This feature is mostly used with the hub and spoke topologies. Routers at the spoke sites are configured as stubs ensuring they the spoke sites don’t act as a transit path for the traffic.
A stub router will inform in EIGRP Hello packets that it has stub feature enabled and hence no queries are sent to stub router for any routes.
Related – EIGRP Packet Types
This is one way to tackle the well-known stuck-in-active issues in EIGRP networks.
Let us use the topology below to configure it’s a feature on Router 2.
In the topology above we have formed EIGRP neighborship between Router 1 & 2 as below:
H Address Interface Hold Uptime SRTT RTO Q Cnt Seq Num
0 22.214.171.124 Fa0/0 13 00:04:25 107 642 0 7
We have used the following configuration on R2:
network 126.96.36.199 0.0.0.0
network 188.8.131.52 0.0.0.3
redistribute static metric 1000 1 255 1 1500
ip address 184.108.40.206 255.255.255.255
ip address 220.127.116.11 255.255.255.252
ip address 18.104.22.168 255.255.255.0
Now we will configure EIGRP Stub feature on R2 with following options and check the EIGRP routes on R1 accordingly.
- Eigrp stub Connected
- Eigrp stub static
- Eigrp stub receive-only
- Eigrp stub redistributed
1: CONFIGURING EIGRP STUB CONNECTED
Only connected subnet 22.214.171.124 is advertised to R1.Though 126.96.36.199/24 is also connected network but is not advertised as it isn’t advertised under EIGRP process.
188.8.131.52/32 is subnetted, 1 subnets
D 184.108.40.206 [90/156160] via 220.127.116.11, 00:00:06, FastEthernet0/0
2: CONFIGURING EIGRP STUB STATIC
Only the static route to 18.104.22.168 is seen as advertised to R1.
D EX 22.214.171.124 [170/2562816] via 126.96.36.199, 00:00:07, FastEthernet0/0
3: EIGRP STUB RECEIVE-ONLY
No route is advertised to R1.
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
+ – replicated route, % – next hop override
Gateway of last resort is not set
4: EIGRP STUB REDISTRIBUTED
Only the redistribute static route is seen to be advertised.
D EX 188.8.131.52 [170/2562816] via 184.108.40.206, 00:01:07, FastEthernet0/0