this example The concern however is a false one When faster links are connected via slower links it is normal for the data to arrive at the bridging device in bursts much higher than the bandwidth of the slow connecting link A buffer is used to accommodate the incoming data until it can be sent over the slower link According to the rules of Ethernet bridging IEEE 802 1 the buffer of a bridge or switch can hold the packet for no more than 2 seconds before transmitting it After 2 seconds the packet must be discarded This rule requires the designers of bridging devices to provide a buffer that can hold at least 2 seconds worth of data at the lower link s speed For a 192 kb sbridged link this would correspond to approximately 40 kilobytes of data In the IBOC applicat
45. ayer 3 switch Stu dio Router Medium Large Network Deployment importer can reside op any WLAN Studio Layer 3 switchi Router Small Network Deployment iBiguity Digital Corporation 1 Core Switch performing La routing between Corporate Prophet and HD Radio VLAN The VLANs are extended from ihe La switch to the L switch via trunk ports 1 Managed Core Switch parforming La routing between Corporate VLAN and HD Radio VLAN This configuration is used in a small network where additional L2 switches are not needed and all computers ara connected to the same switch Transmitter Transmitter HD Radio Data Network Requirements Exciter HO Rado VEAN Importer can reside on any VLAN Filename Sample Network vsd HD Radio TM MT Sample Network SE Figure 16 HD Radio Sample Network Small and Medium Large Network Deployment Doc No TX TN 2040 Page 41 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 6 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 12 kb s on P1 MP1 I2E UDP Data Frame SPS1 at 12 kb s on P1 E gt P1 REQ 64 Doc No TX_TN_2040 Page 42 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 7 Service Mode MP1 GE UDP Data Frame Structure SPS1 at 32 kb s on P1 MP1 I2E UDP Data Frame SPS1 at 32 kb s on P1 E gt I P1 REQ 64 Doc No TX_TN_2040 Page 43 Rev 09 iB
46. ber of cases These stations can continue to use already installed 950 MHz equipment infrastructure and leverage the STL channels they already have licensed Moseley s high speed Ethernet IP RS 232 data transport system the LANLINK HS 900D LAN Extender Data Link provides this functionality LANLINK transports bidirectional Ethernet and RS 232 serial data over a license free 900 MHz FF link Because of the closeness in frequency to the 950 MHz STL band LANLINK can be combined into an existing 950 MHz antenna system which eliminates the need to purchase and install an additional antenna system or add additional tower lease costs and tower wind loading If desired however a station can to create a stand alone data link by installing an antenna system for LANLINK Figure 12 shows a 950 MHz STL system with a 900 MHz LAN Extender Data link Doc No TX TN 2040 Page 27 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Studio x Transmitter Site j p mitters HDC PSD SAC AAS AES x RBDS Audio Ethernet RS 232 Dir Ethernet 950 MHz STL transports AES digital audio 900 MHz LAN Extender transports bidirectional Ethernet and RS 232 data and supports IBOC applications Figure 12 950 MHz STL with 900 MHz LAN Extender Data Link LANLINK operates in the 902 928 MHz Industrial Scientific and Medical ISM band so no license is required It uses robust digital frequency hoppin
47. ch may be used for supplemental services In MP2 mode the clock and PIDS messages continue to be sent at the block rate and P1 continues to be sent at the frame rate The 288 byte P3 message is added at the block pair rate For MP2 the E2X frame size is 24 536 bytes and requires a bandwidth of 132 kb s For detailed information on the structure and timing of the MP2 E2X data frames see the following table in the Appendix Table 25 Service Mode MP2 E2X UDP Data Frame Structure P1 P3 3 4 3 MP3 E2X UDP Data Frame Structure For MP3 mode logical channels P1 and P3 and PIDS are again used P3 has been expanded to add an additional 12 kb s of bandwidth for a bandwidth of 24 kb s to be used for supplemental services The structure of the frame remains the same as in MP2 except that the P3 block pair rate PDUs are now 688 bytes and the frame size is 27 736 bytes requiring 149 kb s of network bandwidth For detailed information on the structure and timing of the MP3 E2X data frames see the following table in the Appendix Table 26 Service Mode MP3 E2X UDP Data Frame Structure P1 P3 Doc No TX TN 2040 Page 17 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 3 4 4 TCP Implementation of DE and E2X TCP provides a reliable data transfer between hosts in packet switched communications networks It uses the Internet Protocol IP as the underlying protocol and provides guaranteed delivery of
48. cies between the Exporter and Exgine will result in 1 dropped frame every 17 days 10 x 1 48 seconds frame 86400 seconds day 17 1days The use of GPS as a timing reference on both the Exporter and Exgine to precisely lock their respective clocks together eliminates both the phase and frequency issues and is highly recommended Beginning with Exciter v2 4 a PLL circuit in the DUCII firmware rev 2 14 or later allows the Exgine s 10MHz reference to be locked to incoming clock messages from the Exporter via the network This ensures absolute frequency lock preventing buffer underflow overflow and affords a 50 fold decrease in the timing jitter and may eliminate the need for GPS reference at the Exgine However recent testing shows that the timing jitter is larger than originally expected and the 50 fold decrease in processed jitter may not be sufficient for blend accuracy requirements For a complete discussion on the effects of jitter on the HD Radio system refer to Synch10Mhz Remote Clock Synchronizer Reference Design Application Note 7 Doc No TX TN 2040 Page 35 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 3 5 Quality of Service Configuration Quality of Service QoS is used to provide differentiated levels of service for selected traffic QoS applies to WAN configurations as well as some routers and switches In traditional data networking all traffic and applications are treated
49. e HD Radio iBiquity Digital Corporation Application Note HD Radio Data Network Requirements Rev 09 October 23 2006 iBiquity Digital Corporation Tim Anderson Alan Black Jeff Detweiler Muthu Gopal Russ lannuzzelli Steve Johnson Brian Kroeger MTM Technologies Inc Kurt VanderSluis Trieu Vu iBiguity Digital Corporation Copyright iBiquity Digital Corporation 8865 Stanford Boulevard All rights reserved Suite 202 The contents of this publication may not be reproduced in any media without the Columbia Maryland express written permission of iBiquity Digital Corporation 21045 USA Trademarks The iBiquity Digital logo iBiquity Digital iBiquity the HD Radio logo and the HD logo are registered trademarks of iBiquity Digital Corporation a HD Radio is a trademark of iBiquity Digital Corporation info ibiquity com All other trademarks whether claimed or registered are the exclusive property of their respective owners 410 872 1530 Telephone 410 872 1531 Facsimile TX_TN_2040 iBiguity Digital Corporation HD Radio Data Network Requirements Table of Contents Te MOVER VIEW EE 6 2 HD RADIO AND AAS SYSTEM CONFIGURATION S 7 2A IMPOrnerto eX CVO E EE 7 2 2 TEXPONer TO EXCO E EE 9 2 2 1 One Exporter to Multiple Exciters Configuration
50. e the VLANs Figure 9 shows a typical studio switch and router deployment Layer 3 VLAN are created on the master Switch Router switch to minimize broadcast traffic across the STL A L3 device is used at the core to route traffic between VLANs Corporate WAN In a large network a managed L2 switch is used to extend the VLAN y from the core switch out to the IDF via port trunks In a small network all connections could be made at the L3 switch Program Automation VLAN HD Radio VLAN Y May reside on either subnet Corporate VLAN STL Importer Exporter Figure 9 Typical studio switch and router deployment Switches should be deployed at both the studio and transmitter site to provide dedicated bandwidth and to remove collisions from the equation On the studio side an enterprise switch from Cisco HP or Nortel for example should be deployed to give greater functionality manageability security and visibility into the network Figure 10 shows a transmitter site deployment Low cost switch or even hub ie Dlink Netgear Linksys will usually suffice since BW requirements are minimal and VLAN and other management is not needed SET lt ES Exciter Figure 10 Transmitter site deployment At the transmitter site a low cost home office type switch from such brands as D Link Linksys or Netgear is more than adequa
51. er Exciter Exporter Generation 3 Exciter Exciter only Global Positioning System Graphical User Interface Importer to Exporter Protocol Metadata container for information such as title artist and album In Band On Channel Intermediate Frequency Internet Protocol Internet Protocol Security Industrial Scientific and Medical kb s Local Area Network megabits per second service Mode 1 96 kb s core service Mode 2 96 kb s core 12 kb s enhanced service Mode 3 96 kb s core 24 kb s enhanced Main Program Service Main Program Service Data Milliseconds Program Data Unit Program Information Data Service Phase Locked Loop Parts per million Program Service Data Radio Broadcast Data System Radio Data System Radio Frequency Remote Pick Up Station Information Guide Supplemental Program Service Studio Transmitter Link Network transmission of a DS1 formatted digital signal at a rate of 1 544 Mb s Transmission Control Protocol Transmitter Studio Link User Datagram Protocol Microseconds Doc No TX_TN_ 2040 Page 67 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements VLAN Virtual Local Area Network VoIP Voice over Internet Protocol WAN Wide Area Network Doc No TX TN 2040 Page 68 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Referenced Documents 1 MTM Technologies HD Radio Networking Best Practices Author Trieu Vu Date
52. etwork Requirements Transmitter HD Radio VLAN should only contain STL links This is crucial in reducing broadcast IDF traffic and misc traffic onte the WAN HD Radio VLAN Importer can reside in any VLAN Future software release might require the Importer to reside on the same network as the Prophet Servers Assess link quality by reviewing the following statistics RF Power Signal to Noise ratio RSSI Data Rate Packets Received Retries Retry errors Adjustment on RF Power or Antenna placement might be required to provide better throughput and lower error rate Please refer to the Design Guide for bandwidth sizing recommendations In summary more bandwidth will allow more room for error recovery retranmissions Review statistics on both sides of the link T1 or RF to assess the health of the link in each direction Low cost switch or even hub e Dlink Netgear Linksys will usually suffice since BW requirements are minimal and VLAN and other management is not needed Exciter Prophet VLAN consist only of Prophet servers and its associated components Mangement of Exciter from the Studio via VNC will require bandwidth overhead 50K Use Telnet 5K when feasible HD Radio TM Sample Network Filename Sample Network vsd Revision 7 2 Author Trieu Vu Revision Date 5 22 06 TECHNOLOGIES Figure 15 HD Radio Y Sample Network Doc No TX_TN_2040 Page 40 Rev 09 L
53. g and spread spectrum technology producing signals that can still be recoverable even with a very low signal to noise ratio The power output ranges from 100 milliwatts to 1 watt 20 dBm to 30 dBm This is sufficient to provide paths of up to 30 miles As a general rule where there is a working 950 MHz STL already in service LANLINK will operate comfortably In these situations it should not be necessary to conduct additional path studies LANLINK connects in line between the STL transmitter or receiver and the 950 MHz antenna system A built in duplexer in LANLINK combines the RF output of the STL and that of the LANLINK with less than 1 2 dB of insertion loss This eliminates the expense and additional tower loading of adding another antenna system The Ethernet data transport capabilities of LANLINK are 512 kb s 10BASE T for IP Ethernet connections With LANLINK the station LAN can be extended to the transmitter site with enough bandwidth capabilities to support services such as remote servers and IP equipment control as well as the IBOC data stream including its MPS SPS SPSD and AAS information Two RS 232 channels provide bidirectional serial data paths that can be set from 1200 bits per second to 115 200 bits per second for remote control or RBDS Using LANLINK as the data path allows the STL system to be devoted to audio transport The combination of LANLINK with Moseley s Starlink SL9003Q digital STL system can provide two four and
54. he minimum WAN bandwidth reguired for the particular service configuration O i This table does not account for i broadcast multicast extraneous traffic or other services that may be present on the network Avg Bandwidth Kb s Provision Kb s Protocol IP Protocol NIO N For other configurations and additional traffic use the following formula to calculate WAN bandwidth provisioning requirements WAN Provisioned Bandwidth X HD Other X 5 3 1 67 for TCP X 4 3 1 33 for UDP HD HD Stream In Other All other WAN traffic Doc No TX_TN_2040 Page 38 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 5 predicts the number of HD Radio data network dropouts that can be expected for a given network packet loss based on the number of packets sent per day when running UDP without error mitigation Table 5 Prediction of HD Radio data network dropouts due to network packet losses UDP Expected Daily HD Dropout Doc No TX TN 2040 Page 39 Rev 09 Studio VLAN are created on the master switch to minimize broadcast h traffic across the STL Gy Layer 3 switchi A L3 device is used at the core Router to route traffic between VLANs Corporate VLAN consist of users workstations file servers and printers iBiquity Digital Corporation In a large network a managed L switch is used to extend the VLAN from the core switch out to the HD Radio Data N
55. his feature is enabled the switch assumes that the port is not part of a loop and immediately begins forwarding packets Another way to do it is to turn off spanning tree for the switch but this is dangerous and should not be done in most environments More recently Rapid STP RSTP the IEEE Standard 802 1W has been implemented by manufacturers which reduces the connection time to less than 5 seconds CAUTION Never use the PortFast feature or turn off STP on switch ports that connect to other switches hubs or routers These connections can cause physical loops and spanning tree must go through the full initialization procedure in these situations A spanning tree loop can bring your network down 4 3 4 Trunking Protocols Another switch feature is the ability for a port to form a trunk A trunk is configured between two devices when they need to carry traffic from multiple VLANs A VLAN is what switches create in order to make a group of workstations appear to be on its own segment or broadcast domain Trunk ports make these VLANs extend across multiple switches so that a single VLAN can cover an entire campus In order to extend the VLANs in this way the trunk ports add tags to the packets that indicate the VLAN to which the packet belongs There are different types of trunking protocols If a port can become a trunk there is a possibility that the port can trunk automatically And in some cases the port can even negotiate the type of tru
56. ice Mode MP2 GE TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 Table 21 Service Mode MP3 GE TCP Data Frame Structure SPS1 at 24 kb s on P3 Table 22 Service Mode MP3 GE TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 Table 23 Service Mode MP3 GE TCP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 Doc No TX_TN_ 2040 Page 16 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 3 4 Exporter to Exgine Exciter E2X There is no request response exchange in the E2X protocol PDUs are merely sent from the Exporter to the Exciter at their predetermined PDU rate The P1 logical channel message is a Frame Rate PDU P2 and P3 messages are Block Pair Rate PDUs while the PIDS Program Information Data Service and the clock messages are Block Rate PDUs P2 and P4 are applicable only to the all digital modes MP5 MP6 and MP11 and are not discussed here Within each E2X data frame are the messages bound for the active logical channels Messages for the logical channels P1 MPS and SIG if present PIDS and the clock will always be present P2 and or P3 messages will also be sent as part of the frame if the Exporter is configured to use those channels MPS and SIG services are encoded into the P1 logical channel The supplemental services may be encoded within P1 or P3 depending on the service mode and configuration of the
57. ifacts due to instantaneous phase differences between the Exporter and Exgine reference clocks Ideally the transfer of PDUs in the Exgine should be locked to within 1 one 44 1KHz sample at he Exporter s audio card or about 22 7 usec for optimum blend performance Doc No TX_TN_ 2040 Page 34 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Jitter figures between 25 usec and 15 msec can cause comb filtering of the high frequencies during blends while higher jitter can result in a noticeable echo effect during blend Figure 14 shows 5 10 msec of network jitter with some outlying transients out to 20 msec Jitter was measured by observing the Exgine s E2X frame rate PDU boundary indication which is determined by counting the 16 E2X block rate clock message PDUs 2 00V B 2 00V 5002 Trigd 1 69V Figure 14 Network Jitter 50 msec div 1 hour of operation It should be noted that without GPS or some other method of providing absolute frequency lock between the Exporter audio card s 44 1KHz sample rate and Exgine s 10MHz reference receive buffer underflow in the Exgine or data overflow of the Exporter s audio cards will eventually occur resulting in data frame misalignment eventual audio dropout and significant diversity delay slippage The frequency of these dropouts is directly proportional to the frequency disparity of the two references For example a difference of 1 ppm in the clock frequen
58. iguity Digital Corporation HD Radio Data Network Requirements Table 8 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 48 kb s on P1 MP1 I2E UDP Data Frame SPS1 at 48 kb s on P1 E gt l P1 REQ 64 Doc No TX TN 2040 Page 44 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 9 Service Mode MP2 GE UDP Data Frame Structure SPS1 at 12 kb s on P3 MP2 I2E UDP Data Frame SPS1 at 12 kb s on P3 E gt P1 SIG REQ 64 E gt P3 REQ E gt l P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ 64 64 64 64 64 64 64 64 gt __ Doc No TX TN 2040 Page 45 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 10 Service Mode MP2 I2E UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 MP2 I2E UDP Data Frame SPS1 at 32 kb s on P1 SPS2 at 12 kb s on P3 E gt l P1 REQ 64 E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt P3 REQ E gt I P3 REQ E gt I P3 REQ E gt P3 REQ E gt P3 REQ 64 64 64 64 64 64 64 64 en Doc No TX_TN_2040 Page 46 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Table 11 Service Mode MP2 GE UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 MP2 I2E UDP Data Frame SPS1 at 48 kb s on P1 SPS2 at 12 kb s on P3 E gt l P1 REQ 64 E gt P3 REQ E gt l P3 REQ E gt P3 RE
59. ik ala dk GR Figure 13 Block diagram of a T1 STL TSL system for data transport Doc No TX TN 2040 Page 29 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 5 1 3 1 Payload Capabilities of a T1 System Payload capabilities of a T1 system are limited by the 1 544 megabits per second bandwidth of the T1 circuit Of this available bandwidth the bandwidth required to operate the audio channel at 44 1 kb s is 1 408 megabits per second That allows approximately 80 kb s for the LAN connection This is sufficient to carry the PSD component of HD Radio signal and to support some slow speed network capabilities To take full advantage of the capabilities of the T1 circuit engineers choose to operate the audio modules at 32 kb ssampling rates This consumes 1 024 megabits per second of the available T1 bandwidth leaving the remaining 512 kb s available for the LAN applications and other audio services Table 2 lists some payload examples on a T1 STL circuit Table 2 Payload Examples on a T1 STL Circuit Payload Examples on a T1 STL Circuit Ethernet Data Additional Audio Channels One stereo pair uncompressed One stereo pair uncompressed One stereo pair uncompressed 256 kb s One pair 2 channels 32 kb s and 1 RS 232 Compressed 256 kb s NOTE Other combinations of program audio voice and data channels are possible up to the total bandwidth of the T1 circuit The Moseley Starlink 9003T1 can be set up f
60. ion example that we are considering a configuration with the largest possible burst the burst of data Is approximately half of this maximum figure 20 kilobytes While it is possible to overwhelm a slower link with a burst of data transmitted from the faster link under normal data transmission with infrastructures constructed according to the recommendations outlined in this document this condition should never occur In the case of a packet loss rate higher than the 1 allowed however it could happen if the data stream got far enough behind and the system was sending Doc No TX_TN_ 2040 Page 33 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements at high data rates over more extended periods of time Under those conditions the bridge might be forced to discard packets because of the 2 second rule As a general note in almost all cases including this one the shortest period of time that needs to be considered in digital networking is 1 second Since the audio frame is approximately 1 5 seconds and almost all of it is sent during the first second the burst rate of an IBOC data stream is approximately 1 5 times the average data rate 5 3 3 Latency Latency is the amount of time it takes a packet of data to move across a network connection When a packet is being sent there is latent time when the computer that sent the packet waits for confirmation that the packet has been received Latency and bandwid
61. ions or longer distance requirements Radio station clusters are often made up of individual stations whose transmitter sites are located far outside the city where the studios are located T1 is a digital transport medium which delivers the same quality whether the circuit is across town or thousands of miles cross country with no increase in noise or loss of audio performance The true benefits of a T1 system are found in its payload capabilities In addition to digital program audio delivery to the transmitter you have the following benefits e Full T1 bandwidth inbound TSL for program quality audio backhaul of satellite downlink channels e Remote pickup RPU receivers collocated at transmitter sites e Off air confidence monitoring for EAS receive audio Additional bidirectional audio services include 4 wire and 2 wire voice circuits for FSK transmitter control FXO FXS telephone and fax or intercom extension across the link Data channels provide additional Ethernet and RS 232 data connections Figure 13 shows a block diagram of a T1 STL TSL system for data transport Studio A TSL Transmitter site E ode i ale le and IBOC Trans mitters AES Audio Ethernet RS 2 32 Phone Y Nooo sika e le uka shka H oo A e sie E e e ecos e oo e Bs BL Y ie e sha dia H a le le R T1 E1 STL transports bidirectional AES digital audio telephone voice Ethernet and RS 232 data and supports IBOC applications WS E s
62. istances or can use smaller antenna systems than fixed frequency radio systems in the same bands Often paths of 30 to 40 miles can be achieved This line of site STL solution operates license free in the 2 4 GHz or 5 8 GHz ISM bands T1 over spread spectrum radio avoids the recurring monthly costs of leasing T1 lines from the telephone company Doc No TX_TN_ 2040 Page 30 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Because the ISM bands are unlicensed there are no expensive frequency coordination studies and license application fees Systems can be deployed and changes made quickly Stations operating exclusively on microwave spread spectrum links can take advantage of an added bonus Since they have no ties to the T1 network these stations have the option of operating their systems at El rates El is the international standard which operates at 2 048 megabits per second instead of the domestic standard of 1 544 megabits per second in a T1 circuit This results in an additional 28 of payload capacity in E1 systems Table 3 shows some combinations of audio and data which are possible in an E1 system Careful selection of the bandwidth assignments makes it possible to transport additional audio voice and data services in an E1 system and support IBOC applications Table 3 Payload Examples on an E1 STL Circuit Payload Examples on an E1 STL Circuit Ethernet Data Additional Audio Channels One stereo
63. l include advanced services such as Conditional Access Electronic Program Guides Weather and Traffic information as well as additional supplemental program services The Importer is usually located at the studio It concentrates the audio and data information from the various program sources and services into a single data stream to be conveyed to the Exporter Exciter as Internet Protocol IP data over an Ethernet connection There are three distinct physical configurations that the station may implement for deployment of AAS for Multicasting on the HD Radio system 1 Importer to Exciter I2E 2 Exporter to Exciter E2X 3 Dual Importer to Exciter Split Configuration 2 1 Importer to Exciter I2E Figure 2 shows the Studio Importer connection over bi directional duplex STL aan nnn ees I O 1 Studio Transmitter DATA FROM AES Audio to Legacy Transmitter AUTOMATION S DUPLEX LINK AES MPS Audio AES Audic Crossover Cable Hub Lz or L3 Switch may be inserted depending on external connectivity requirec May be on either Automation or Transmission Subnet Must be on isolated Transmission Subnet Figure 2 Studio Importer connection over bi directional duplex STL The I2E configuration connects an Importer to an Exporter Exciter via either bi directional UDP or Transmission Control Protocol TCP over an Ethernet connection With this implementation two data streams are conveyed to the transmitter site
64. l is considered Enhanced and can convey an additional 12 24 kb s P3 can be configured to carry one or more supplemental programs or data services P3 is sent at the Block Pair rate e PIDS logical channel contains information required for fast acquisition of the station information PIDS is sent at the Block rate and only in the E2X protocol e Clock is used for E2X frame synchronization and is sent at the Block rate and only in the E2X protocol Doc No TX TN 2040 Page 14 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements While there are slight differences in the data structure and content the basic form of the streaming data frames remains the same for all HD Radio networked streaming protocols See the Appendix for the structure and content of specific modes and configurations 3 3 Importer to Exporter I2E Requesis for data are sent from the Exporter to the Importer The Exporter responds with a single logical channel data message Each logical channel is requested and sent discreetly Each configured supplemental service is encoded within one of the active logical channels Bandwidth requirements of the I2E interface are highly dependant on the Importer s supplemental services configurations MPS data is not sent from the Importer In configuration modes where only the MPS is on P1 SIG data will still be present There are also no PIDS or Clock data messages in I2E The P1 logical channel message is
65. lock Rate PDU is delivered every 92 5 milliseconds while a Block Pair PDU is delivered at an interval of 185 milliseconds and a Frame Rate PDU is delivered every 1 48 seconds A Frame is divided into eight 8 Block Pairs each containing two 2 Blocks making 16 Blocks per Frame Messages larger than the 1518 byte IP limit are broken down into multiple IP packets for transmission Use the following formula to determine the average bandwidth required over a given time period bps the number of bits per second b s bps Bx8 B the number of bytes of interest 8 the number of bits per byte t the time period in seconds In the I2E configuration a request for data is sent from the Exporter to the Importer A response containing the requested data is then sent from the Importer to the Exporter and the data is placed into its respective logical channels When needed the Exporter makes its next request for data In the E2X mode data is sent from the Exporter to the Exciter at a predetermined Block Block Pair and or Frame rate Within each PDU is one of the following messages e P1 logical channel is considered the Core channel lt can convey 48 96 kb s and always carries the MPS and also carries SIG data if Advanced Application Services are present P1 may also be configured to carry one or more supplemental programs or data services P1 is sent at the Frame rate e P2 logical channel is used only for all digital modes e P2j3 logical channe
66. nel P3 P1 is handled exactly the same as it was for MP1 In Block Zero 0 an additional 64 byte request is made for the P3 data and the Importer responds with an additional 440 byte message The P3 request and response is repeated at the block pair rate every 185 milliseconds over the entire frame For detailed information on the structure and timing of the MP2 I2E UDP data frames see the following tables in the Appendix Table 9 Service Mode MP2 GE UDP Data Frame Structure SPS1 at 12 kb s on P3 Table 10 Service Mode MP2 GE UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 Table 11 Service Mode MP2 GE UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 Doc No TX_TN_ 2040 Page 15 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 3 3 3 MP3 I2E UDP Data Frame Structure MP3 makes 24 kb s of bandwidth available for supplemental services through logical channel P3 P1 is still handled the same as for MP1 and MP2 P3 functions the same as in MP2 except that the block pair rate PDU is larger In Block Zero 0 the request is made for the P3 data and the Importer responds with a 729 byte P3 message The P3 request and response is repeated at the block pair rate of 185 milliseconds over the entire frame For detailed information on the structure and timing of the MP3 I2E UDP data frames see the following tables in the Appendix Table 12 Se
67. nking to use on the port Dynamic Trunking Protocol DTP provides this ability to negotiate the trunking method with the other device The precursor to DTP is a protocol named Dynamic Inter Switch Link Protocol or DISL Protocol If these protocols run they can delay when a port on the switch becomes active Usually a port that connects to a workstation belongs to only one VLAN Therefore the port does not need to trunk If a port has the ability to negotiate the formation of a trunk the port usually defaults to the auto mode If you change the port trunking mode to off you can further reduce the delay of when a switch port becomes active 4 3 5 Speed and Duplex Negotiation Speed and duplex negotiation detects the speed 10Mbps and 100Mbps for examples and the signal flow direction setting half duplex or full duplex of the device on the other end of the wire and subsequently adjusts to match those settings During speed and duplex negotiation the device transmits its own abilities to the peer device so that the peer can use the appropriate settings When configuring devices and switch ports a general rule of thumb is that for any given port both sides of the connection should have their duplex and speed set manually or both sides should have their speed and duplex set to auto negotiate which is in almost all cases the factory default setting 4 3 6 Limiting Other Extraneous Traffic Any traffic that switches forward to
68. ntial congestion resulting in packet loss caused by peak burst traffic Table 5 in the Appendix gives an indication of the HD Radio network dropouts that may be expected using UDP without error correction In order for an HD Radio data network using a TCP data stream to function properly even under adverse conditions the STL WAN link that carries it must have reserve bandwidth above and beyond the data rate of the stream This is necessary to accommodate the higher data rate that occurs when the stream recovers from lost packets With TCP and 20 frames of buffering so long as the average data stream rate occupies less than 60 of the link s bandwidth the HD Radio data stream can tolerate up to 1 packet loss and at least 80 milliseconds of latency although this would be considered an unhealthy network e A Healthy WAN link has a packet loss of less than 0 1 e A Marginal WAN link has a packet loss of less than 1 e An Unhealthy WAN link has packet loss of greater than 1 5 3 2 Bandwidth Provisioning Bandwidth is the term used to denote the data carrying capacity of a network link Bandwidth is usually expressed in bits per second or in terms of the designation of a link such as T1 E1 DSO or OC24 Each one of these designations corresponds to a specific data rate expressed in bits per second Utilization is the level of a link s carrying capacity that is in use and is expressed either as a percentage of the link s bandwidth or in bits per
69. onds consider this a problem 5 3 4 Network Jitter Network jitter is a variation in packet transit delay caused by queuing contention serialization effects and disparately clocked devices on the path through the network Jitter is more likely to occur on either slow or heavily congested links Jitter usually refers to packet delivery variations of 100 msec or less and jitter frequencies above 1 Hz All networks will have some jitter Typical network jitter ranges between 600 us and 10 ms though 100 ms and higher is not uncommon particularly over an STL circuit The use of Quality of Service QoS control mechanisms and higher speed links reduces the incidence of jitter related problems but does not eliminate them entirely Jitter is normally only an issue in real time or near real time applications where data is immediately acted upon and receive buffers are very small or non existent where the slight variations in data timing would cause data to overflow or underflow In E2X excessive jitter would result in lost audio frames dropped audio and a subsequent slip in the diversity delay timing The ample receive buffering used in the Exgine however is more than sufficient to overcome any realistic amount of network jitter The use GPS as timing reference on both Exporter and Exgine eliminates this issue For HD Radio over E2X without GPS lock network jitter should still be maintained as low as possible to avoid blatantly noticeable blending art
70. or either IBOC application scenario In fact stations may elect to deploy the present platform with 44 1 kb s for the AES digital audio and 80 kb s for LAN connectivity In the future they may adopt the Exporter platform and simply reconfigure Starlink for 32 kb s for the AES digital audio and 512 kb s for the LAN data as shown in Table 2 for example Starlink s open architecture allows for future upgrades and reconfiguration to react to changing transport requirements 5 1 4 T1 E1 on a 5 8 GHz Bidirectional Radio Link Digital soread spectrum radios offer a solution to stations preferring the benefits of an RF STL with all the payload capabilities of a T1 system In a spread spectrum radio system the leased wired T1 line is replaced by a T1 2 4 GHz or 5 8 GHz bidirectional radio link Spread spectrum T1 radios are used by major telephone companies as the last mile to extend their networks into areas well beyond the reach of wired facilities Spread spectrum radio use was originated by the military because of its robustness and security The spread spectrum signal is spread over a much wider bandwidth than needed to transport the information using a unique spreading code The receiver with the same code can recover the information in the presence of very low signal to noise ratios This also reduces or eliminates the effects of interference which tends to be fixed frequency For this reason spread spectrum systems perform over greater d
71. rred to as the five nines Link availability A is defined as follows A uptime uptime downtime We also often speak in terms of unavailability U defined as follows U 1 A So 99 999 availability translates to 0 001 1 0 99999 unavailability or about 6 seconds of outage per week 5 minutes per year For STL links a practical value of 99 9 availability for the worst month is the minimum used This comes out to 10 minutes of outage per week during the worst month For line of sight links the fading probability availability and conversely the unavailability are related to a modified Rayleigh probability distribution defined by industry accepted methods Vigants Barnett KO Factor and ITU R P 530 6 through P 530 9 Path calculation software such as Pathloss 4 0 from Contract Telecommunication Engineering implements these equations rather painlessly to aid system planning 5 3 7 Bit Error Rate Bit error rate BER is the percentage of bits that have errors relative to the total number of bits received in a transmission usually expressed as ten to a negative power For example a transmission might have a BER of 10 meaning that out of 1 000 000 bits transmitted one bit was in error The BER is an indication of how often a packet or other data unit has to be retransmitted because of an error Too high a BER may indicate that a slower data rate would actually improve overall transmission time for a given amount of
72. rvice Mode MP3 GE UDP Data Frame Structure SPS1 at 24 kb s on P3 Table 13 Service Mode MP3 GE UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 Table 14 Service Mode MP3 GE UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 3 3 4 TCP Implementation of I2E The TCP implementation of the I2E protocol is nearly identical to the UDP implementation At the beginning of the frame the Importer makes a request for data to the Exporter The Importer responds by sending the requested data to the Exporter The Exporter responds with acknowledgement of the data that each IP packet was received If there is a discrepancy the missing data will be resent This is a function of the TCP transport Additional receive buffering in the Exporter allows time for retransmission of the missing packets For detailed information on the structure and timing of the TCP data frames for all service modes see the following tables in the Appendix Table 15 Service Mode MP1 I2E TCP Data Frame Structure SPS1 at 12 kb s on P1 Table 16 Service Mode MP1 I2E TCP Data Frame Structure SPS1 at 32 kb s on P1 Table 17 Service Mode MP1 I2E TCP Data Frame Structure SPS1 at 48 kb s on P1 Table 18 Service Mode MP2 DE TCP Data Frame Structure SPS1 at 12 kb s on P3 Table 19 Service Mode MP2 GE TCP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 Table 20 Serv
73. sioning by Service Mode 38 Table 5 Prediction of HD Radio data network dropouts due to network packet osses aaa a kana a akanai a 39 Table 6 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 12 kb s onbe 42 Table 7 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 32 kb s onbe 43 Table 8 Service Mode MP1 I2E UDP Data Frame Structure SPS1 at 48 kb s onbe 44 Table 9 Service Mode MP2 I2E UDP Data Frame Structure SPS1 at 12 kb s on P3 a a 45 Table 10 Service Mode MP2 I2E UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 12 kb s on P3 46 Table 11 Service Mode MP2 I2E UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 12 kb s on P3 47 Table 12 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 24 kb s on P3 48 Table 13 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 32 kb s on P1 and SPS2 at 24 kb s on P3 49 Table 14 Service Mode MP3 I2E UDP Data Frame Structure SPS1 at 48 kb s on P1 and SPS2 at 24 kb s on P3 50 Table 15 Service Mode MP1 12E TCP Data Frame Structure SPS1 at 12 kb s on P1 51 Table 16 Service Mode MP1 12E TCP Data Frame Structure SPS1 at 32 kb s on P1
74. te in terms of performance and bandwidth However in high RF environments these inexpensive home office switch units may be susceptible to packet losses due to RF Doc No TX_TN_2040 Page 21 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements interference if proper grounding and installation practices are not observed Shielded Category 6 cabling along with other proper RF shielding and grounding techniques may be required and should be implemented as a matter of good engineering practice 4 2 2 Criteria for Switch Selection For the switches located at the studios Manageability SNMP v2 support Interface statistics VLAN support for broadcast isolation 802 1Q trunking support 802 1D Spanning Tree Protocol STP or 802 1W Rapid Spanning Tree Protocol RSTP Support Layer 2 switching Layer 3 routing Security 10 100 Mbps wire speed switching routing Appropriate units are Cisco Catalyst 3560 24 TS L2 L3 Cisco Catalyst 3750 24TS L2 L3 Cisco Catalyst 4507R L2 L3 Enterprise switch HP Procurve 3400 Series Nortel 3510 Series For the switches located at the transmitter e 10Mbps wire speed switching routing Ten megabits per second is more than adequate since the different service modes in the HD Radio system never exceed 512 kb s e RF immunity Appropriate units are e Linksys EtherFast Cable DSL Router with 4 Port Switch BEFSR41 e D Link 5 port 10 100 Desktop Switch DES 1105 e
75. th are the two factors that determine your network speed and robustness All digital networks have latency and packet loss These phenomena when they are excessive can interfere with the transmission of data particularly streamed data In streams using TCP when packets in a stream are lost in transit the stream momentarily stops to recover the lost data The amount of time it takes to recover the lost data is governed largely by the link s latency When the lost data is recovered the data stream usually has to catch up by transmitting data at a higher than normal rate If packet loss is infrequent and the link s latency is low the stream can easily recover As packet loss and or latency climbs the recovery process cannot as easily catch up and at some point packet loss and latency combine so that the buffers in the receiving device dwindle When the buffers are depleted the application depending on the data stream suffers a loss or degradation of service that is noticeable to the user e Good WAN latency is 30 milliseconds or less e Reasonable WAN latency is between 30 and 70 milliseconds e Poor WAN latency is between 70 and 120 milliseconds Be sure to measure latency across a WAN link under load using a standard 64 byte ping test of at least 10 iterations Use the minimum value returned as an approximate measure of the link latency If it is below 50 milliseconds disregard latency as a source of problems If it is higher than 100 millisec
76. ther physical disruption or excessive packet losses Reestablishing the connection in Version 2 3 3 requires a manual reboot of both the Exporter and Exciter Because of this use of the TCP protocol for E2X is generally not recommended Doc No TX TN 2040 Page 9 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements Lab test results for the E2X configuration running UDP revealed that IP packet loss must be better than 10 for a successful implementation It is not uncommon for wide area networks and STL systems considered healthy to deliver only 10 performance or one dropped packet in every 1000 which will result in very poor HD Radio system performance Table 5 in the Appendix predicts the number of HD Radio dropouts that can be expected for a given network packet loss based on the number of packets sent per day when running UDP without error mitigation Without error correction or mitigation we can expect from 6 to 31 momentary dropouts per day depending on the mode and configuration when using UDP over a 10 link The unsupported TCP implementation of E2X faired considerably better than UDP It was determined that this configuration could successfully tolerate packet losses of up to 0 03 This level of performance is well within the capabilities of healthy WAN STL systems E2X average bandwidth utilization ranges between 120 kb s and 168 kb s depending on the configuration and IP protocol used AWAN STL band
77. tions with a common set of requirements that may be independent of physical location VLANs have the same attributes as a physical LAN but allow you to group end stations even if they are not located physically on the same LAN segment VLANs are associated with IP sub networks All the end stations in a particular IP subnet belong to the same VLAN Traffic between VLANs must be routed Port VLAN membership on the switch is assigned manually on a port by port basis When you assign switch ports to VLANs using this method it is known as port based or static VLAN membership At minimum when creating a new VLAN you must set these parameters VLAN number VLAN name Switch ports assigned to the VLAN The numbers used should be in the 400 599 data center devices range Check with your IT department The name is whatever name you choose to refer to this VLAN e The ports are the physical ports on the switch or router These are referred to by interface port number A router or switch may have multiple interfaces Consult your particular switch s user manual for specific guidance on configuring VLANs 4 3 2 Monitoring Ports lt is often advantageous to be able to monitor the traffic on a specific switch port such as the port connected to the STL WAN system with a packet analyzer like EtherPeek The Switched Port Analyzer SPAN feature available on many managed switches sometimes called port mirroring or port monitoring selects network tr
78. to the Exporter which splits the audio into two streams One is sent to the analog audio processing chain and one is sent to the digital processing chain Both streams are returned to the Exporter after processing The audio destined for the legacy analog transmitter is time aligned with the digital and sent to the AES digital input of the STL for transport to the legacy analog transmitter The main HD Radio program audio is encoded into the MPS signal Meanwhile the Importer accepts data and audio inputs of the Multicast programs These services are encoded and sent from the Importer to the Exporter over a local network as bidirectional UDP or TCP data over Ethernet as in the I2E configuration discussed in Section 2 1 The Main Program Service and the Advanced Services SPS and data are then combined in the Exporter into a single data stream destined for the Exciter over the STL or WAN link Studio to transmitter transport of the E2X data stream is currently supported only as simplex one way UDP and can operate over most unidirectional STL systems of sufficient bandwidth and robustness Included in Version 2 3 3 is provision for E2X over TCP requiring a bidirectional link however the TCP connection is not fully supported in the iBiquity Reference Exporter Version 2 3 3 Different manufacturers may or may not add this support in their implementations The unsupported TCP service has no mechanism to reestablish the connection should it be broken by ei
79. ts 6 2 12E Exporter Receive Buffer Monitoring The Exporter maintains twenty 1 48 second frames worth of PDUs resulting in approximately 30 seconds of delay to allow sufficient time for TCP retransmissions required due to dropped IP packets The status of these buffers is a good indication of the performance of the network and a predictor of HD AAS outages The procedure for monitoring the Exporter s receive buffers as discussed in Section 2 2 is as follows 1 Set the Exporter I2smxtx x logging level to 2 2 Press F12 to open a console window or telnet into the Exporter 3 Type tail f mnt data irss log grep PDUs Lroot hawthorn tx tail f mt data irz loglgrep PIs 14 45 11 476 N 1Zzmxta 14 46 11 477 Nr Zens 14 46 12 864 Nr 123smx 14 47 15 3821 Ni lams 14 45 05 813 Nr 12zmx 14 54 47 163 Ni Leste 15 02 54 16 Nr 12smx 15 02 54 6055 H l2amx 15 02 561139 Ni 12zmx 15 02 571025 Ni 123smx l2smxtdo ct 2123 New High Water PDLs 1 in fifa gt 20 l2smxtdo c 2619 Mew Low Water PDUs 1 in fifo gt 19 2smxtdo c 21231 New High Water PIUs 1 in fifo gt 21 2smxtdo c 2513 New Low Water PIUs 1 in fifo gt 19 Ssmxtdo ct 2513 Neu Low Water PIUs 1 in fifo gt 18 2smxtdo c 2619 New Low Water PIUs 1 in fifa gt 17 lZ smxtdo ct 2123 New High Water PDUs 1 in fifo gt 1i l2smxtdo ct 21234 New High Water FIUs 1 in fifa gt 1 l2smxtdo ct 2123 New High Water PIUsl1 in fifa gt
80. width of at least 128 kb s with latency of less than 100ms is necessary for MP1 mode UDP Here too a 128 kb s LAN WAN Extender or two 2 DSOs will provide sufficient bandwidth for any MP1 configuration For MP3 256 kb s or 4 DSOs should be considered for UDP and 320 kb s or five 5 DSOs should be more than sufficient for TCP For more information on provisioning for various configurations and expected losses due to bit error rates see Table 4 Data Rates and Provisioning by Service Mode With UDP Packet loss across the link becomes a Critical factor and must be kept below 10 for successful operation due to a lack of error recovery See Table 5 Prediction of HD Radio data network dropouts due to network packet losses BEE Doc No TX TN 2040 Page 10 Rev 09 iBiguity Digital Corporation HD Radio Data Network Requirements 2 2 1 One Exporter to Multiple Exciters Configuration It is possible to connect two or more Exciters to a single Exporter This might be desirable for operating translator stations or for supporting main and backup transmitter sites Currently the only option for this configuration is to set the Exporter to send its data as an IP broadcast within the HD Radio subnet Figure 4 shows the Single Exporter to Multiple Exciters configuration Studio Site TX Site 1 IP 192 168 10 1 STL E vciter STL STL At STL BAS WW L3 Switch T

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