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Manual EIGRP Summarisation (where to do it)

------rtr7-----------rtr10----------rtr4----------

The line off rtr7 is an ethernet network of 172.16.5.0/29

Between rtr7 and rtr10 is a /24 WAN link and runs EIGRP.

Between rtr10 and rtr4 is an ethernet network /24 running RIPv1

rtr10 redists EIGRP into RIPv1. (all networks are /24 except the /29 off rtr7)

So, i know that I have to manually summarise the /29 into a /24 so that RIPv1 will accpet the route.

Question is, where is best to do it. Assume no other 172.16.5.0 networks in the routing table.

The logical place to do this is off the rtr7 WAN line to rtr10 with the command "ip summary-address eigrp 65001 172.16.5.0 255.255.255.0"

but, i could also just summarise this on the ethernet from rtr10 to rtr4 on even the WAN link off rtr10 back to rtr7. I could even create a loopback interface with no ip address on rtr10 and put the summarisation on this interface.

If i summarise on a loopback with no ip address on rtr10, i dont send a summary route back to rtr7 and it just creates the null0 route on rtr10 and summarised a /24 for the RIPv1 redistribution.

Surely, this is neater for the routing table, to hap on a redistribution router a loopback doing all the summarsation?

HELP :)))))))))))))))))))))

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Re: Manual EIGRP Summarisation (where to do it)

Any of the above options would work, but I'd probably summarize at the EIGRP/RIPv1 border, on the outbound interface towards RTR4 on RTR10. My reasoning would be that it doesn't make any sense to take routing information out of eigrp before it is pushed into RIP, since you might have other /29's added later that will need to be routed to, and could cause yourself problems if you summarize at the RTR7/RTR10 interface.

Russ.W

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