Title: DECbrouter90 example of OSPF inter-area over Frame Relay subinterfaces Product: DECbrouter90 V10.x Question: How should the DECbrouter90 be configured to support OSPF over Frame-Relay subinterfaces? Solution: This is an example of how to configure IP OSPF Inter-Area routing across a Frame-Relay cloud between two DBR90's. In this example the FR circuit is treated as a WAN circuit by using subinterfaces. Using point-to-point subinterfaces is the reccomended method of running OSPF on a Frame-Relay networks (per rfc 1586), as it allows for partial-mesh topologies. ------------------ | | | Frame-Relay | | cloud | | ----------- | | | | | | | | | ------------------ DCE | | DCE DLCI #101 | | DLCI #100 | | / \ / \ / OSPF \ 17.1.1.251 / AREA #0 \ 17.1.1.252 DTE / \ DTE --------- --------- | S0 | | S0 | | BRUTK | | BRUTL | | E0 | | E0 | --------- --------- 16.1.1.251 | | 18.1.1.252 OSPF AREA #2 | | OSPF AREA #1 ------------------------- --------- ******************************************************************************** EXAMPLE DBR90 BRUTL CONFIGURATION ******************************************************************************** BRUTK#show config ! version 10.0 ! ! This is the version of the DECbrouter 90 code I used. ! interface Ethernet0 ! ip address 16.1.1.251 255.255.255.0 ! ! This IP address enables OSPF routing on this interface. ! interface Serial0 ! encapsulation frame-relay ! ! This command enables Frame Relay encapsulation running CHDLC. ! frame-relay lmi-type ansi ! ! This command sets up the LMI type whether it be CISCO, ANSI or CCITT. You ! need to ask your frame relay service provide what this should be configured ! for. ! keepalive 15 ! ! This is needed for LMI heart beat signals. ! interface Serial0.1 point-to-point ! ! This command configures a subinterface and allows the DBR90 to treat FR as a ! WAN circuit instead of a LAN. ! ip address 17.1.1.251 255.255.255.0 ! ! This IP address enables OSPF routing on this subinterface. ! frame-relay interface-dlci 101 ! ! There is NO requirement to map to the remote IP address (17.1.1.252) because ! this subinterface is treated as a WAN circuit. So we just need to map to the ! DLCI. 101 is the DLCI going to the remote router. ! router ospf 42 ! ! This command enables OSPF routing on this router with a process id of #42. ! network 16.1.1.0 0.0.0.255 area 0.0.0.2 ! ! This ties to the ip network address for the ethernet 0 interface. This places ! that address in OSPF area #2. ! network 17.1.1.0 0.0.0.255 area 0.0.0.0 ! ! This ties to the ip network address for the serial 0 interface. This places ! that address in OSPF area #0. ! end BRUTL#show config ! version 10.0 ! ! This is the version of the DECbrouter 90 code I used. ! interface Ethernet0 ! ip address 18.1.1.252 255.255.255.0 ! ! This IP address enables OSPF routing on this interface. ! interface Serial0 ! encapsulation frame-relay ! ! This command enables Frame Relay encapsulation running CHDLC. ! frame-relay lmi-type ansi ! ! This command sets up the LMI type whether it be CISCO, ANSI or CCITT. You ! need to ask your frame relay service provide what this should be configured ! for. ! keepalive 15 ! ! This is needed for LMI heart beat signals. ! interface Serial0.1 point-to-point ! ! This command configures a subinterface and allows the DBR90 to treat FR as a ! WAN circuit instead of a LAN. ! ip address 17.1.1.252 255.255.255.0 ! ! This IP address enables OSPF routing on this subinterface. ! frame-relay interface-dlci 100 ! ! There is NO requirement to map to the remote IP address (17.1.1.251) because ! this subinterface is treated as a WAN circuit. So we just need to map to the ! DLCI. 100 is the DLCI going to the remote router. ! router ospf 42 ! ! This command enables OSPF routing on this router with a process id of #42. ! network 18.1.1.0 0.0.0.255 area 0.0.0.1 ! ! This ties to the ip network address for the ethernet 0 interface. This places ! that address in OSPF area #1. ! network 17.1.1.0 0.0.0.255 area 0.0.0.0 ! ! This ties to the ip network address for the serial 0 interface. This places ! that address in OSPF area #0. ! end BRUTK#show ip route Codes: I - IGRP derived, R - RIP derived, O - OSPF derived C - connected, S - static, E - EGP derived, B - BGP derived i - IS-IS derived, D - EIGRP derived * - candidate default route, IA - OSPF inter area route E1 - OSPF external type 1 route, E2 - OSPF external type 2 route L1 - IS-IS level-1 route, L2 - IS-IS level-2 route EX - EIGRP external route Gateway of last resort is not set 16.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets C 16.1.1.0 is directly connected, Ethernet0 17.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets C 17.1.1.0 is directly connected, Serial0.1 18.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets O IA 18.1.1.0 [110/1572] via 17.1.1.252, 0:03:53, Serial0.1 BRUTK#show ip ospf data OSPF Router with ID (17.1.1.251) (Process ID 69) Router Link States (Area 0.0.0.0) Link ID ADV Router Age Seq# Checksum Link count 18.1.1.252 18.1.1.252 252 0x80000003 0xAA3 2 17.1.1.251 17.1.1.251 249 0x80000003 0x337D 2 Summary Net Link States (Area 0.0.0.0) Link ID ADV Router Age Seq# Checksum 18.1.1.0 18.1.1.252 412 0x80000001 0x2EFF 16.1.1.0 17.1.1.251 259 0x80000001 0x57DA Router Link States (Area 0.0.0.2) Link ID ADV Router Age Seq# Checksum Link count 17.1.1.251 17.1.1.251 259 0x80000002 0xA472 1 Summary Net Link States (Area 0.0.0.2) Link ID ADV Router Age Seq# Checksum 18.1.1.0 17.1.1.251 239 0x80000001 0x7897 17.1.1.0 17.1.1.251 261 0x80000001 0x21F9 BRUTL#show ip route Codes: I - IGRP derived, R - RIP derived, O - OSPF derived C - connected, S - static, E - EGP derived, B - BGP derived i - IS-IS derived, D - EIGRP derived * - candidate default route, IA - OSPF inter area route E1 - OSPF external type 1 route, E2 - OSPF external type 2 route L1 - IS-IS level-1 route, L2 - IS-IS level-2 route EX - EIGRP external route Gateway of last resort is not set 16.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets O IA 16.1.1.0 [110/1572] via 17.1.1.251, 0:03:26, Serial0.1 17.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets C 17.1.1.0 is directly connected, Serial0.1 18.0.0.0 is subnetted (mask is 255.255.255.0), 1 subnets C 18.1.1.0 is directly connected, Ethernet0 BRUTL#show ip ospf data OSPF Router with ID (18.1.1.252) (Process ID 69) Router Link States (Area 0.0.0.0) Link ID ADV Router Age Seq# Checksum Link count 18.1.1.252 18.1.1.252 226 0x80000003 0xAA3 2 17.1.1.251 17.1.1.251 225 0x80000003 0x337D 2 Summary Net Link States (Area 0.0.0.0) Link ID ADV Router Age Seq# Checksum 18.1.1.0 18.1.1.252 386 0x80000001 0x2EFF 16.1.1.0 17.1.1.251 235 0x80000001 0x57DA Router Link States (Area 0.0.0.1) Link ID ADV Router Age Seq# Checksum Link count 18.1.1.252 18.1.1.252 382 0x80000002 0x8C84 1 Summary Net Link States (Area 0.0.0.1) Link ID ADV Router Age Seq# Checksum 16.1.1.0 18.1.1.252 212 0x80000001 0x838C 17.1.1.0 18.1.1.252 388 0x80000001 0x1207