MPLS workshop #5 – CE-PE connection using EIGRP
Last protocol I’ll be focusing on for CE-PE connection is EIGRP. As in OSPF redistributing routes from EIGRP to BGP and back to EIGRP makes them external from routing protocol perspective. Using BGP extended communities many characteristics including AS number, tags or metric components are passed between PE routers and allows reconstruction of prefix. If the EIGRP route is internal it’s redistributed back as internal if AS numbers on remote PE router matches the source one (it’s encoded using external community). Otherwise it’s redistributed as EIGRP external.
Basic configuration is quite simple and similar to OSPF configuration described before. For purpose of this part of lab Ethernet connection between R2 and R3 is disabled and Serial connection is introduced using Serial2/3 interface configured. This link will be VRF_C member.
Configuration of CE routers is as simple as standard EIGRP process
router eigrp 65002 network 10.0.23.0 0.0.0.255 no auto-summary
router eigrp 65002 network 10.0.0.10 0.0.0.0 network 10.0.50.0 0.0.0.255 no auto-summary
We advertise loopback only on R10. Now the PE part. As in OSPF we have to remember to redistribute between BGP and EIGRP. The customer EIGRP AS number is defined for particular VRF under address-family section.
router eigrp 65111 ! address-family ipv4 vrf VRF_C autonomous-system 65002 redistribute bgp 65111 metric 10000000 0 255 1 1500 network 10.0.23.0 0.0.0.255 no auto-summary exit-address-family no auto-summary ! router bgp 65111 address-family ipv4 vrf VRF_C no synchronization redistribute eigrp 65002 exit-address-family
router eigrp 65111 ! address-family ipv4 vrf VRF_C autonomous-system 65002 redistribute bgp 65111 metric 10000000 0 255 1 1500 network 10.0.50.0 0.0.0.255 no auto-summary exit-address-family no auto-summary ! router bgp 65111 ! address-family ipv4 vrf VRF_C no synchronization redistribute eigrp 65002 exit-address-family
First verification is if R2 is receiving prefixes advertised by R10
R2#show ip route eigrp Codes: L - local, C - connected, S - static, R - RIP, M - mobile, B - BGP D - EIGRP, EX - EIGRP external, O - OSPF, IA - OSPF inter area N1 - OSPF NSSA external type 1, N2 - OSPF NSSA external type 2 E1 - OSPF external type 1, E2 - OSPF external type 2 i - IS-IS, su - IS-IS summary, L1 - IS-IS level-1, L2 - IS-IS level-2 ia - IS-IS inter area, * - candidate default, U - per-user static route o - ODR, P - periodic downloaded static route, + - replicated route Gateway of last resort is not set 10.0.0.0/8 is variably subnetted, 5 subnets, 2 masks D 10.0.0.10/32 [90/2323456] via 10.0.23.3, 00:05:54, Serial2/3 D 10.0.50.0/24 [90/2195456] via 10.0.23.3, 00:05:54, Serial2/3
Same as for OSPF we can check how EIGRP prefix attributes are converted into BGP extended community
R5#show ip bgp vpnv4 vrf VRF_C 10.0.0.10/32 BGP routing table entry for 65002:1:10.0.0.10/32, version 66 Paths: (1 available, best #1, table VRF_C) Advertised to update-groups: 1 Local 10.0.50.10 from 0.0.0.0 (10.0.0.5) Origin incomplete, metric 409600, localpref 100, weight 32768, valid, sourced, best Extended Community: RT:65002:1 Cost:pre-bestpath:128:409600 0x8800:32768:0 0x8801:65002:153600 0x8802:65281:256000 0x8803:65281:1500 mpls labels in/out 23/nolabel
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