Had to do a lot labs for my CCIE LAB preparations…One of the interesting EIGRP Concept which I’m gonna post is with EIGRP leak-maps…
So basically, when EIGRP is enabled and we started advertising the routes, each network advertise will be received by the neighboring EIGRP router…
So what if we want to select the routes which we want to advertise when summarization is enabled… Summarization is useful if we just want a single network to be advertise…but what if a requirements is not to advertise a certain network address that belongs to the summarized network…
This can be done via a leak-map…had to explore a bit on classic EIGRP and Named EIGRP in order to elaborate more on leak-map…
I’m gonna used the below simple diagram to explore on this concept..
Below are the task that needs to be completed…
- Configure R1 as Classic EIGRP
- Configure R2 as Named EIGRP
- Configure Summary routes in R1. Allow Only Loopback 10 in R1 to be learned by R2.
- Configure Summary routes in R2. Allow only Loopback 20 in R2 to be learned by R1.
Configurations:
R1:
router eigrp 12
network 10.10.10.10 0.0.0.0
network 10.10.20.20 0.0.0.0
network 192.168.12.0
Named EIGRP Configurations:
R2:
router eigrp NAMED_R1-R2
!
address-family ipv4 unicast autonomous-system 12
!
topology base
exit-af-topology
network 20.20.10.10 0.0.0.0
network 20.20.20.20 0.0.0.0
network 192.168.12.0
exit-address-family
EIGRP neighbor verifications:
R1#show ip eigrp neighbors
EIGRP-IPv4 Neighbors for AS(12)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 192.168.12.2 Gi0/1 11 00:00:47 2 100 0 5
R2#show ip eigrp neighbors
EIGRP-IPv4 VR(NAMED_R1-R2) Address-Family Neighbors for AS(12)
H Address Interface Hold Uptime SRTT RTO Q Seq
(sec) (ms) Cnt Num
0 192.168.12.1 Gi0/1 12 00:00:28 1021 5000 0 4
R2#
EIGRp routing table without Summarization:
R1#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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
20.0.0.0/32 is subnetted, 2 subnets
D 20.20.10.10 [90/2848] via 192.168.12.2, 00:00:40, GigabitEthernet0/1
D 20.20.20.20 [90/2848] via 192.168.12.2, 00:00:33, GigabitEthernet0/1
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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/32 is subnetted, 2 subnets
D 10.10.10.10
[90/2570240] via 192.168.12.1, 00:00:56, GigabitEthernet0/1
D 10.10.20.20
[90/2570240] via 192.168.12.1, 00:00:56, GigabitEthernet0/1
R2#
First Condition is for R1 to leak only L10 to R2 and summary routes from R1 should be seen on R2:
Configs to apply:
int gigabitEthernet 0/1
ip summary-address eigrp 12 10.10.0.0/16 leak-map R1R2_Leak_Map
ip prefix-list R1_to_R2-Leak_Routes permit 10.10.10.10/32
route-map R1R2_Leak_Map
match ip address prefix-list R1_to_R2-Leak_Routes
R1#config t
Enter configuration commands, one per line. End with CNTL/Z.
R1(config)#int gigabitEthernet 0/1
R1(config-if)#ip summary-address eigrp 12 10.10.0.0/16 leak-map R1R2_Leak_Map
*Feb 12 11:55:17.688: %DUAL-5-NBRCHANGE: EIGRP-IPv4 12: Neighbor 192.168.12.2 (GigabitEthernet0/1) is resync: summary configured
R1(config-if)#
Used Prefix-list to filter the Loopback 20...
R1(config)#ip prefix-list R1_to_R2-Leak_Routes permit 10.10.10.10/32
Create the route-map ...
R1(config)#route-map R1R2_Leak_Map
R1(config-route-map)#match ip address prefix-list R1_to_R2-Leak_Routes
R1(config-route-map)#^Z
R1#
R1#
R1#
R1#
*Feb 12 11:57:05.672: %SYS-5-CONFIG_I: Configured from console by console
R1#
R1#
*Feb 12 11:57:14.552: %DUAL-5-NBRCHANGE: EIGRP-IPv4 12: Neighbor 192.168.12.2 (GigabitEthernet0/1) is resync: intf route configuration changed
Now checking R2 EIGRP Topology table:
R2#show ip eigrp topology
EIGRP-IPv4 VR(NAMED_R1-R2) Topology Table for AS(12)/ID(20.20.20.20)
Codes: P - Passive, A - Active, U - Update, Q - Query, R - Reply,
r - reply Status, s - sia Status
P 10.10.10.10/32, 1 successors, FD is 328990720
via 192.168.12.1 (328990720/327761920), GigabitEthernet0/1
P 192.168.12.0/24, 1 successors, FD is 1310720
via Connected, GigabitEthernet0/1
P 20.20.20.20/32, 1 successors, FD is 163840
via Connected, Loopback20
P 20.20.10.10/32, 1 successors, FD is 163840
via Connected, Loopback10
P 10.10.0.0/16, 1 successors, FD is 328990720
via 192.168.12.1 (328990720/327761920), GigabitEthernet0/1
R2#
It has only the topology entry for the summary routes from R1 and Loopback 10..
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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 10.10.0.0/16
[90/2570240] via 192.168.12.1, 00:08:39, GigabitEthernet0/1
D 10.10.10.10/32
[90/2570240] via 192.168.12.1, 00:06:57, GigabitEthernet0/1
R2#
Configure R2 to filter Loopback 10 and allow only Loopback 20 and enable summary routes...
Script:
router eigrp NAMED_R1-R2
!
address-family ipv4 unicast autonomous-system 12
!
af-interface GigabitEthernet0/1
summary-address 20.20.0.0 255.255.0.0 leak-map R2_R1_Leak_Map
exit-af-interface
ip prefix-list R2_R1_Leak_Routes permit 20.20.20.20/32
route-map R2_R1_Leak_Map
match ip address prefix-list R2_R1_Leak_Routes
Configurations applied on the device...
R2(config)#router eigrp NAMED_R1-R2
R2(config-router)# address-family ipv4 unicast autonomous-system 12
R2(config-router-af)#af-interface Gi0/1
R2(config-router-af-interface)#summary-address 20.20.0.0 255.255.0.0 leak-map R2_R1_Leak_Map
R2(config)#ip prefix-list R2_R1_Leak_Routes permit
R2(config)#ip prefix-list R2_R1_Leak_Routes permit 20.20.20.20/32
R2(config)#route-map R2_R1_Leak_Map
R2(config-route-map)#match ip address prefix-list R2_R1_Leak_Routes
R2#
*Feb 12 12:12:24.030: %SYS-5-CONFIG_I: Configured from console by console
*Feb 12 12:12:32.722: %DUAL-5-NBRCHANGE: EIGRP-IPv4 12: Neighbor 192.168.12.1 (GigabitEthernet0/1) is resync: intf route configuration changed
R2#
Now checking R1 EIGRP routes:
R1#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, H - NHRP, l - LISP
a - application route
+ - replicated route, % - next hop override, p - overrides from PfR
Gateway of last resort is not set
10.0.0.0/8 is variably subnetted, 3 subnets, 2 masks
D 10.10.0.0/16 is a summary, 00:17:28, Null0
20.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
D 20.20.0.0/16 [90/2848] via 192.168.12.2, 00:01:52, GigabitEthernet0/1
D 20.20.20.20/32
[90/2848] via 192.168.12.2, 00:00:36, GigabitEthernet0/1
R1#
As observed, we have the summary routes from R2 and Loopback 20...
NETWORK LESSON 
Leave a comment