EIGRP Classic & Named mode – Leak-maps

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… 🙂

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