MPLS routers... eigrp issue

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Dec 14th, 2007
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Our new MPLS wan solution (which is replacing a flat ATM solution) has hit a speed-bump.

We'd like to make our network the default destination for all unknown traffic from all branches (BTW, all internet access and server stacks are here). When the border router (an 2811) was connected to Bell's CE router at the first remote site, and the eigrp network commands were added, the routing table was properly populated... with one exception:

The "default-network" command, issued on our border router (a 3825) did not get sent along with the rest of the updates.

To put this in perspective... the 3825 uses /29 on int g0/0, and /30 on g0/1, connecting to the bell router. So I entered the def-network on the 3825. Anything jump out at anyone?

Since this didn't work, I removed the def-net and entered these commands:

ip route g0/0

router eigrp 1


This also did not pass the network to the remote router, as expected.

What am I missing here gents? Any insights?

Network layout attached.

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Danilo Dy Sun, 12/16/2007 - 07:07
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Please post your diagram in JPG format so that all of us can see it.



mikearama Mon, 12/17/2007 - 10:50
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Attached as jpg.

I've also attached the config / ip route of our 3825.

Let me know what you think is missing to get a default network to the remote 2811.



royalblues Mon, 12/17/2007 - 12:27
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You do not seem to be running any eigrp between the 3835 and the remote router.

You woulod need to run a GRE tunnel between the 3825 and the 2811 using the MPLS as transport and run EIGRP on top of it

once you have done this, you can see the default-network being set at the remote 2811



mikearama Wed, 12/19/2007 - 06:54
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This is the config before the install of the remote 2811 (or after its removal). When it's added, there is an entry for the remote network, and the routing table is populated on the remote 2811... just the default route back is missing.

As for the gre tunnels... we have exactly 10 sites, and we went with the mpls solution to incorporate a full mesh. I can't remember the equation (n squared -n?), but that's a tonne of tunnels. There has to be another option.

For example, since the default-network command didn't work on our border 3825 router, nor the ip route g0/1 command coupled with network under eigrp, might this work:

int g0/1

ip summary-address eigrp 1 255

Would that not spread this route throughout our WAN, but since the cost is 255, prevent it from being used locally on the 3825?


Richard Burts Wed, 12/19/2007 - 07:25
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It has been quite a while since I used it, but my memory of the default network command is that it needs to point to a classful network and not to a subnet. Instead of using as the default network I suggest try using Give that a try and let us know what happens.

With administrative distance of 255 I do not believe that the route will be advertised and certainly will not be used locally.




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