Eigrp, supernet and 5500 RSM

[tgdaly]

I have a Catalyst 5500 with a RSM running version 11.x IOS.

One Vlan is configured with supernet of 192.168.20 /22.

Another Vlan with a subnet of 192.168.40 /29 is used to connect two other routers.

Other Vlans are configured with standard network, eg 192.168.2.0 /24, 192.168.3.0 /24

My problem is that while the standard networks are advertised to the other routers the supernet is not.

Does any know any reason for this not to work?

Also I have another router connected to the supernet and this is also learning routes via the RSM.

[mark-obrien]

I'm not sure how EIGRP is supposed to work here, but definitely make sure you have the "ip classless" command in all of your routers.

HTH

Mark

[tgdaly]

Mark,

ip classless is configured, as is no auto-summary.

The supernet is a connected network and under eigrp I have "redistribute connected".

This router is running version 11.x of the IOS and under eigrp I have "network 192.168.80.0". It not until ver 12.x that I could add the network mask to this command. I don't know it this is the problem and I not in a position to test, however I would have thought that this is not the fix.

Tony

[bianderson]

Hi Tony,

What version of IOS is on the RSM? I would be looking at 11.2.20P IP Plus as a fairly stable platform. Under the router eigrp xxxx section in the config, try adding a network 192.168.20.0 statement (make sure that the third octet of this matches the third octet of the IP address configured on the VLAN interface, it doesn't seem to behave corectly if you don't. i.e. if it's interface VLAN32, and it's IP address is 192.168.21.13 255.255.252.0, make sure the EIGRP network statement is network 192.168.21.0. The /22 seems to get advertised correctly if you do this!). Redistribute connected seems to work a bit randomly on older IOS's. I've seen instances where on a router if a connected interface is not up/up as soon as the EIGRP process initialises, it doesn't get advertised whatever you try! (This was in early 12.0). With the RSM in a Cat 5500, depending on the actual physical port membership to the associated VLAN on the RSM, some timimg issues may cause the RSM to boot and initialise the EIGRP process before the physical ports are in a forwarding state.

Hope some of this helps.

Regards,

Bill.

[tgdaly]

Bill,

Thanks for your input (I put the wrong network statement in my last message). I don't have access to the exact ver at present.

Interface Vlan 20 = 192.168.23.5 255.255.252.0

eigrp has the following:

network 192.168.20.0

network 192.168.23.0

Maybe I need to remove the "network 192.168.20.0".

Tony

[bianderson]

Hi Tony,

On a neighbour router, that is learning routes from the RSM, is there any entry at all for the 192.168.20.0 /22 network?

Redistribute connected may be causing the problem. If you don't have too many VLAN interfaces in the RSM, you could maybe try removing the redist connected command and specify all of your subnets as network x.x.x.x statements. At least you will be able to use only 1 statement for all of the subnet routes from a single /24!

If this doesn't solve it, I would be looking at the IOS revision, as some Early 11.x IOS on the RSM was it bit flaky. I have had 11.2.20P running at a customer site for years now, doing the job with VLSM and EIGRP and I haven't has to touch the box.

Sorry I couldn't be more help.

Bill.

[ruwhite]

Note the network statement has no bearing on what the router actually advertises. The network statement tells EIGRP which interfaces to run on, EIGRP picks up the networks to advertise from the interface ip addresses.

Can you post a show ip eigrp topo, if it's not too big? I know there was a lot of flakiness over networks with masks shorter than the network statement for a while, until the introduction of CSCdj00824 (along with the regression defects from later on), and I'm not certain the code you're in has that. Can you put wildcard bits after the network statement?

network x.x.x.x y.y.y.y

?

:-)

Russ.W