© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-1 MPLS VPN Implementation Configuring Small-Scale Routing Protocols Between PE and CE Routers

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-2 Outline Overview Configuring PE-CE Routing Protocols Selecting the VRF Routing Context for BGP Configuring Per-VRF Static Routes Configuring RIP PE-CE Routing Configuring EIGRP PE-CE Routing Configuring SOO for EIGRP PE-CE Loop Prevention Summary

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-3 PE-CE Routing Protocols PE-CE routing protocols are configured for individual VRFs. Per-VRF routing protocols can be configured in two ways: –Per-VRF parameters are specified in routing contexts, which are selected with the address-family command. –A separate OSPF process has to be started for each VRF. Prior to Cisco IOS Release 12.3(4)T, the overall number of routing processes per router was limited to 32, of which only 28 were available for VRF assignment.

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-4 router bgp as-number address-family ipv4 vrf vrf-name... Non-BGP redistribution... Router(config)# Select the per-VRF BGP context with the address-family command. Configure CE External Border Gateway Protocol neighbors in VRF context, not in global BGP configuration. All non-BGP per-VRF routes have to be redistributed into a per-VRF BGP context to be propagated by MP-BGP to other PE routers. Configuring the VRF Routing Context Within BGP

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-5 ip route vrf Customer_ABC serial0/ ! router bgp address-family ipv4 vrf Customer_ABC redistribute static Configuring Per-VRF Static Routes ip route vrf vrf-name prefix mask [interface interface- number] [next-hop-address] Router(config)# This command configures per-VRF static routes. The route is entered in the VRF table. You must specify a next-hop IP address if you are not using a point-to-point interface. Sample router configuration:

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-6 Configuring RIP PE-CE Routing A routing context is configured for each VRF running RIP. RIP parameters have to be specified in the VRF. Some parameters configured in the RIP process are propagated to routing contexts (for example, RIP version). Only RIPv2 is supported.

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-7 router rip version 2 address-family ipv4 vrf vrf-name redistribute bgp as-number metric transparent Router(config)# Configuring RIP PE-CE Routing: RIP Metric Propagation BGP routes must be redistributed back into RIP. The RIP hop count has to be manually set for routes redistributed into RIP. For end-to-end RIP networks, the following applies: –On the sending end, the RIP hop count is copied into the BGP MED. –On the receiving end, the metric transparent option copies the BGP MED into the RIP hop count, resulting in a consistent end-to- end RIP hop count. When you are using RIP with other protocols, the metric must be manually set.

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-8 Configuring RIP PE-CE Routing: Example

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-9 Provides EIGRP with the capability to redistribute routes through a VPN cloud Requires configuration of only the PE routers Imposes no upgrade or configuration changes to customer equipment Supports SOO capabilities to filter VPN traffic Configuring EIGRP PE-CE Routing

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-10 router eigrp process-id address-family ipv4 vrf vrf-name autonomous-system as-number redistribute bgp as-number metric metric-value Router(config )# Configuring EIGRP PE-CE Routing: EIGRP Metric Propagation Enables the EIGRP AS number of the CE under the address family. Configures per-instance AS number. Configures router redistribution. External routes received without the configured metric are not to be advertised to the CE router. –The metric can be configured in the redistribute statement using the redistribute command or configured with the default- metric command.

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-11 Configuring EIGRP PE-CE Routing: Example

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-12 Implementing EIGRP SOO for Loop Prevention

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-13 The SOO extended community can be used to prevent loops in dual-homed scenarios. All PE routers supporting EIGRP MPLS VPNs must support the SOO extended community. A unique SOO value must be configured for each VPN site. This value must be used on the PE-CE interface. The SOO attribute is configured through a route- map command. Implementing EIGRP SOO for Loop Prevention (Cont.)

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-14 route-map name permit seq set extcommunity soo extended-community-value Router(config)# Creates a route map that sets the SOO attribute ip vrf forwarding vrf-name ip vrf sitemap route-map-name ip address ip-address subnet-mask Router(config-if)# Applies a route map that sets SOO extended community attribute to inbound routing updates received from this interface Implementing EIGRP SOO for Loop Prevention (Cont.)

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-15 Implementing EIGRP SOO for Loop Prevention (Cont.)

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-16 Summary The per-VRF routing protocols can be configured in two ways: as individual address families belonging to the same routing process or as separate routing processes. Use the address-family ipv4 vrf vrf-name command to select the VRF routing context. Use the ip route vrf command to establish static routes. Use the address-family ipv4 vrf vrf-name command to start the configuration of individual routing context. Use the redistribute command to configure the metric that is copied into the MED attribute of the BGP route. Use the SOO extended community to prevent loops in EIGRP dual-homed scenarios.

© 2006 Cisco Systems, Inc. All rights reserved. MPLS v2.2—5-17