eigrp stub connected summary redistributed

[rakeshvelagala]

Hi All,

Please advise on the below. 

In the routing table of R3, I have redistributed routes learnt from other Router. But they are not being advertised to other routers which are neighbors to R3.

1)Is my understanding of "eigrp stub connected summary redistributed" correct?

From the routing table, along with the connected and summary routes, it will also advertise the redistributed routes learnt?

2)I read from other blog that even if we use the connected/Static, there should be network statement to advertise them.(Is this correct?).

R3# sh run | s router eigrp
router eigrp 33
network 10.1.3.0 0.0.0.255
network 10.1.163.0 0.0.0.255
network 11.1.1.0 0.0.0.255
eigrp stub connected summary redistributed

Gateway of last resort is not set

10.0.0.0/8 is variably subnetted, 16 subnets, 2 masks
D 10.1.1.0/24 [90/27008000] via 11.1.1.1, 00:12:04, Tunnel23
D 10.1.2.0/24 [90/28288000] via 11.1.1.2, 00:12:04, Tunnel23
C 10.1.3.0/24 is directly connected, Loopback0
L 10.1.3.3/32 is directly connected, Loopback0
D EX 10.1.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
C 10.1.63.0/24 is directly connected, Ethernet0/1
L 10.1.63.3/32 is directly connected, Ethernet0/1
C 10.1.123.0/24 is directly connected, Ethernet0/0
L 10.1.123.3/32 is directly connected, Ethernet0/0
C 10.1.163.0/24 is directly connected, Serial4/2
L 10.1.163.3/32 is directly connected, Serial4/2
D EX 10.11.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
D EX 10.22.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
D EX 10.33.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
D EX 10.44.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
D EX 10.55.6.0/24 [170/2297856] via 10.1.163.6, 00:12:04, Serial4/2
11.0.0.0/8 is variably subnetted, 2 subnets, 2 masks
C 11.1.1.0/24 is directly connected, Tunnel23
L 11.1.1.3/32 is directly connected, Tunnel23

Thanks

[acampbell]

Hi,

The way you check if the EIGRP STUB feature is in operation is

show ip eigrp nei det

Look at the last line of the output to see the EIGRP STUB status

This link may be old but very descriptive:-

http://www.cisco.com/c/en/us/td/docs/ios/12_0s/feature/guide/eigrpstb.html

Regards

Alex

[Peter Paluch · Accepted solution]

Hi Rakesh,

1)Is my understanding of "eigrp stub connected summary redistributed" correct?

From the routing table, along with the connected and summary routes, it will also advertise the redistributed routes learnt?

Your understanding is not entirely correct on this point. The redistributed keyword refers to networks redistributed into EIGRP on the R3 itself. However, because the networks marked with "D EX" are being redistributed on a different router, and are simply learned by EIGRP on R3, the redistributed keyword does not apply to them. Remember, one of key behaviors of an EIGRP stub router is that it keeps all networks learned via EIGRP to itself and does not advertise them further. This perfectly applies to the "D EX" routes that are learned via EIGRP and so - because of the stub status - are not being advertised from R3 to other routers.

There is a possibility of configuring a leak-map argument to the eigrp stub command that would allow R3 to advertise selected EIGRP-learned routes even though it is a stub router. However, this command should be used judiciously, as by leaking the routes that would otherwise be suppressed, you are losing some of the advantages of the stub functionality.

2)I read from other blog that even if we use the connected/Static, there should be network statement to advertise them.(Is this correct?).

Yes, this is correct. For a directly connected network to be advertised by an EIGRP stub router, two conditions must be met:

1. The network must be added to EIGRP using the usual network command
2. The eigrp stub command must include the connected keyword or no type keywords at all (without type keywords, the default behavior is connected summary)

Similarly, for a static route to be advertised by an EIGRP stub router, two conditions must be met;

1. The network must be redistributed into EIGRP using the redistribute static command
2. The eigrp stub command must include the static or redistributed keywords

Best regards,
Peter