Chapter 8 – Troubleshooting Converged Networks Objectives
Contents
1. E Chapter 8 Troubleshooting Converged Networks Objectives Explain the operation of the Cisco Centralised Wireless model e Describe LWAPP operation amp troubleshooting techniques gt Explain the requirement for QoS converged networks Describe basic QoS operation amp troubleshooting techniques Describe basic multicast operation amp troubleshooting techniques Chapter 8 Autonomous or Ligh tweigh t BIRMINGHAM e Most Cisco wireless access points bridges are available as autonomous or lightweight devices Lightweight APs LWAP use Lightweight Access Point Protoco LWAPP and must have a Wireless LAN Controller WLC to function within the network Standalone Solution e Most Cisco autonomous APs can be software upgraded to function as Split MAC or Lightweight Solution LWAPP Control Lightweight Messages Gisco Wireless Access Point LAN Controller LWAPP Data anne To and from Encapsulation switched routed wired network Campus 802 10 trunk Infrastructure Chapter 8 E Cisco Unified Wireless Network ERS Academy City University Unified Advanced Services Unified cellular and Wi Fi VoIP Advanced threat detection identity networking location based security asset tracking and guest access World Class Network Management Same level of security scalability reliability ease of deployment and management for wireless LANs as wired2. Ri config cmap exit Ri config class map match any c ass2 Ri config cmap match access group 102 R1 config cmap exit Ri config class map match any noip R1 config cmap match not protocol ip R1 config cmap exit Chapter 8 Step 2 Creatina Policy Maps BIRMINGHAM City University 256kbps Data Stream 50 0 Kat Nested Policy config policy map policy R1 config pmap class classi Ri contig policy map 1 Ri config pmap c bandwidth 100 RL con a bee cyt bandwidth 50 Ri config pmap c queue limit 30 Ri config pmap c class2 R1 config pmap exit Ri config pmap c bandwidth 40 Ri config pmap class class2 R1 config policy map 2 Ri config pmap c bandwidth 80 Ri config pmap class class Ri config pmap exit default Ri config pmap c shape average 128000 Ri config pmap c service policy 1 Chapter 8 Step 3 Apply Service Polic 256kbps Data Stream 50 0 Ri config interface s0 0 Ri config if service policy output policy R1 config if exit BIRMINGHAM City University Although you can assign the same traffic policy to multiple interfaces each interface can have only one traffic policy attached at the input and only one traffic policy attached at the output Chapter 8 Basic Verification Commands BIRMINGHAM R1 show class map Class Map match any class default id O Match any Class Map match all MUSIC id 2 R1 show policy map Match protocol kazaa Policy Map
3. TSHOOT EXAMPLE _ Class EMAIL Class Map match any EMAIL id 1 Bandwidth 128 kbps Max Threshold 64 Match protocol pop3 packets Match protocol imap Match protocol smtp Class MUSIC police cir 32000 bc 1500 Class Map match all VOICE id 3 conform action transmit Match protocol rtp audio exceed action drop Class VOICE Strict Priority Bandwidth 256 kbps Burst 6400 Bytes Chapter 8 Basic Verification Commands R1 show policy map interface serialO 1 SerialO 1 Service policy output TSHOOT EXAMPLE Class map EMAIL match any O packets O bytes 5 minute offered rate O bps drop rate O bps Match protocol pops O packets O bytes D minute rate O bps Match protocol imap O packets O bytes D minute rate O bps Match protocol smtp O packets O bytes D minute rate O bps Queueing Output Queue Conversation 265 Bandwidth 128 kbps Max Threshold 64 packets pkts matched bytes matched 0 0 depth total drops no buffer drops 0 0 0 BIRMINGHAM Ci gt Chapter 8 dech Unified Communications Design Networking BIRMINGHAM Considerations Video an Voice Video weier AN Mail Resources Call Agent E IP Phones Le 2 ie if EI Deen IP WAN al ER Endpoints WEE SE Gateway d me Bu a GK Voice Video 1 H 323 SIP Room W Gatekeeper Gateway system Voice Video Legacy H 320 Conference Resources Systems Like voice traffic video traffic is l
4. group Timers Uptime Expires Interface state Interface Next Hop or VCD State Mode 224 0 100 4 02 37 12 RP is 192 168 47 14 flags S Incoming interface SerialO RPF neighbor 10 4 53 4 Outgoing interface list Ethernet1 Forward Sparse 02 37 12 0 03 42 Ethernet2 Forward Sparse 02 52 12 0 01 23 192 168 46 0 24 224 0 100 4 02 37 12 flags RT Incoming interface Ethernet1 RPF neighbor 10 4 53 4 Outgoing interface list Ethernet2 Forward Sparse 02 44 21 0 01 47 Chapter 8 E Chapter 8 Troubleshooting Converged Networks Objectives Explain the operation of the Cisco Centralised Wireless model e Describe LWAPP operation amp troubleshooting techniques gt Explain the requirement for QoS converged networks Describe basic QoS operation amp troubleshooting techniques Describe basic multicast operation amp troubleshooting techniques Chapter 8 ol CISCO Any Questions Chapter 8
5. in a single stream Host a Downstream routers Router perform packet multiplication over Access control and threat management mechanisms need to receiving links when consider the various protocols and traffic flows that result necessary from a video enabled network e g SIP H 323 SCCP Skinny RTP RTCP Chapter 8 IP Multicast Address Structure Wa IP group addresses Class D address high order three bits are set Range from 224 0 0 0 through 239 255 255 255 28 bits Class D ctlilalo Multicast Group ID Local scope addresses 224 0 0 0 to 224 0 0 255 Global scope addresses 224 0 1 0 to 238 255 255 255 Administratively scoped addresses 239 0 0 0 to 239 255 255 255 Chapter 8 BIRMINGHAM City University IANA Ethernet MAC Address Range Normally network interface cards NICs on a LAN segment only receive packets destined for their burned in MAC address However there is no Address Resolution Protoco ARP equivalent for multicast address mapping IANA has set aside the vendor code portion of the reserved Organizationally Unique Identifier OUT value to identify multicast MAC addresses gt Multicast MAC addresses always begin with the low order bit 0x01 in the first octet Specifically the Ox01005e prefix plus the next lower bit which is zero has been reserved for mapping Layer 3 IP multicast addresses into Layer 2 MAC addresses The complete multicast MAC address range is from
6. int 90 37 GigabitEthernetO 34 trust state not trusted trust mode not trusted trust enabled flag ena COS override dis BIRMINGHAM Ci gt VLANs 10 A trust boundary is the point within the network where QoS markings such as DSCP are first accepted default COS O By default switch ports will reset DSCP Mutation Map Default bach DSCP values unless you explicitly tell Mutation Map the port to trust those values Trust device None qos mode port based Chapter 8 WLAN Troubleshooting Example 2 GI we aon Gio 36 VLANs 10 amp 20 BIRMINGHAM City University 9 SS lt VLANs 10 SWi config int 90 34 SW1 show mls gos int g0 34 SWi config if mis gos trust dscp GigabitEthernet0O 34 SWi config if end trust state trust dscp SW1 end trust mode trust dscp SW1 trust enabled flag ena COS override dis default COS O DSCP Mutation Map Default DSCP Mutation Map Trust device None qos mode port based Chapter 8 dch Converged Network Realities Networking Academy BIRMINGHAM City University Remote Traditional data traffic Seel 2 Ze characteristics Backbone Gu gt z 3 lt Campus Bursty data flow Backbone sty 45 Se FIFO access Not overly time sensitive delays OK Brief outages are Training Other survivable Mo 8 Converged network realities Campus Constant small packet voice Compus Backbone f flow competes w
7. perceived as wireless problems result from underlying issues on the wired network PoE WAPS are often installed away from power outlets and require Power over Ethernet PoE to provide a 48vdc supply over their data connection VLANs wireless users might experience connectivity issues if traffic from their wireless VLAN is not permitted over a trunk in the wired network Security UDP ports 12222 and 12223 are used by LWAPP and should be permitted between a WAP and a WLC DHCP WLANs rely on DHCP to provide roaming clients with IP addresses QoS Latency sensitive traffic traveling over a wireless network might suffer from poor performance if QoS markings are not preserved as traffic crosses the boundary between the wireless and wired portions of a network Chapter 8 WLAN Troubleshooting Example 1 GI we aon Gio 36 VLANs 10 amp 20 Networking Academy BIRMINGHAM City University VLANs 10 Ne Wireless services have suddenly stopped clients are not able to associate to the AP Even from the wired PCs that are used for troubleshooting it is not possible to connect to the AP or the WLC using either SSH or HTTPS SW1 show cdp neighbors Capability Codes R Router T Trans Bridge B Source Route Bridge S Switch H Host I IGMP r Repeater P Phone Device ID Local Intrfce Holdtme Capability Platform Port ID ap Gig 0 37 128 TI AIR LAP125 GigO 521 8 Gig 0 39 135 AIR LAP521 Fa
8. 0100 5e00 0000 through 0100 5e7f ffff Fixed Variable A E 00000001 00000000 01011110 00000000 00000000 00000000 00000001 00000000 01011110 01111111 1111111 11111111 Chapter 8 IP Multicast to MAC Multicast Mapping The translation between IP multicast and MAC address is achieved by the mapping of the low order 23 bits of the IP Layer 3 multicast address into the low order 23 bits of the IEEE Layer 2 MAC address BIRMINGHAM Ci gt 224 239 x y z IP Multicast 224 1 0 1 P Multicast 441 00 0 0 0 0 0 0 0 0 0 01 o 0 00 00 0 0 0 0 0 0 0 0 0 1 5 Bits 23 Bits Transferred Unused to MAC Address Multicast EELER EE First 25 bits fixed by Last 23 bits of IP Multicast IANA requirements address map to last 23 bits of MAC address 0100 5e01 0001 Chapter 8 BIRMINGHAM Ci gt IANA Ethernet MAC Address Range This gives the possibility that 32 different multicast IP addresses could all correspond to a single multicast MAC address 11100000 00000001 00000000 00000001 224 1 0 1 11101111 00000001 00000000 00000001 239 1 0 1 11100000 10000001 00000000 00000001 224 129 0 1 11101111 10000001 00000000 00000001 239 129 0 1 Chapter 8 How are Multicast Addresses SE Assigned Static Global Group Address Assignment Temporary method to meet immediate needs Group range 233 0 0 0 233 255 255 255 Your AS number is inserted in middle two octets Remaining low order octet used for g
9. LANs Network Unification Integration into all major switching and routing platforms Secure innovative WLAN controllers Mobility Platform Ubiquitous network access in all environments a TE a a ae wood Sg Zem Enhanced productivity Proven platform with large g ei install base and 63 market share Plug and Play Client Devices 90 of Wi Fi silicon is Cisco Compatible Certified Out of the Box wireless security Chapter 8 Switched Routed Wired Network LWAPP Tunnel Se ul The control traffic between the access point and the controller is encapsulated by Lightweight Access Point Protocol LWAPP and encrypted via the Advanced Encryption Standard AES The data traffic between the access point and controller is also encapsulated with LWAPP but not encrypted Chapter 8 Wireless LAN Controller Interfaces ua 10 WLAN Default Gateway 192 168 10 1 BIRMINGHAM Ci gt ML AN 100 VLAN Default Gateway 192 168 100 1 Trunk VLAN 10 100 Distribution Port PA Management Interface 192 168 10 10 000000 e AP management Interface 192 168 10 11 Virtual 1 1 1 1 q Dynamic Interface 192 168 100 2 l VLAN 100 LWAPP Tunnel VLAN 100 JX VLAN 100 7 7 Ki I I wem ef Bn wem ef d be h AP1 AP2 192 168 10 12 192 168 10 13 Chapter 8 Wired Network Issues Impacting on WLANs GN Many issues that might be
10. atency sensitive Therefore many of the same design and troubleshooting considerations for voice traffic for example QoS considerations also apply to video traffic Chapter 8 Unified Communications Design Considerations Video BIRMINGHAM City University e Due to the bandwidth intensive and latency sensitive nature of video consider the following when designing or troubleshooting a video network e QoS Like voice video packets need to be allocated an appropriate amount of bandwidth and be treated with high priority e Availability Also like voice video networks should be built on an underlying data network with reliable components and redundancy e Security Appropriate security measures such as encryption and authentication should be in place in a video network e Multicasting Multicasting allows a multicast server to send traffic for example a video stream to a destination Class D IP address known as a multicast group Chapter 8 E Unicast vs Multicast Networking BIRMINGHAM Unicast City University Academy OO _ Gender has to send the Sc same data flow to each Sender receiver separately Host gt gt lt The sender has to make NX Copies of the same Motion packet and send them once for each receiver Multicast Data packets are sent to multiple receivers the ff ns packets are not gt L 7 z duplicated for every Sender receiver but are sent
11. config if ip pim dense mode Source 1 Group 224 1 1 1 Rendezvous or Point RP RD contig if A ip pim sparse mode ES _ CB F20 0 Sw RD config if ip pim sparse dense eem gel SET TT DEER e w Ae em ST wem 7 f 192 168 1 50 mode ES ES RC config ip multicast routing RC config interface fa0 0 RC config if ip pim sparse dense mode RC config if exit RC config ip pim rp address 192 168 1 50 192 168 0 0 0 0 255 255 Chapter 8 Verify PIM Neighbours BIRMINGHAM R1 show ip pim interface Address Interface Ver Nbr Query DR DR Mode Count Intvl Prior 10 139 16 133 Serial0O 0 v2 S 1 30 1 0 0 0 0 10 127 0 170 Serial1 2 v2 S 1 30 1 0 0 0 0 10 127 0 242 Serial1 3 v2 S 1 30 1 0 0 0 0 R1 fshow ip pim neighbor PIM Neighbor Table Neighbor Interface Uptime Expires Ver DR Address Priority 10 139 16 134 SerialO O 00 01 46 00 01 28 v2 1 10 127 0 169 Serial1 2 00 01 05 00 01 40 v2 1 10 127 0 241 Serial1 3 00 01 56 00 01 18 v2 1 Chapter 8 KH Verify PIM Routing LS R1 show ip mroute City University IP Multicast Routing Table Flags D Dense S Sparse B Bidir Group s SSM Group C Connected L Local P Pruned R RP bit set F Register flag T SPT bit set J Join SPT M MSDP created entry X Proxy Join Timer Running A Candidate for MSDP Advertisement U mm I Received Source Specific Host Report Z Multicast Tunnel Joined MDT data group y Sending to MDT data
12. ent CNRC mr Sources initially send their multicast packets to the RP which in turn forwards data through a shared tree to the members of the group eres 1 enee 2 Notation G Notation G Notation G Se Sa S Source G 224111 G 224222 G Group Chapter 8 Auto RP Auto RP is a Cisco proprietary method of automatically selecting an RP Auto RP identifies a centrally located router to act as a mapping agent The mapping agent learns of all candidate RPs on 224 0 1 39 all PIM routers automatically join this group The mapping agent advertises all candidate RPs on 224 0 1 40 Chapter 8 Protocol Independent Multicast PIM GE e PIM maintains the current IP multicast service mode of receiver initiated membership PIM is not dependent on a specific unicast routing protocol e With PIM routers maintain forwarding tables to forward multicast datagrams PIM can operate in dense mode or sparse mode Dense mode protocols flood multicast traffic to all parts of the network and prune the flows where there are no receivers using a periodic flood and prune mechanism Sparse mode protocols use an explicit join mechanism where distribution trees are built on demand by explicit tree join messages sent by routers that have directly connected receivers Chapter 8 BIRMINGHAM Ci gt PIM Configuration RD config ip multicast routing RD config interface fa0 0 RD
13. ery interval is 60 seconds IGMP querier timeout is 120 seconds IGMP max query response time is 10 seconds Last member query count is 2 Last member query response interval is 1000 ms Inbound IGMP access group is not set IGMP activity 1 joins O leaves Multicast routing is enabled on interface Multicast TTL threshold is O IGMP querying router is 0 0 0 0 this system Multicast groups joined by this system number of users 224 0 1 40 1 Chapter 8 Multicast Routing Protocols Source Distribution Tree BIRMINGHAM City University Source 2 IP 10 2 0 1 t Group 224 2 2 2 With a source tree a separate tree is built for each source to all members of its group Source 1 EM IP 101 01 Group 224 1 1 1 Le Because the source tree takes the shortest path from the Source to its receivers it is also called a shortest path tree SPT pam R Receiver 1 reine 2 Notation 5 6 S Source Notation tS et S G S 1010 1 10 2 0 G Group G 224111 eee Chapter 8 Multicast Routing Protocols Shared Tree BIRMINGHAM Ci gt Source 1 Source 2 em gt 10 1 0 1 E 1P 10 2 0 1 Group 224 1 1 1 Se Group 224 2 2 2 C i Shared tree protocols create multicast forwarding paths that eg rely on a central core router that serves as a rendezvous point RP between multicast Sources and destinations ES Mapping Ag
14. itchport access vlan 10 e The link mode between the IP phone and the switch is negotiated the switch instructs the phone to use a specia case 802 1Q trunk or a single VLAN access link With a trunk the voice traffic can be so ated from other user data providing security and QoS capabilities eTo configure the IP phone uplink configure the switch port where it connects The switch port does not need any special trunking configuration commands if a trunk is wanted eIf an 802 1Q trunk is needed a special case trunk is automatically negotiated by DTP and COP BIRMINGHAM City University Chapter 8 Modular CoS CLI Componen S BIRMINGHAM Define Overall QoS Policy 1 2 Class Map Policy Map Apply a service Define classes Define QoS policies olic of traffic for classes paS A What traffic do What will be done ia we care about to this traffic implemented Each class of traffic Defines a policy map is defined using a which configures the denier class map QoS features associated Poe 9 with a policy map with a traffic class to an interface previously identified using a class map Chapter 8 Step 1 Creating Class Maps BIRMINGHAM City University 256kbps Data Stream 50 0 Ri config access list 101 permit tcp any any eq 22 Ri config access list 102 permit tcp any any eq 80 Ri config class map match any c ass1 Ri config cmap match access group 101
15. ith bursty data flow Critical traffic must have priority Voice and video are time sensitive Brief outages are not acceptable Chapter 8 dech Unified Communications Design BIRMINGHAM City Uni gt Considerations Voice Ee The following list summarizes the design considerations of integrating unified communications into a campus Quality of Service Bandwidth delay jitter packet loss Network QoS Readiness Trust Boundaries Switch QoS e High Availability STP RSTP HSRP GLBP VRRP Security Traffic Segregation Voice versus Data VLANs Firewalling Filtering Provisioning and Management PoE DHCP TFTP NTP CDP Trunking VLANs Chapter 8 IP Phone Initialisation BIRMINGHAM IP phone connected Switch detects IP phone amp applies power EE CDP transaction between phone A switch mmm IP phone placed in proper VLAN DHCP process assigns IP configuration m IP phone requests config file via TFTP a iere Server IP phone registers with call manager E EEE eIf the services that the network infrastructure needs to provide are not available are mis configured or are simply not reachable IP phones might not be able to operate Chapter 8 IP Phone VLAN Considerations 802 1q SL a iii Se Fa0 11 _ VE Fee Voice VLAN Data VLAN 10 110 SWi config int fa0 11 SWi config if switchport mode access SW1 config if switchport voice vlan 110 SWi config if sw
16. roup assignment e Defined in RFC 2770 GLOP Addressing in 233 8 Manual address allocation by the admin is still the most common practice Chapter 8 Multicast Protocols BIRMINGHAM Host Sender De Host Host PIM gt Router Host IGMP There are two main protocols involved in a multicast enabled Routers will run a multicast routing protocol typically Protocol Independent Multicast PIM whose main role is to advertise the location of multicast receivers The second main component is the way hosts subscribe to groups and announce themselves as members of the group which is typically done using Internet Group Management Protocol IGMP Chapter 8 Internet Group Management Protocol IGMP How hosts tell routers about group membership Routers solicit group membership from directly connected hosts RFC 1112 specifies IGMPv1 Supported on Windows 95 RFC 2236 specifies IGMPv2 Supported on latest service pack for Windows and most UNIX systems RFC 3376 specifies IGMPv3 Supported in Window XP and various UNIX systems Chapter 8 KH IGMPv2 Operation Academy Report City University Lo Members joining a multicast group do not 11111 11112 have to wait for a query to join They send an unsolicited report indicating their interest RA hears the leave message and sends a group specific guery to see if any other group members are present H3 has no
17. s O 521 7 Gig 0 34 122 AIR LAP521 Fos O Cisco_9a 8c e0 Gig 0 36 175 H AIR WLC210 Unit O Slot O Port 1 Chapter 8 WLAN Troubleshooting Example 1 GI we aon Gio 36 VLANs SW1 show interface status BIRMINGHAM Ci gt VLANs 10 Port Name Status vlan Duplex Speed Type Gi0 1 notconnect 1 auto auto 10 100 1000Base TX Gi0 2 notconnect 1 auto auto 10 100 1000Base TX output omitted for brevity Gi0 34 connected 1 a full a 100 10 100 1000BaseTX Gi0 35 notconnect 1 auto auto 10 100 1000Base TX Gi0 36 connected trunk a full a 100 10 100 1000BaseTX Gi0 37 connected 10 a full a 1000 10 100 1000BaseTX Chapter 8 WLAN Troubleshooting Example 1 GI we aon Gio 36 VLANs Networking Academy BIRMINGHAM Ci gt VLANs 10 N EA Re SW 1 show interfaces switchport begin 0 36 Name Gi0 36 Switchport Enabled Administrative Mode trunk Operational Mode trunk Administrative Trunking Encapsulation dotiq Operational Trunking Encapsulation dotiq Negotiation of Trunking On output omitted for brevity Trunking VLANs Enabled 1 SW1 config int 90 36 SW1 config if switchport trunk allowed vlan add 10 20 SWIi config if end Chapter 8 WLAN Troubleshooting Example 2 yA VLANs me ea VLANs Gi0 36 BR 10 amp 20 X ET O00000 Wireless services are now available but wireless users are still experiencing performance issues especially with VoIP traffic SW1 show mls gos
18. t left the multicast group 224 1 1 1 yet so it responds with a report message 224 1 1 1 224 1 1 1 rtr a gt show ip igmp group IGMP Connected Group Membership Group Address Interface Uptime Expires Last Reporter 224 1 1 1 Ethernet Odlh3m 00 02 31 1 1 1 11 Query 204111 rtr a gt show ip igmp group IGMP Connected Group Membership Group 224 1 1 1 Group Address Interface Uptime Last Reporter 224 1 1 1 Ethernet Odlh3m 1 1 1 12 When H3 leaves RA again queries the group Because host H3 was the last ztr a gt ahow ip Zeg group remaining member of the multicast group conne EE nee 224 1 1 1 no IGMP membership report for group 224 1 1 1 is received and the group times out Chapter 8 IGMP Snooping BIRMINGHAM City University Switches become IGMP aware eIGMP packets are intercepted by the CPU or by special hardware ASICs IGMP Switch examines contents of IGMP Join messages to learn which ports want Sp what traffic WI 0100 5e01 0101 Must process all Layer 2 multicast packets Group 224 1 1 1 ES eAdministration load increased with multicast traffic load 0100 5e01 0101 bk S1 config ip igmp snooping S1 config ip igmp snooping vlan 10 Chapter 8 Verify Group State GE R1 show ip igmp interface Serial0 0 0 is up line protocol is up Internet address is 10 23 23 2 24 IGMP is enabled on interface Current IGMP host version is 2 Current IGMP router version is 2 IGMP qu
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