Cisco Systems uBR7246 User's Manual
Contents
1. Configuring Cisco UBR7246 Universal Broadband Router Features Cisco uBR7246 universal broadband features enable the Cisco uBR7246 universal broadband router to communicate with a hybrid fiber coaxial HFC cable network via a Cisco MC11 cable modem card Cisco MC11 cable modem cards allow you to connect cable modems on the HFC network to a Cisco uBR7246 in a Community Antenna Television CATV headend facility The modem card provides the interface between the Cisco uBR7246 protocol control information PCI bus and the radio frequency RF signal on the HFC network For a description of the commands used to configure universal broadband features refer to the Cisco uBR7246 Universal Broadband Features Commands chapter in the Voice Video and Home Applications Command Reference The MC11 cable modem cards consist of the following components One downstream cable F connector port The downstream port supports quadrature amplitude modulation QAM speeds of 64 QAM or 6 bits per symbol A symbol is the basic unit of modulation in CATV systems One upstream cable F connector port The upstream port supports quadrature phase shift keying QPSK modulation or 2 bits per symbol Cable Media Access Control MAC unit The cable MAC frames and encrypts the downstream signal for RF transmission and passes the signal to the downstream physical layer PHY Reverses the signal framing and encryption on the upstream signal from the up2. Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure that you have entered the correct upstream port number Currently this is always u0 Activate the Upstream Scrambler The scrambler on the upstream RF carrier enables cable modems on the HFC network to use built in scrambler circuitry for upstream data transmissions The scrambler circuitry improves reliability of the upstream receiver on the cable modem card The upstream scrambler is activated by default and should not be disabled A Caution The Scrambler must be activated for normal operation Deactivate only for prototype modems that do not support scrambler To activate the upstream scrambler use the following command in cable interface configuration mode Command Purpose cable upstream port scrambler Enable the scrambler Configuring Cisco uUBR7246 Universal Broadband Router Features VC 147 Configure the Upstream Cable Interface Validation Tips Troubleshooting Tips To verify if the upstream scrambler is activated enter the command more system running config and look for the cable interface configuration information The following is an excerpt from the more system running config command output router more system running config Building configuration C
3. A or Annex B setting enter the show controllers cable command for the downstream port that you have just configured router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure you have selected the correct setting for your location Make sure the downstream carrier is active by entering the cable downstream if output command Set the Downstream Modulation Downstream modulation is the number of symbols per second by setting the downstream modulation you define the speed at which data travels downstream to the user which is 64 qam 6 bits per downstream symbol rate Note The Cisco cable modem cards currently do not offer a downstream modulation setting for 256 QAM 8 bits per downstream symbol rate Configuring Cisco uBR7246 Universal Broadband Router Features VC 141 Configure the Downstream Cable Interface Validation Tips To set the downstream modulation use the following command in cable interface configuration mode Command Purpose cable downstream modulatio
4. Backoff End 4 Tx Backoff Start 0 Tx Backoff End 4 Modulation Profile Group 1 part_id 0x3136 rev_id 0x02 rev2_id 0x61 nb_agc_thr 0x0100 nb_agc_nom 0x3000 Range Load Reg Size 0x58 Request Load Reg Size 0x0C Minislot Size in number of Timebase Ticks is 8 Minislot Size in Symbols 64 Minislot Size in Bytes 16 UCD Count 361894 DES Reg 580 E204301 584 3E030303 588 0 590 COCOCOC Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure that you have entered the correct upstream port number Currently this is always u0 Make sure you have selected a valid frequency for your headend Set the Upstream Input Power Level A The Cisco uBR7246 controls the output power levels of the cable modems to meet the desired upstream input power level The default setting of 0 dBmV is the optimal setting for the upstream power level Caution If you increase the input power level the cable modems on your HFC network will increase their transmit power level This might cause an increase in the carrier to noise ratio CNR on the network Be careful if you adjust this parameter You might violate the upstream return laser design parameters To set the upstream input power
5. and configuring the 1OOBASE T Fast Ethernet port adapter refer to the OOBASE T Fast Ethernet Port Adapter Installation and Configuration document For information about installing and configuring the ATM port adapter refer to the ATM Port Adapter Installation and Configuration document For information about installing and configuring the HSSI port adapter refer to the HSSI Port Adapter Installation and Configuration document Configuring Cisco UBR7246 Universal Broadband Router Features VC 137 Configure the Downstream Cable Interface Install at least one Cisco MC11 cable modem card in the appropriate slot of Cisco uBR7246 chassis For information about installing the Cisco MC11 cable modem card refer to the Cisco uBR7246 Universal Broadband Router Cable Modem Card Installation and Configuration document Supported MIBs and RFCs The Cisco uBR7246 universal broadband features support the RF Interface Management Information Base MIB No RFCs are supported by this feature Universal Broadband Features Configuration Task List The Cisco IOS software command line interface CLI is used to configure the Cisco MC11 cable modem card for correct operation on the HFC network Perform the following tasks to configure the MC11 cable modem card For some tasks the default values are adequate to configure the device these configuration tasks are optional Configure the Downstream Cable Interface Optional Configure the Upstr
6. level use the following command in cable interface configuration mode Command Purpose cable upstream port power level dbmv Enter the upstream power level in dBmV Configuring Cisco UBR7246 Universal Broadband Router Features VC 145 Configure the Upstream Cable Interface Validation Tips Troubleshooting Tips To verify the current value of the upstream input power level enter the show controllers cable command for the upstream port that you have just configured router show controllers cable 6 0 u0 Cable6 0 Upstream 0 is up Frequency 7 008 MHz Channel Width 1 6 MHz QPSK Symbol Rate 1 280 Msps Nominal Input Power Level 0 dBmV Tx Timing Offset 0 Ranging Backoff Start 0 Ranging Backoff End 4 Tx Backoff Start 0 Tx Backoff End 4 Modulation Profile Group 1 part_id 0x3136 rev_id 0x02 rev2_id 0x61 nb_agc_thr 0x0100 nb_agc_nom 0x3000 Range Load Reg Size 0x58 Request Load Reg Size 0x0C Minislot Size in number of Timebase Ticks is 8 Minislot Size in Symbols 64 Minislot Size in Bytes 16 UCD Count 361894 DES Reg 580 E204301 584 3E030303 588 0 590 COCOCOC If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure that you have entered the correct upstream port numbe
7. 0 series router with the high speed network access of a Cable Modem Termination Shelf CMTS By combining these two essential functions the Cisco uBR7246 router conserves valuable headend rack space and it allows cable operators to deploy routing capability in every CMTS location which improves network performance Configuring Cisco UBR7246 Universal Broadband Router Features VC 135 List of Terms Providing a universal platform for deployment of both current and future modem technologies via modular upgrades while protecting the operator s invested capital Leveraging Cisco s industry standard routing hardware and Cisco IOS software to deliver advanced network services and applications The Cisco uBR7246 uses the same port adapters as the Cisco 7500 and Cisco 7200 series routers and they are fully interchangeable This adaptability and flexibility allows the operator to configure the network with any interface desired including Ethernet Fast Ethernet FDDI ATM packet over SONET and serial The Cisco uBR7246 cable modem cards are fully compatible with the Data Over Cable System Interface Specification DOCSIS established by major North American cable operators through the Multimedia Cable Network System MCNS consortium The Cisco uBR7246 supports both two way and telephone return modems on a single downstream channel The Cisco uBR7246 therefore allows both one way and two cable plants to provide cable modem service and
8. Hz Symbol Phase range of a sine wave Upstream Frequency multiplexed band in a CATV channel that distributes signals from transmitting stations to headend In this instance upstream refers to the data flow from a cable modem to the Cisco MC11 modem card in a Cisco uBR7246 VC 136 Voice Video and Home Applications Configuration Guide List of Terms Prerequisite Tasks Before you can configure Cisco uBR7246 universal broadband router features you must first Make sure that your current network is designed to support broadband transmission At the very least your network must include the following Computer on the WAN side of your Cisco uBR7246 configured as a DHCP server to assign IP addresses to cable modems on the HFC network Cisco uBR7246 compatible IF to RF upconverter installed in the downstream data path at your headend site The upconverter is installed between the Cisco uBR7246 and the combiner Note The combiner refers to all cables amplifiers and taps at the headend or cable distribution center that connect the Cisco uBR7246 to the hybrid fiber coaxial HFC network Diplex filters installed in the downstream RF path between the cable modems and the cable modem cards in the Cisco uBR7246 Diplex filters are used to convert the single bidirectional signals used by cable modems to the two separate unidirectional signals used by the cable modem cards RG 59 headend coaxial cable with t
9. ant To configure and activate baseline privacy perform the following tasks Configure Kek Encryption Key Privacy Configure Traffic Encryption Key Privacy Activate Baseline Privacy Configure Kek Encryption Key Privacy To configure kek data privacy on the HFC network use one of the following command in global configuration mode Command Purpose cable privacy kek grace time seconds Set the cable privacy kek grace time or or cable privacy kek life time secods Set the cable privacy kek life time A grace time kek can be set from 300 to 1 800 seconds A life time kek can be set from 86 400 to 6 048 000 seconds Validation Tips To verify the kek life time or grace time values that have been set enter the show cable privacy kek command router show cable privacy kek Configured KEK life time value 750000 Troubleshooting Tips If you are having trouble make sure you have entered a valid value for grace time or life time Configure Traffic Encryption Key Privacy To configure tek data privacy on the HFC network use the following command in global configuration mode Command Purpose cable privacy tek grace time seconds Set the cable privacy tek grace time or cable privacy tek life time seconds Set the cable privacy tek life time A grace time tek can be set from 300 to 1 800 seconds A life time tek can be set from 1 800 to 604 800 seconds VC 150 Voice Video and Home Applications Configura
10. ate for a downstream port on a cable modem card A symbol is the basic unit of modulation QPSK encodes 2 bits per symbol 16 QAM encodes 4 bits per symbol 64 QAM encodes 6 bits per symbol and 256 QAM encodes 8 bits per symbol The valid range for the downstream symbol rate is 0 to 6 000 000 Msps Caution The default downstream symbol rate is set to comply with MCNS specifications for Annex B cable modem support at 5 056941 Msps with 64 QAM modulation and 5 36037 Msps with 256 QAM modulation This command should only be used to change the symbol rate to support Annex A cable modems that are used outside North America To set the downstream symbol rate use the following command in cable interface configuration mode Command Purpose cable downstream symbol rate number Set the downstream symbol rate for Annex A 5 056944 Msps Do not enter the decimal point in the symbol rate To verify the downstream symbol rate enter the show controllers cable command for the downstream port that you have just configured router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you hav
11. cies Valid frequencies are 5 000 000 to 42 000 000 Hz and valid power levels are 10 dBmV to 10 dBmV The power level value should only be changed if you want to change only the power level as part of spectrum management The standard power level is 0 dBmV Note You must repeat this command for each frequency or power level that you want to add to a spectrum group s list of valid values To configure and activate a spectrum group use the following command in global configuration mode Command Purpose cable spectrum group group number time hh mm ss Add the upstream frequency to the list of frequency number power level dbmv valid frequencies with a default power level for a spectrum group To verify if spectrum groups have been configured and activated enter the show cable spectrum group command router show cable spectrum group spectrum group 1 6 500 MHz 0 dBmV input level 7 000 MHz 0 dBmvV input level spectrum group 2 7 500 MHz 5 dBmV input level spectrum group 3 9 000 MHz 0 dBmV input level 9 500 MHz 5 dBmV input level Troubleshooting Tips If you are having trouble make sure you entered a valid spectrum group number time frequency and input power level Activate IP Address Resolution Protocol Address Resolution Protocol ARP is an Internet protocol used to map IP addresses to MAC addresses on computers and other equipment installed in a network You need to activate ARP requests so th
12. configure the Cisco uBR7246 Set the Downstream Center Frequency Validation Tips You need to set the downstream frequency of your RF output to comply with the expected input frequency of your upconverter To do this enter the fixed center frequency of the downstream RF carrier for a downstream port Downstream frequency is an information only command that should reflect the digital carrier frequency which is the center frequency of the downstream RF carrier the channel for that downstream port The configuration controlling the digital carrier frequency is done in the IF to RF upconverter that must be installed in the downstream path from the Cisco uBR7246 Refer to the upconverter s manufacturer s instructions for information about configuring the upconverter The digital carrier frequency is specified to be the center of a 6 0 MHz channel For example EIA channel 95 spans 90 000 to 96 000 MHz The center frequency is 93 000 MHz which is the digital carrier frequency that should be configured as the downstream frequency Note The digital carrier frequency is not the same as the video carrier frequency For EIA channel 95 the video carrier frequency is 91 250 MHz which is 1 75 MHz below the center frequency Note This command currently has no effect on external upconverters it is informational only To set the downstream center frequency use the following command in cable interface configuration mode Comman
13. d Purpose cable downstream frequency down freq hz Enter the fixed center frequency for your downstream RF carrier in Hz To verify the current value of the center frequency enter the show controllers cable command for the downstream port that you have just configured If the center frequency is fixed the actual frequency will be displayed router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 If the center frequency is not fixed the frequency will show that it is not set router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency is not set Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 Configuring Cisco UBR7246 Universal Broadband Router Features VC 139 Configure the Downstream Cable Interface Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure you have calculated and entered the center frequency for your headend accurately Set the Downstream Symbol Rate A Validation Tips You need to set the megasymbols per second Msps r
14. downstream interleave depth setting enter the show controllers cable command for the downstream port that you have just configured router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J VC 142 Voice Video and Home Applications Configuration Guide Activate the Downstream Carrier Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure the downstream carrier is active by entering the cable downstream if output command Activate the Downstream Carrier To activate a downstream port on a cable modem card for digital data transmissions over the HFC network use the following commands in global configuration mode Step Command Purpose 1 interface cable port slot Specify a cable interface and enter the cable interface configuration mode 2 cable downstream if output Activate downstream digital data from the Cisco uBR7246 This is the default setting Validation Tips To verify that the downstream carrier is active up enter the show controllers cable command for the downstream port that you have just configured router
15. e Cisco uBR7246 can perform IP address resolution on the downstream path Note The default values for the commands used in this configuration step are in most cases adequate to configure the Cisco uBR7246 Configuring Cisco UBR7246 Universal Broadband Router Features VC 153 Activate Host to Host Communication Proxy ARP Activate Address Resolution Protocol Requests Validation Tips To activate ARP requests use the following command in cable interface configuration mode Command Purpose cable arp Enable ARP To verify if ARP has been activated enter the command more system running config and look for the cable interface configuration information If ARP has been activated it does not appear in this output If ARP has been deactivated it will appear in the output as no cable arp as shown in this command output excerpt router more system running config Building configuration Current configuration interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive no cable arp cable insertion interval 150000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure you entered the correct port and modem card slot number when you activated ARP a
16. e entered the correct slot and port numbers when you typed the command Make sure you have selected the default if you are using Annex B cable modems Make sure that you have entered the correct symbol rate for Annex A specifications if you are using Annex A cable modems Do not enter the decimal point when entering the symbol rate Make sure the downstream carrier is active by entering the cable downstream if output command VC 140 Voice Video and Home Applications Configuration Guide Set the Downstream MPEG Framing Format Annex A or Annex B Set the Downstream MPEG Framing Format Annex A or Annex B The MPEG framing format must be compatible with the downstream symbol rate you set Set the MPEG framing format for a downstream port on a cable modem card to either Annex A or Annex B Annex B is the North America standard and Annex A is the European standard You should review your local standards and specifications for downstream MPEG framing to determine which format you should use Note The cable modem card downstream ports and the cable modems on the HFC network connected through these ports must be set to the same MPEG framing format To set the downstream MPEG framing format use the following command in cable interface configuration mode Command Purpose cable downstream annex A B Set the downstream MPEG framing format Validation Tips To verify the downstream MPEG framing format Annex
17. eam Cable Interface Configure and Activate Baseline Privacy Configure and Activate Frequency Agility Activate IP Address Resolution Protocol Optional Activate Host to Host Communication Proxy ARP Optional Set Optional IP Parameters Optional Manage Cable Modems on the HFC Network Optional Configure the Downstream Cable Interface The first step in configuring the MC11 cable modem interface is to configure the downstream cable interface In this case downstream refers to the data flow from the Cisco MC11 modem card ina Cisco uBR7246 to the user s cable modem Data passing through the MC11 cable modem card is converted to IF and then run through an upconverter to transform the signal to RF This RF signal is then sent down the line to the user s cable modem Downstream cable interface commands configure the frequency symbol rate compression and modulation of the downstream signal Perform the following tasks to configure the downstream cable interface Set the Downstream Center Frequency Set the Downstream Symbol Rate Set the Downstream MPEG Framing Format Annex A or Annex B Set the Downstream Modulation Set the Downstream Interleave Depth Activate the Downstream Carrier VC 138 Voice Video and Home Applications Configuration Guide Set the Downstream Center Frequency Note The default values for the commands used in these configuration steps are in most cases adequate to
18. ed with other analog TV or digital TV signals and sent to the transmit input of a fiber transceiver The receive input of the fiber transceiver is connected to an upstream port of the Cisco uBR7246 The upstream port is assigned a 0 2 3 2 MHz frequency band in the reverse plant In North America carrier frequencies in the reverse plant are between 5 42 MHz The fiber transceiver is connected to up to 80 kilometers of optical fiber Signals are carried in analog form to a neighborhood where they terminate in a fiber node The fiber node located on a telephone pole or in an underground box converts the optical signal back to an electrical signal which is passed on to a two way distribution amplifier system The distribution amplifier system passes through the neighborhood where it is tapped off to individual CATV subscribers Typically there are 500 1500 homes passed per fiber node A coaxial cable delivers the signal from the tap to a subscriber s drop box From the drop box the signal is split and cabled to consumer CATV appliances In addition to analog or digital television the subscriber obtains data services using a cable modem appliance like the Cisco uBR904 cable modem Benefits of Cisco uBR7246 The Cisco uBR7246 features bring value to the digital broadband network by Enabling the cost effective deployment of advanced routing capabilities deep into the cable network Combining the power and functionality of a Cisco 720
19. er the show interface cable command for the upstream port that you have just configured router show interface cable 6 0 Cable6 0 is up line protocol is up Hardware is BCM3210 FPGA address is 00e0 1le5f 7a60 bia 00e0 1e5f 7a60 Internet address is 1 1 1 3 24 MTU 1500 bytes BW 27000 Kbit DLY 1000 usec rely 255 255 load 1 255 Encapsulation loopback not set keepalive not set ARP type ARPA ARP Timeout 04 00 00 Last input 00 00 25 output 00 00 00 output hang never Last clearing of show interface counters never Queueing strategy fifo Output queue 0 40 0 drops input queue 0 75 0 drops 5 minute input rate 0 bits sea 0 packets sec 5 minute output rate 0 bits sec 0 packets sec 10878 packets input 853740 bytes 0 no buffer Received 3679 broadcasts 0 runts 0 giants 0 throttles 3 input errors 3 CRC 0 frame 0 overrun 0 ignored 0 abort 5401 packets output 645885 bytes 0 underruns 0 output errors 0 collisions 9 interface resets 0 output buffer failures 0 output buffers swapped out Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure that you have entered the correct upstream port number Currently this is always u0 Configure and Activate Baseline P
20. excerpt router more system running config Building configuration Current configuration I interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive cable insertion interval 2000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure that you entered the correct slot and port numbers when you typed the command Universal Broadband Features Configuration Example Most of the default values for the commands described in this document are adequate to configure the Cisco uBR7246 The following example shows the minimum configuration necessary to enable this feature Enter the global configuration mode configure terminal l Enter the cable interface configuration mode This example shows that the Cisco MC11 card is in the 6th slot or bottom slot of the Cisco uBR7246 chassis interface cable 6 0 l Configure the upstream data frequency In this example for channel 0 the frequency is 15 800 MhZ or 15 800 000 Hz cable u0 1580000 Enable cable interface no cable upstream 0 shutdown I Enable router interface no shutdown Set interface s IP address ip address lt ipaddr gt lt subnet mask gt end VC 160 Voice Video and Home Applicati
21. figure and activate frequency agility perform the following tasks Create Spectrum Groups Configure and Activate Spectrum Groups Create Spectrum Groups To create spectrum groups use the following commands in global configuration mode Step Command Purpose 1 cable spectrum group group number type blind Create a blind spectrum group 2 cable spectrum group group number type scheduled Create a scheduled spectrum group that daily can change its frequency and power level at the same time every day 3 cable spectrum group group number type scheduled Create a scheduled spectrum group that periodic sec seconds can change its frequency and power level at a specified interval in seconds Validation Tips To verify that a spectrum group has been created enter the show cable spectrum group command router show cable spectrum group spectrum group 1 spectrum group 2 spectrum group 3 Troubleshooting Tips If you are having trouble make sure you have entered a valid spectrum group number and type VC 152 Voice Video and Home Applications Configuration Guide Configure and Activate Spectrum Groups Configure and Activate Spectrum Groups Validation Tips After you create a spectrum group you need to configure a list of upstream frequencies and nominal power levels that each spectrum group can use when an upstream frequency change is necessary Each spectrum group should have its own list of upstream frequen
22. gives cable operators the flexibility to roll out service in systems that are only partially upgraded to two way List of Terms Community Antenna Television CATV Broadband transmission facility Downstream Frequency multiplexed band in a CATV channel that distributes signals from headend to users In this instance downstream refers to the data flow from the Cisco MC11 modem card in a Cisco uBR7246 to the user s cable modem Headend Originating point of a signal in a Cable TV system IF Intermediate frequency Intermediate electromagnetic frequencies generated by a superheterodyne radio receiver HFC Hybrid fiber coaxial cable Distribution cabling concept using both fiber optic and coaxial cable Fiber is used for the backbone distribution medium terminating in a remote unit where optoelectrical conversion takes place The signal is then passed as data to coaxial cables that carry it to its destination QAM Quadarture amplitude modulation Modulation technique that allows data encoded symbols to be represented in 16 or 32 different states QPSK Quaternary phase shift keying Compression technique used in modems and wireless networks allowing the transmission of 2 bits per symbol QPSK provides a 2 1 compression ratio resulting in double efficiency for the circuit being used RF Radio frequency Group of electromagnetic energy whose wavelengths are between the audio and light range usually between 500 KHz and 300 G
23. he maximum braid available 60 40 braid double foil and the correct connector for this cable The center conductor must be straight and extend 1 8 inch 3 2 mm beyond the end of the connector and the connector should be securely crimped to the cable Complete a basic configuration of the Cisco uBR7246 This includes as a minimum the following tasks Configure a host name and password for the Cisco uBR7246 For more information about how to configure a host name and password refer to the Cisco uBR7246 Universal Broadband Router Installation and Configuration Guide Configure the Cisco uBR7246 to support IP For more information about how to configure IP refer to the refer to the IP Overview Configuring IP Addressing and Configuring IP Services chapters in the Network Protocols Configuration Guide Part 1 Install and configure at least one port adapter to provide WAN connectivity The Cisco uBR7246 supports the following port adapters 4 port LOBASE T Ethernet 8 port 10BASE T Ethernet 1OOBASE T Fast Ethernet ATM and HSSI For information about installing and configuring the 4 port 1 OBASE T port adapter refer to the 4 E Ethernet 1 OBASE T Port Adapter Installation and Configuration document For information about installing and configuring the 8 port 1 OBASE T port adapter refer to the 8 E Ethernet 1OBASE T Port Adapter Installation and Configuration document For information about installing
24. i i I i l l l I I i l Digital TV AN Fiber signals l 9 W Transceiver Tan Sa a e a a a a S A a R E E eS ae J 80 km 1000 ft 7 N Fiber node Telephone pole ER f underground box Two way Drop box distribution gt amplifier gt gt gt _ gt gt Kg Tap Cable modem Cisco uBR904 VC 134 Voice Video and Home Applications Configuration Guide 11278 Description of Cisco uBR7246 Cable Router Description of Cisco uBR7246 Cable Router As shown in Figure 38 the Cisco uBR7246 serves as an interface between a WAN backbone and an HFC cable plant Typically installed at a CATV headend the Cisco uBR7246 is often located with the following internet service provider related components Ethernet switch Proxy server WAN Router The Ethernet switch is used to reduce traffic on the WAN backbone The proxy server usually functions as a Web cache for host computers and the DHCP TFTP server for cable modems DHCP for host computers in the HFC plant is often handled over the WAN The WAN router provides a gateway to the data network On the RF side the downstream port is assigned a 6 8 MHz channel slot at a standard broadcast CATV frequency An upconverter device is used to convert the 44 MHz intermediate frequency IF output to the assigned slot In North America carrier frequencies in the forward plant are assigned between 54 860 MHz After upconversion the signal is combin
25. iguration information as shown in this command output excerpt router more system running config Building configuration Current configuration interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive cabl cabl cabl cabl cabl cabl cabl cabl cabl Le e oooodo o e ip broadcast echo insertion interval 150000 downstream annex B downstream modulation 64qam downstream interleave depth 32 downstream symbol rate 5056941 upstream 0 frequency 15008000 upstream 0 fec upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure that you entered the correct slot and port numbers when you entered cable interface configuration mode Manage Cable Modems on the HFC Network After you have completed upstream and downstream signal configuration there are a number of different things you can do to manage how your cable modems operate in the HFC network You can control access by forcing cable modems to authenticate with the Cisco uBR7246 allow only known cable modems to send upstream data move cable modems to different channels and define a length of time a cable modem can request a connection To manage cable modems perform the following tasks Activate Cable Modem Authentication Activate Cable Modem Upstream Address Verification Activate Cable Modem Upstream Address Verification Activate Cable Modem Insertion Interval Note The defau
26. ler Activate the Upstream Ports Set the Upstream Frequency You need to set the upstream frequency of your RF output to comply with the expected input frequency of your Cisco MC11 cable modem You do this by entering a fixed frequency of the upstream RF carrier for an upstream port The valid range for a fixed upstream frequency is 5 000 000 Hz to 42 000 000 Hz Note Make sure that the upstream frequency selected does not interfere with the frequencies used for any other upstream applications running in the cable plant Note The cable interface will not operate until you either set a fixed upstream frequency or create and configure a spectrum group See the section Create Spectrum Groups later in this document To set the upstream frequency use the following command in cable interface configuration mode Command Purpose cable upstream port frequency up freq hz Enter the fixed center frequency for your upstream RF carrier in Hz VC 144 Voice Video and Home Applications Configuration Guide Set the Upstream Input Power Level Validation Tips To verify the current value of the upstream frequency enter the show controllers cable command for the upstream port that you have just configured router show controllers cable 6 0 u0 Cable6 0 Upstream 0 is up Frequency 7 008 MHz Channel Width 1 6 MHz QPSK Symbol Rate 1 280 Msps Nominal Input Power Level 0 dBmV Tx Timing Offset 0 Ranging Backoff Start 0 Ranging
27. lt values for the commands used in these configuration steps are in most cases adequate to configure the Cisco uBR7246 Activate Cable Modem Authentication You can activate authentication so all cable modems must return a known text string to register with the Cisco uBR7246 for access to the network The text string can be from to 80 characters in length The default is on cable modem authentication is activated Configuring Cisco UBR7246 Universal Broadband Router Features VC 157 Manage Cable Modems on the HFC Network Validation Tips To activate cable modem authentication use the following command from the cable interface configuration mode Command Purpose cable shared secret secret key Enable cable modem authentication To verify if cable modem authentication has been activated or deactivated enter the command more system running config and look for the cable interface configuration information If cable modem authentication has been activated it does not appear in this output If cable modem authentication has been deactivated it appears in this output as no cable secret shared as shown in this command output excerpt router more system running config Building configuration Current configuration l interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive no cable secret shared cable insertion interval 150000 cable downstream annex B cable downstream modulation 64qam cable d
28. n 64qam Set the standard MCNS rate To verify the downstream modulation setting enter the show controllers cable command for the downstream port that you have just configured router show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 Troubleshooting Tips If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure you have selected the default if you are not certain about the modulation rate needed Make sure the downstream carrier is active by entering the cable downstream if output command Set the Downstream Interleave Depth Validation Tips The next step is to set the interleave depth for a downstream port on a cable modem card A higher interleave depth provides more protection from bursts of noise on the HFC network however it will increase downstream latency The valid values are 8 16 32 default 64 and 128 To set the downstream interleave depth use the following command in cable interface configuration mode Command Purpose cable downstream interleave depth 8 16 32 64 128 Set the downstream interleave depth To verify the
29. n upstream channel the spectrum manager reassigns the upstream channel to a different upstream frequency Frequency agility is configured and activated using spectrum groups A spectrum group is a table of frequencies that can be used by upstream ports to implement a frequency hopping policy There are two types of policies blind and scheduled with two corresponding types of spectrum groups Blind The spectrum manager automatically assigns a new upstream channel frequency when station maintenance keep alive messages fail for approximately 2 5 minutes This represents a complete impairment of the upstream due to noise plant or equipment failure Scheduled The spectrum manager automatically assigns a new upstream frequency at set times during the day Configuring Cisco UBR7246 Universal Broadband Router Features VC 151 Configure and Activate Frequency Agility Note The cable interface will not operate until you either create and configure a spectrum group or set a fixed upstream frequency From the interface configuration prompt an interface is assigned membership in a spectrum group From the interface point of view the spectrum group also represents the set of upstreams connected to the same group of fiber nodes This allows the spectrum manager to know if upstream frequencies need to be managed together The configuration and activation of frequency agility depends on each cable operator s physical plant To con
30. nd when you entered the show interface cable command Activate Host to Host Communication Proxy ARP Proxy ARP allows the Cisco uBR7246 to issue ARP requests on behalf of cable modems on the same cable network subnet Note Because the downstream and upstreams are separate interfaces modems cannot directly perform ARP with other modems on the cable plant Note The default values for the commands used in this configuration task are in most cases adequate to configure the Cisco uBR7246 VC 154 Voice Video and Home Applications Configuration Guide Activate Proxy ARP Requests Activate Proxy ARP Requests Validation Tips To activate proxy ARP for host to host communications use the following command in cable interface configuration mode Command Purpose cable proxy arp Enable proxy ARP on the cable interface To verify if proxy ARP has been activated or deactivated enter the command more system running config and look for the cable interface configuration information If proxy ARP has been activated it does not appear in this output If proxy ARP has been deactivated it appears in the output as no cable proxy arp as shown in this command output excerpt router more system running config Building configuration Current configuration l interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive no cable proxy arp cable insertion interval 150000 cable downstream annex B cable dow
31. nstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure you entered the correct port and modem card slot number when you activated proxy ARP Set Optional IP Parameters There are additional IP parameters that you can optionally set to enable downstream echoing of upstream data To configure optional IP parameters perform the following tasks Activate IP Multicast Echo e Activate IP Broadcast Echo Note The default values for the commands used in these configuration steps are in most cases adequate to configure the Cisco uBR7246 Configuring Cisco UBR7246 Universal Broadband Router Features VC 155 Set Optional IP Parameters Activate IP Multicast Echo Validation Tips You can activate upstream IP multicast echo so that the Cisco uBR7246 can echo multicast packets The default is on IP multicast echo is activated To activate IP multicast echo use the following command in cable interface configuration mode Command Purpose cable ip multicast echo Enable IP multicast echo To verify if IP multicast echo has been activated or deactivated enter the command more system running config and look for the cable interface configuration information If IP multicast echo has been activa
32. on l interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive cable source verify cable insertion interval 2000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure that you entered the correct slot and port numbers when you entered cable interface configuration mode Activate Cable Modem Insertion Interval When a cable modem is ready to transmit data it requests a channel from the Cisco uBR7246 You can limit the amount of time that a cable modem requests a channel for the first time from the Cisco uBR7246 A cable modem s initial channel request is known as insertion The valid range is 100 to 2000 milliseconds To activate cable modem insertion interval use the following command in cable interface configuration mode Command Task cable insertion interval milliseconds Set the insertion interval in milliseconds Configuring Cisco UBR7246 Universal Broadband Router Features VC 159 Universal Broadband Features Configuration Example Validation Tips To verify that a cable modem insertion interval has been set enter the command more system running config and look for the cable interface configuration information as shown in this command output
33. ons Configuration Guide
34. ownstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure you entered the correct slot and port numbers when you entered cable interface configuration mode Activate Cable Modem Upstream Address Verification You activate cable modem upstream address verification to ensure that only known cable modems on the HFC network can transmit upstream data to a Cisco uBR7246 The default is off cable modem upstream address verification is deactivated To activate or deactivate cable modem upstream verification use the following command Command Purpose cable source verify Activate cable modem upstream verification VC 158 Voice Video and Home Applications Configuration Guide Activate Cable Modem Insertion Interval Validation Tips To verify that cable modem upstream verification has been activated or deactivated enter the command more system running config and look for the cable interface configuration information If cable modem upstream verification has been deactivated it does not appear in this output If cable modem upstream verification has been activated it appears in this output as cable source verify as shown in this command output excerpt router more system running config Building configuration Current configurati
35. r Currently this is always u0 Make sure you have selected a valid input power level for your headend and the cable modems on your HFC network Activate Upstream Forward Error Correction The Cisco uBR7246 uses forward error correction FEC to attempt to correct any upstream data that might have been corrupted FEC is activated by default and should not be disabled When FEC is activated all cable modems on the network also activate FEC VC 146 To activate the upstream forward error correction use the following command in cable interface configuration mode Command Purpose cable upstream port slot fec Enable FEC Voice Video and Home Applications Configuration Guide Activate the Upstream Scrambler Validation Tips Troubleshooting Tips To verify if FEC is activated or deactivated enter the command more system running config and look for the cable interface configuration information The following is an excerpt from the more system running config command output router more system running config Building configuration I interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive cable insertion interval 150000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown If you are having trouble
36. rivacy To encrypt upstream and downstream data you need to configure and activate baseline privacy Baseline privacy on an HFC network is configured with key encryption keys keks and traffic encryption keys teks The encryption is based on 40 bit or 56 bit data encryption standard DES encryption algorithms A kek is assigned to a cable modem based on the cable modem s service identifier SID and permits the cable modem to connect to the Cisco uBR7246 when baseline privacy is activated The tek is assigned to a cable modem when its kek has been established The tek is used to encrypt data traffic between the cable modem and the Cisco uBR7246 Keks and teks can be set to expire based on a grace time or a life time value A grace time key is used to assign a temporary key to a cable modem to access the network A life time key is used to assign a more permanent key to a cable modem Each cable modem that has a life time key assigned will request a new life time key from the Cisco uBR7246 before the current one expires Note This feature is not available in all Cisco IOS software versions in addition this is an export controlled feature Check to make sure that the Cisco IOS software you are using supports baseline privacy Configuring Cisco UBR7246 Universal Broadband Router Features VC 149 Configure and Activate Baseline Privacy The configuration and activation of baseline privacy depend on each cable operator s physical pl
37. show controllers cable 6 0 downstream Cable6 0 Downstream is up Frequency 96000000 Channel Width 6 MHz 64 QAM Symbol Rate 5 056941 Msps FEC ITU T J 83 Annex B R S Interleave I 32 J 4 Troubleshooting Tips If you are having trouble with this configuration Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Configuring Cisco UBR7246 Universal Broadband Router Features VC 143 Configure the Upstream Cable Interface Configure the Upstream Cable Interface The next step is to configure the upstream cable interface In this case upstream refers to the data flow from a cable modem to the Cisco MC11 modem card in a Cisco uBR7246 The user s cable modem sends an RF signal back to the MC11 cable modem card which translates the RF signal back to data format Upstream cable interface commands configure the frequency and input power level of the upstream signal in addition to error detection and correction of the upstream signal The configuration of the upstream cable interface depends on each cable operator s physical plant Perform the following tasks to configure the upstream cable interface Set the Upstream Frequency Set the Upstream Input Power Level Activate Upstream Forward Error Correction Activate the Upstream Scramb
38. stream PHY Downstream PHY unit The downstream PHY generates a modulated intermediate frequency IF output signal at a frequency of 44 MHz and passes the IF signal to an external IF to RF upconverter installed in the downstream path Upstream PHY unit The upstream PHY receives the modulated upstream signal at a frequency of 5 MHz to 40 MHz and passes the signal to the cable MAC to remove the framing and encryption formats Spectrum manager The spectrum manager continuously monitors the noise in unused upstream channels If the signal to noise ratio reaches an unacceptable level on a particular channel the spectrum manager will automatically assign a new upstream channel to the cable modem using that channel This feature is referred to as frequency agility You must install at least one Cisco MC11 cable modem card in the Cisco uBR7246 chassis to establish communication between the Cisco uBR7246 and the HFC network Figure 38 shows the network topology for the modem card and illustrates network connections using the Cisco uBR7246 Configuring Cisco UBR7246 Universal Broadband Router Features VC 133 Figure 38 Topology for UBR7246 Universal Broadband WAN Internet ATM 100BT 10BT cas 7 4a 100BT Sj a 100BT ISR Proxy server Cisco uBR7246 IF 1 US RF MSO Multiple Service Organization Analog TV 5 42 MH 1 signals Z Upconverter Lad DS RF 54 860 Mhz l i i i l l l I 1 Combiner
39. ted it does not appear in this output If IP multicast echo has been deactivated it appears in this output as no cable ip multicast echo as shown in the command output excerpt below router more system running config Building configuration Current configuration I interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive no cable ip multicast echo cable insertion interval 150000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown Troubleshooting Tips If you are having trouble make sure that you have entered the correct slot and port numbers when you entered cable interface configuration mode Activate IP Broadcast Echo You can activate upstream IP broadcast echo so that the Cisco uBR7246 can echo broadcast packets The default value is off IP broadcast echo is not activated To activate IP broadcast echo use the following command in cable interface configuration mode Command Purpose cable ip broadcast echo Enable IP broadcast echo VC 156 Voice Video and Home Applications Configuration Guide Manage Cable Modems on the HFC Network Validation Tips To verify if IP broadcast echo has been activated or deactivated enter the command more system running config and look for the cable interface conf
40. tion Guide Activate Baseline Privacy Validation Tips To verify the tek life time or grace time values that have been set enter the show cable privacy tek command router show cable privacy tek Configured TEK life time value 56000 Troubleshooting Tips If you are having trouble make sure you have entered a valid value for grace time or life time Activate Baseline Privacy After the kek and tek values have been set you can activate encryption on the HFC network To activate baseline data privacy on the HFC network use the following commands in global configuration mode Step Command Purpose 1 cable privacy enable Activate cable privacy This is the default 2 cable privacy mandatory Activate cable privacy and do not allow access for any unencrypted cable modem connections Validation Tips To verify if baseline privacy is activated enter the cable privacy enable or cable privacy mandatory command By default cable privacy is enabled and can only be disabled with the no cable privacy command Troubleshooting Tips If you are having trouble make sure you have entered a valid value for grace time or life time for kek and tek privacy Configure and Activate Frequency Agility Frequency agility is a way to improve performance on upstream signal traffic and to compensate for noise and interference The spectrum manager monitors the upstream frequencies if too much noise or interference is detected in a
41. urrent configuration I interface Cable6 0 ip address 1 1 1 1 255 255 255 0 no keepalive cable insertion interval 150000 cable downstream annex B cable downstream modulation 64qam cable downstream interleave depth 32 cable downstream symbol rate 5056941 cable upstream 0 frequency 15008000 cable upstream 0 fec cable upstream 0 scrambler no cable upstream 0 shutdown i end If you are having trouble Make sure the cable connections are not loose or disconnected Make sure the cable modem card is firmly seated in its Cisco uBR7246 chassis slot Make sure that you have entered the correct slot and port numbers when you typed the command Make sure that you have entered the correct upstream port number Currently this is always u0 Activate the Upstream Ports Activate the RF carrier on the upstream ports Each upstream port must be activated to enable upstream data from the cable modems on the HFC network to the Cisco uBR7246 VC 148 To activate the upstream ports use the following commands in global configuration mode Step Command Purpose 1 interface cable port slot Specify a cable interface and enter the cable interface configuration mode no cable upstream 0 shutdown Enable upstream data traffic Voice Video and Home Applications Configuration Guide Configure and Activate Baseline Privacy Validation Tips To verify if the upstream ports are activated or deactivated ent
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