EIGRP

[saidfrh]

Hi,

I have three routers in a mesh: San1, West and San2.

Routers San1 and West are connected via serial.

Router West and San2 are connected serial.

Router San 1 and San 2 are connected via Ethernet.

EIGRP is the routing protocol.

No-auto summary is configured for all routers.

San2, sh "ip int br":

Ethernet0 193.168.1.2 YES manual up up

Serial0 193.168.64.5 YES manual up up

West, sh "ip int br":

Serial1/0 193.168.64.2 YES manual up up

Serial1/1 193.168.64.6 YES manual up up

San1, sh "ip int br":

Ethernet0 193.168.1.1 YES manual up up

Serial0 193.168.64.1 YES manual up up

Why the following gets displayed?

On San1, "IP-EIGRP: Neighbor 193.168.64.6 not on common subnet for Serial0" is displayed.

On West, "IP-EIGRP(Default-IP-Routing-Table:100): Neighbor 193.168.64.5 n

ot on common subnet for Serial1/0"

On San2, IP-EIGRP: "Neighbor 193.168.64.2 not on common subnet for Serial0"

Thanks.

Said

[sundar.palaniappan]

Appears, the serial cables on the West router is reversed. Move the serial cables around on the West router and that should stop the error. Morevoer, you wouldn't be having IP connectivity now from West to San1 & San2 as the p-t-p links are on different subnet.

Just as the error implies, the router tells you there is a device on the far end of the connection which isn't on the same IP subnet as it's interface is on.

Let me know if you had questions.

--Sundar

[saidfrh]

Sundar,

Why would DCE and DTE serial connections have any effect on the operation of the routers? As I know, DCE connected routers are to provide clocking.

As for subnets,

193.168.64.0 network

193.168.64.1 host

193.168.64.2 host

193.168.64.3 broadcast

193.168.64.4 network

193.168.64.5 host

193.168.64.6 host

193.168.64.7 broadcast

Could you explain. Thanks.

[autobot130]

Thats right.. those are correct host addresses, if you are using /30 subnets on both sides. The earlier message is suggesting you dont have netmasks matching on both sides.

[Richard Burts]

It would be helpful to get the output of show cdp neighbors on each of the routers. I believe that this would demonstrate the point that the earlier posts were making which is that the cables are not connected as intended.

Also the problem has nothing to do with DTE and DCE.

HTH

Rick

[sundar.palaniappan]

I am not sure if I understand your question correctly.

Anyway, DCE/DTE end isn't the problem here. If there was something wrong there then your interfaces wouldn't have come up.

The problem is the cable that you have coming from San1 is plugged into the Serial interface on West router to which you have assigned an IP address from subnet that's configured for the p-t-p link to San2.

HTH,

Sundar