14 module
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The document discusses Frame Relay networking concepts and configuration. It describes how Frame Relay uses virtual circuits to connect devices and map network addresses to Data Link Connection Identifiers (DLCIs). It also covers configuring Frame Relay point-to-point subinterfaces on Cisco routers to establish connections between sites and resolve routing issues in non-broadcast multi-access (NBMA) environments.
14 module
- 1. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Establishing a Frame Relay PVC Connection Chapter 14
- 2. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Objectives Determine how Frame Relay operates Configure Frame Relay Configure Frame Relay subinterfaces Verify Frame Relay operation Upon completion of this chapter, you will be able to perform the following tasks:
- 3. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Overview Virtual circuits make connections Connection-oriented service DTE or CPE router Frame Relay works here. DCE or Frame Relay Switch CSU/DSU
- 4. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Stacks OSI Reference Model Application Presentation Session Transport Network Data Link Physical Frame Relay IP/IPX/Apple Talk, etc Frame Relay EIA/TIA-232, EIA/TIA-449, V.35, X.21, EIA/TIA-530
- 5. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Terminology Local Access Loop=T1 DLCI=400 DLCI=500 LMI 500=Active 400=Active Local Access Loop=64 kbps Local Access Loop=64 kbps
- 6. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Address Mapping Get locally significant DLCIs from provider Map your network addresses to DLCIs Frame Relay map 10.1.1.1 DLCI:500 PVC Inverse ARP or IP (10.1.1.1) Frame Relay DLCI (500) CSU/DSU
- 7. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 10.1.1.1 DLCI:500 PVC Frame Relay Signaling PVC DLCI:400 Keepalive Cisco supports three LMI standards: Cisco ANSI T1.617 Annex D ITU-T Q.933 Annex A LMI 500=Active 400=Inactive CSU/DSU
- 8. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Operation Frame Relay Cloud DLCI=100 DLCI=400 2
- 9. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 172.168.5.5 172.168.5.7 Frame Relay Inverse ARP and LMI Operation 3 Status Inquiry 3 Status Inquiry Frame Relay Cloud 2 DLCI=100 DLCI=400
- 10. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 4 DLCI 400=Active 4 DLCI 100=Active 3 Status Inquiry Status Inquiry Frame Relay Cloud DLCI=100 DLCI=400 172.168.5.5 172.168.5.7 Frame Relay Inverse ARP and LMI Operation 3 2
- 11. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Inverse ARP and LMI Operation 4 DLCI 400=Active 4 DLCI 100=Active 3 Status Inquiry Status Inquiry Frame Relay Cloud DLCI=100 DLCI=400 172.168.5.5 172.168.5.7 3 2 5 Hello, I am 172.168.5.5 on DLCI 100, who are you?
- 12. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Frame Relay Map 172.168.5.5 DLCI 400 Active Frame Relay Cloud DLCI=100 DLCI=400 Frame Relay Inverse ARP and LMI Operation (cont.) 172.168.5.5 172.168.5.7 6
- 13. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Hello, I am 172.168.5.7 on DLCI 400. Frame Relay Map 172.168.5.5 DLCI 400 Active Frame Relay Cloud DLCI=100 DLCI=400 Frame Relay Map 172.168.5.7 DLCI 100 Active 172.168.5.7 172.168.5.5 Frame Relay Inverse ARP and LMI Operation (cont.) 5 6 6
- 14. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Hello, I am 172.168.5.5 on DLCI 100. Hello, I am 172.168.5.7 on DLCI 400. Frame Relay Map 172.168.5.5 DLCI 400 Active Frame Relay Cloud DLCI=100 DLCI=400 Frame Relay Map 172.168.5.7 DLCI 100 Active 172.168.5.7 172.168.5.5 Frame Relay Inverse ARP and LMI Operation (cont.) 7 5 6 6
- 15. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Keepalive Keepalive Frame Relay Inverse ARP and LMI Operation (cont.) Hello, I am 172.168.5.5 on DLCI 100. Hello, I am 172.168.5.7 on DLCI 400. Frame Relay Map 172.168.5.5 DLCI 400 Active Frame Relay Cloud DLCI=100 DLCI=400 Frame Relay Map 172.168.5.7 DLCI 100 Active 172.168.5.7 172.168.5.5 8 8 7 5 6 6
- 16. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Configuring Basic Frame Relay HQ Branch Rel. 11.2 Router Rel. 10.3 Router interface Serial1 ip address 10.16.0.1 255.255.255.0 encapsulation frame-relay bandwidth 64 interface Serial1 ip address 10.16.0.2 255.255.255.0 encapsulation frame-relay bandwidth 64 frame-relay lmi-type ansi
- 17. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Configuring Basic Frame Relay (cont.) HQ Branch Rel. 11.2 Router Rel. 10.3 Router Inverse ARP is enabled by default does not appear in configuration output. interface Serial1 ip address 10.16.0.1 255.255.255.0 encapsulation frame-relay bandwidth 64 interface Serial1 ip address 10.16.0.2 255.255.255.0 encapsulation frame-relay bandwidth 64 frame-relay lmi-type ansi
- 18. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Selecting a Frame Relay Topology Star (Hub and Spoke) Full Mesh Partial Mesh
- 19. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Broadcast traffic must be replicated for each active connection Reachability Issues with Routing Updates A Circuit #21 Circuit #22 Circuit #23 D C B Problem: Routing Update B C D 2 3 1
- 20. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Resolving Reachability Issues Split horizon can cause problems in NBMA environments A single physical interface simulates multiple logical interfaces Subinterfaces can resolve split horizon issues S0 Physical Interface Logical Interface Subnet A Subnet B Subnet C S0.1 S0.2 S0.3
- 21. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Configuring Subinterfaces Multipoint Subinterfaces act as default NBMA network Can save subnets because uses single subnet Good for full-mesh topology Point-to-Point Subinterfaces act as leased line Each point-to-point connection requires its own subnet Good for star or partial-mesh topologies
- 22. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Configuring Subinterfaces (cont.) RTR1 s0.2-DLCI=110 s0.3-DLCI=120 s0.1 s0.2 s0.1 s0.3 <Output Omitted> interface Serial0 no ip address encapsulation frame-relay ! interface Serial0.2 point-to-point ip address 10.17.0.1 255.255.255.0 bandwidth 64 frame-relay interface-dlci 110 ! interface Serial0.3 point-to-point ip address 10.18.0.1 255.255.255.0 bandwidth 64 frame-relay interface-dlci 120 ! router rip network 10.0.0.0 <output omitted> RTR3 RTR2
- 23. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Multipoint Subinterfaces Configuration Example RTR1 RTR3 RTR2 RTR4 s2.1=10.17.0.2/24 s2.2=10.17.0.1/24 s2.1=10.17.0.4/24 s2.1=10.17.0.3/24
- 24. 2 Copyright © 1998, Cisco Systems, Inc. ICRC_revision_11.3 Multipoint Subinterfaces Configuration Example <Output Omitted> ! interface Serial2 no ip address encapsulation frame-relay ! interface Serial2.2 multipoint ip address 10.17.0.1 255.255.255.0 bandwidth 64 frame-relay map ip 10.17.0.2 120 broadcast frame-relay map ip 10.17.0.3 130 broadcast frame-relay map ip 10.17.0.4 140 broadcast ! router rip network 10.0.0.0 <Output Omitted>