MPLS LAB - PE to CE routing - EIGRP (same AS PE-CE)
January 14th, 2009 in CCIE SP, Security | tags: ,

In this post I will show how to configure EIGRP as the PE to CE routing protocol. The network used is the same as used in the rest of this series. You can see it below again :

MPLS

In this first example we are going to use the same AS number between the PE and CE router for EIGRP.

When using the same AS between the PE and CE router internal routes from one VPN site will be remain internal routes in other VPN sites.
When using the same AS between the PE and CE router external routes will remain external routes.

We are only going to configure VPN_A since the configuration for VPN_B is pretty much the same.

router R3’s config :

R3 :


router eigrp 21047
 no auto-summary
 !
 address-family ipv4 vrf VPN_A
 redistribute bgp 100 metric 10000 1 255 1 1500
 network 37.37.37.3 0.0.0.0
 no auto-summary
 autonomous-system 21047
 exit-address-family
!
router bgp 100
 no synchronization
 bgp router-id 3.3.3.3
 bgp log-neighbor-changes
 neighbor 6.6.6.6 remote-as 100
 neighbor 6.6.6.6 update-source Loopback0
 no auto-summary
 !
 address-family ipv4 vrf VPN_A
 redistribute eigrp 21047
 no auto-summary
 no synchronization
 exit-address-family

router R7’s config :

R7:


router eigrp 21047
 redistribute connected metric 10000 1 255 1 1500 route-map LO1
 network 7.7.7.7 0.0.0.0
 network 37.37.37.7 0.0.0.0
 no auto-summary
!
route-map LO1 permit 10
 match interface Loopback1
!
interface Loopback1
 ip address 77.77.77.77 255.255.255.255

Notice that I created a loopback 1 to show that redistributed routes (External routes) remain external on the other side of the VPN.

router R6’s config :

R6 :


router eigrp 21047
 no auto-summary
 !
 address-family ipv4 vrf VPN_A
 redistribute bgp 100 metric 10000 1 255 1 1500
 network 61.61.61.6 0.0.0.0
 no auto-summary
 autonomous-system 21047
 exit-address-family
!
router bgp 100
 no synchronization
 bgp router-id 6.6.6.6
 bgp log-neighbor-changes
 neighbor 3.3.3.3 remote-as 100
 neighbor 3.3.3.3 update-source Loopback0
 no auto-summary
 !
address-family ipv4 vrf VPN_A
 redistribute eigrp 21047
 no auto-summary
 no synchronization
 exit-address-family

router R11’s config :

R11 :


router eigrp 21047
 network 11.11.11.11 0.0.0.0
 network 61.61.61.11 0.0.0.0
 no auto-summary

Now let’s do a “sh ip route” on R11 :

R11 :


R11#sh ip route
Codes: 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

Gateway of last resort is not set

     37.0.0.0/24 is subnetted, 1 subnets
D       37.37.37.0 [90/30720] via 61.61.61.6, 00:13:12, FastEthernet2/0
     7.0.0.0/32 is subnetted, 1 subnets
D       7.7.7.7 [90/158720] via 61.61.61.6, 00:13:12, FastEthernet2/0
     77.0.0.0/32 is subnetted, 1 subnets
D EX    77.77.77.77 [170/261376] via 61.61.61.6, 00:09:45, FastEthernet2/0
     11.0.0.0/32 is subnetted, 1 subnets
C       11.11.11.11 is directly connected, Loopback0
     61.0.0.0/24 is subnetted, 1 subnets
C       61.61.61.0 is directly connected, FastEthernet2/0

As you can see above the internal EIGRP routes remain internal and the external route (the redistributed route from router R7’s loopback 1 interface) remains

external when using EIGRP with the same AS number between the PE and CE at different VPN sites.

In the next post I will show the configuration of EIGRP as the PE to CE routing protocol with different AS numbers.

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