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Community Member

Remote network is disappeared from routing table

Hi all,

I have problem with EIGRP routing table. See the topology as below:

Router D <--> Router C <--> Router B <--> Router A

|

|

Router E <--> Router F <--> Router G

From the above topology: Router A, B, and G are member of AS 2. Router D & E are member of AS 1 and I made redistribution on Router C & F between AS 2 & 1. Below are info on each router:

- Router A

f0: 10.100.100.4 /24

s0: 192.168.21.1 /24 (Leased Line 128K to Router B)

- Router B

f0: 10.100.103.2 /24

s0: 192.168.21.2 /24 (Leased Line 128K to Router A)

s1: 192.168.22.1 /24 (IVSAT 128K to Router C)

- Router C

f0: 172.16.7.225 /23

s0: 192.168.22.2 /24 (IVSAT 128K to Router B)

Redistribute into EIGRP 1

network 10.0.0.0

network 192.168.21.0

network 192.168.22.0

Redistribute into EIGRP 2

network 172.16.0.0

- Router D

f0: 172.16.7.224 /23

s0: 192.168.254.14 /30 (Microwave 128K to Router E)

- Router E

f0: 172.16.3.224 /23

s0: 192.168.254.13 /30 (Microwave 128K to Router D)

- Router F

f0: 172.16.3.225 /23

s0: 192.168.20.2 /24 (IPLC 128K to Router G)

Redistribute into EIGRP 1

network 10.0.0.0

network 192.168.20.0

Redistribute into EIGRP 2

network 172.16.0.0

- Router G

f0: 10.100.100.5 /24

s0: 192.168.20.1 /24 (IPLC 128K to Router F)

All of the routers used "no auto-summary", "ip classless".

When the link between router B and C is down, I can see network 172.16.2.0 and 172.16.6.0 on Router G. And when the link between Router F and G is down, I can also see network 172.16.2.0 /23 and 172.16.6.0 on Router B BUT on Router A I can see only 172.16.6.0 so that network 172.16.2.0 is disappeared from routing table.

What is the possible cause? and Why? I have tried to check the configuration on all of the routers but I can't see the root cause. Help me please. Thank you very much in advance.

Regards,

Worapoj R.

1 REPLY
Community Member

Re: Remote network is disappeared from routing table

I drew all this out before reading the question. You never state which interfaces the 172.16.6.0 and 172.16.2.0 networks join in.

As well, the math doesn't work right on Router A Int F0 and Router G Int F0--are they connected? If not, the discontiguous subnets don't help matters.

In any case, when stuff isn't working right, look down the OSI model, not up.

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