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Routing Loop Problem

a problem happened which is a routing loop in eigrp

the problem was as follow

on R4 side

an ATM machine was connected to the R4 router with ip the Dekhila router had an ip it a default route through the serial of dekhila of serial connection between R4 and R3 the B.W. under the serial of R4 was 32 and the B.w under the R3 router was 1

(int ser x

bandwidth 1)

on R3 side

router eigrp with networks (which is the loopback) and network (which is the ethernet ip) and network (which is the voice segment) note that both 192 and 172 are done on sub interfaces of ethernet

the serial between R3 AND R2 is a link of 128 mbps and B.wW. on both serials is 128

the serial link between R3 and R1 is a 128 mbps and B.w under two serials is 128

a static route was done as follow on R3 to reach the ATM

ip route ser(on R3 of the link between R3 and R4)

on R1 side

which is the core router it had eigrp with network as well as networks of voice and data and loopback

a static route was configured as follow

ip route ser (ser of the link between R1 and R3)

the following happened

when i make traceroot to it goes throgh R1 , R3 , R2 , R3 , R2 and so on

while taking in acount that when i made a static route on R2 using the next hope address it worked correctly so why did the loop occur in the first case

Hall of Fame Super Silver

Re: Routing Loop Problem


I have looked at your drawing and read your description but I do not think that you have given us enough information to find the solution. The way that you describe the problem would seem that something on R3 was forwarding packets toward R2 when it should have been forwarding toward R4. In that situation I do not understand how a static on R2 would fix the problem.

If we are going to find the explanation we will need some more specific information. In particular we would need to see the output of show ip route from R3 in the situation where the problem exists and then the output of show ip route from R3 when the problem is fixed. It would also be helpful if you would post the exact syntax used on each of the routers to define the static routes.