Back from my vacation in Greece! Took a break from everything network-related to recharge but now i’m all set to keep crunching both labs & books. Currently fighting my way thru “IP Routing on IOS, IOS XE and IOS XR – An essential guide to understanding & implementing IP Routing Protocols” (2.1k pages – yikes… ). Trying to get back into the groove with an easier lab on EIGRP Leak-maps down below:
Requirements:
- Configure Classic mode on R4 & R5 with AS100 and enable over both ethernet + DMVPN
- Configure Named mode on R1, R3, R6 & R7 with AS200 and enable over 155.1.0.0/16
- Configure loopbacks on R4 and redistribute to EIGRP
- Lo40 -4.0.0.4/24
- Lo41 – 4.0.1.4/24
- Configure loopbacks on R6 and redistribute to EIGRP
- Lo60 – 6.0.0.6/24
- Lo61 – 6.0.1.6/24
- Configure default summary-routes on R4 & R6 to be advertised instead of Loopbacks
- Configure a leak-map on R4 for traffic to Lo40 to be routed via DMVPN
- Configure a leak-map on R6 for traffic to Lo60 to be routed via R3 from R1
- If the DMVPN is down, traffic should still be rerouted on the backup-path
Let’s start with the easy part and configure EIGRP, Loopbacks and redistribution:
!! General ! R4 & R5 router eigrp 100 network 155.1.0.0 0.0.255.255 network 150.0.0.0 0.0.0.255 ! R1, R3, R6, R7 router eigrp MULTI-AF address-family ipv4 auto 200 network 155.1.0.0 0.0.255.255 !! Loopbacks ! R4 int Lo40 ip add 4.0.0.4 255.255.255.0 int Lo41 ip add 4.0.1.4 255.255.255.0 router eigrp 100 redistribute connected ! R6 int Lo60 ip add 6.0.0.6 255.255.255.0 int Lo61 ip add 6.0.1.6 255.255.255.0 router eigrp MULTI-AF address-family ipv4 auto 200 topology base redistribute connected
We should now have the baseline working.
R5#sh ip route eigrp | beg Gate Gateway of last resort is not set 4.0.0.0/24 is subnetted, 2 subnets D EX 4.0.0.0 [170/130816] via 155.1.45.4, 00:18:52, GigabitEthernet1.45 D EX 4.0.1.0 [170/130816] via 155.1.45.4, 00:18:52, GigabitEthernet1.45 150.1.0.0/32 is subnetted, 2 subnets D EX 150.1.4.4 [170/130816] via 155.1.45.4, 00:18:52, GigabitEthernet1.45 R1#sh ip route eigrp | beg Gate Gateway of last resort is not set 6.0.0.0/24 is subnetted, 2 subnets D EX 6.0.0.0 [170/10880] via 155.1.146.6, 00:14:51, GigabitEthernet1.146 D EX 6.0.1.0 [170/10880] via 155.1.146.6, 00:14:51, GigabitEthernet1.146 150.1.0.0/32 is subnetted, 2 subnets D EX 150.1.6.6 [170/10880] via 155.1.146.6, 00:14:51, GigabitEthernet1.146 155.1.0.0/16 is variably subnetted, 10 subnets, 2 masks D 155.1.7.0/24 [90/20480] via 155.1.146.6, 00:15:53, GigabitEthernet1.146 [90/20480] via 155.1.13.3, 00:15:53, GigabitEthernet1.13 D 155.1.37.0/24 [90/15360] via 155.1.13.3, 00:15:53, GigabitEthernet1.13 D 155.1.67.0/24 [90/15360] via 155.1.146.6, 00:15:53, GigabitEthernet1.146 D 155.1.79.0/24 [90/20480] via 155.1.146.6, 00:15:53, GigabitEthernet1.146 [90/20480] via 155.1.13.3, 00:15:53, GigabitEthernet1.13
Let’s add our summary-routes to R4 & R6:
!! Summary default-route ! R4 int Gi1.45 ip summary-address eigrp 100 0.0.0.0 0.0.0.0 int Tu0 ip summary-address eigrp 100 0.0.0.0 0.0.0.0 ! R6 router eigrp MULTI-AF address-family ipv4 auto 200 af-interface Gi1.67 summary-address 0.0.0.0 0.0.0.0 af-interface Gi1.146 summary-address 0.0.0.0 0.0.0.0
As we’re doing summarization our loopbacks advertisements will be suppressed and replaced with an internal 0.0.0.0/0 route:
R1#sh ip route eigrp | beg Gate Gateway of last resort is 155.1.146.6 to network 0.0.0.0 D* 0.0.0.0/0 [90/10880] via 155.1.146.6, 00:01:30, GigabitEthernet1.146 155.1.0.0/16 is variably subnetted, 10 subnets, 2 masks D 155.1.7.0/24 [90/20480] via 155.1.13.3, 00:01:30, GigabitEthernet1.13 D 155.1.37.0/24 [90/15360] via 155.1.13.3, 00:01:30, GigabitEthernet1.13 D 155.1.67.0/24 [90/20480] via 155.1.13.3, 00:01:30, GigabitEthernet1.13 D 155.1.79.0/24 [90/20480] via 155.1.13.3, 00:01:30, GigabitEthernet1.13 R5#sh ip route eigrp | beg Gate Gateway of last resort is 155.1.45.4 to network 0.0.0.0 D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:00:20, GigabitEthernet1.45
Next step is to use a leak-map so traffic going to R4s loopback is routed via DMVPN-cloud instead of the ethernet-segment. This will be easily solved by advertising that specific route out on our Tu0-interface together with our default-route. Longest-match makes routers prefer our specific-route instead of the default to get to 4.0.0.4. To implement this we use a “leak-map”, I found it in the official DOC here & here.
!! Leak-map ! R4 ip prefix-list LOOP permit 4.0.0.4/24 route-map LEAK permit 10 match ip add prefix-list LOOP int Tu0 ip summary-address eigrp 100 0.0.0.0 0.0.0.0 leak-map LEAK
Neighbors will do a graceful-restart and then the results should be visible in R5:
R5#sh ip route eigrp | beg Gate Gateway of last resort is 155.1.45.4 to network 0.0.0.0 D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:07:01, GigabitEthernet1.45 4.0.0.0/24 is subnetted, 1 subnets D EX 4.0.0.0 [170/25984000] via 155.1.0.4, 00:00:05, Tunnel0 R5#ping 4.0.0.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 4.0.0.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/6 ms
If we close our Tunnel-interface traffic will still be routed over the default-route to Gi1.45.
! R4 int Tu0 shut R5#sh ip route eigrp | beg Gate Gateway of last resort is 155.1.45.4 to network 0.0.0.0 D* 0.0.0.0/0 [90/3072] via 155.1.45.4, 00:09:36, GigabitEthernet1.45 R5#ping 4.0.0.4 Type escape sequence to abort. Sending 5, 100-byte ICMP Echos to 4.0.0.4, timeout is 2 seconds: !!!!! Success rate is 100 percent (5/5), round-trip min/avg/max = 4/4/6 ms
Sweet! Now we just have to do the same thing in R6, by leaking our route on the Gi1.67-interface R1 will prefer the route to R3 over going directly to R6 for reaching 6.0.0.0/24.
!! Leak-map ! R6 ip prefix-list LOOP permit 6.0.0.6/24 route-map LEAK permit 10 match ip add prefix-list LOOP router eigrp MULTI-AF address-family ipv4 auto 200 af-interface gi1.67 summary-address 0.0.0.0 0.0.0.0 leak-map LEAK
Let’s check R1 again:
R1#sh ip route eigrp | beg Gate Gateway of last resort is 155.1.146.6 to network 0.0.0.0 D* 0.0.0.0/0 [90/10880] via 155.1.146.6, 00:11:33, GigabitEthernet1.146 6.0.0.0/24 is subnetted, 1 subnets D EX 6.0.0.0 [170/21120] via 155.1.13.3, 00:00:20, GigabitEthernet1.13 155.1.0.0/16 is variably subnetted, 10 subnets, 2 masks D 155.1.7.0/24 [90/20480] via 155.1.13.3, 00:11:33, GigabitEthernet1.13 D 155.1.37.0/24 [90/15360] via 155.1.13.3, 00:11:33, GigabitEthernet1.13 D 155.1.67.0/24 [90/20480] via 155.1.13.3, 00:11:33, GigabitEthernet1.13 D 155.1.79.0/24 [90/20480] via 155.1.13.3, 00:11:33, GigabitEthernet1.13
All is good! I’m really starting to like EIGRP’s named mode the more I use it, the classic feels so clunky now. Until next time… 🙂