SNA and IP on the same VLAN Etherswitch

omarmontes · ‎03-05-2007

Hi guys, I have the following issue, hope you could help:

Im using this router 2800 with an Etherswitch card. According to the Cisco website you can configure DLSw in this card using:

Q. Do the Cisco EtherSwitch HWICs support data-link switching plus (DLSW+)?

A. Yes, DLSW+ is supported on the Cisco EtherSwitch HWICs. Refer to the following sample configuration for enabling DLSW+:

bridge irb

!

dlsw local-peer peer-id 131.108.39.1

dlsw remote-peer 0 tcp 131.108.39.2

dlsw bridge-group 1

!

interface Vlan3

no ip address

bridge-group 1

bridge-group 1 spanning-disabled

!

bridge 1 protocol ieee

call rsvp-sync

I have alse IP users, so I guess we can use a seperate interface Vlan (with an IP address configured) for those IP users.

The issue here is that those SNA host also talk IP, how can I work this out? The problem is that when you enter the " bridge-group 1" command on the interface vlan used for SNA, the IP comunication in the vlan is interrupted, so I can't have both (IP and SNA) on the same vlan.

What we used to have was a router and an external switch. On the FE of the router we succesfully configured IP and SNA commands, and in the external switch we could have a mix of IP and SNA users. We are trying to do the same thing but with an etherswitch card.

Any help apretiated.

Richard Burts · ‎03-05-2007

Omar

I am puzzled about a couple things in your post. Are you saying that if VLAN 3 has an IP address and you add bridge-group 1 to the VLAN interface that IP processing is interrupted? I would think that should work.

The example shows VLAN 3 with no ip address. Are you perhaps also entering that command when you add the bridge-group command? That would certainly explain the interruption in IP processing.

There is another aspect of the example to consider. You show the example including bridge irb. IRB usually includes an interface BVI. Is there a BVI in the example and you did not include it? Did you configure the BVI when you were trying to follow the example? The BVI is another approach to bridging and routing on the same interface.

HTH

Rick

HTH

Rick

omarmontes · ‎03-05-2007

Thanks Rick:

In my actual configuration, when you have an interface vlan with an ip address all works just fine, but just after entering the "bridge-group 1" command the ip communication stops (in example, a ping to that interface would stop).

And yes, it turns out DLSw and IP can?t live togheter with etherswitch (http://www.cisco.com/en/US/tech/tk331/tk336/technologies_white_paper0900aecd80160aed.shtml) but there is a workaroung, and just like you suggested, it involves IRB.

In the example I posted about DLSw and etherswitch, there is a "Bridge irb" command, but there's no interface BVI, I think they left it out in a copy/paste mistake or something, because I wrote it exactly as it's in the cisco site.

Finally, I tried the workaround mentioned in the above link, using the bride-group 1 command in the int vlan and the ip addressing in the BVI, it seems to work but I'll have to give it a try using SNA devices (wich I don't have right now) It should work though.

Thanks a lot for the pointer :D