dlsw (IBM sna) capabilities on a WS3750-X

[xavier.delcour]

Hi,

I am looking into the Cisco documentation and I did not find anything about it.

It is possible to use this switch has a dlsw gateway ?

Thanks for your help.

Regards,

Xavier

[Richard Burts · Accepted solution]

Xavier

I am not authoritative for this but I believe that DLSW is supported on router IOS and not on the Catalyst IOS for switches. I took a quick look at the Cisco feature navigator and I see DLSW support only on routers and not on switches.

HTH

Rick

[Leo Laohoo]

I agree with Rick.  DLSW is for routers only.

Switches won't have the support due to the "media" involved.

[vmiller]

What version of code?

i did a rough search with feature navigator, and generally, this feature is supported on routers, not so much on switches.

[xavier.delcour]

Hi,

At first thanks for your help and comments.

It will be with an IP Services license with a IOS 122-58.SE2.bin, we could also consider to use the 15.0 branch without any problems. I am also using the feature navigator but I do not really find anything about it.

I found also this link  https://supportforums.cisco.com/thread/2061672, as I never used DLSW until now I am reading everything I can on this protocol in order to understand how it works.

Regards,

Xavier

[vmiller]

Re ran navigator, Its router based except when you get into some Cat6000 stuff.

Try this :

From the navigator page, select search by feature.

filter by: Dlsw

you will get a list of platforms.

[xavier.delcour]

To be honest I first gave a look into it but since I didn't find any information about it, I decided to open this thread. I should have informed about it, sorry.

Thanks for your help.

[mwinnett · Accepted solution]

Xavier, IBM legacy devices run a layer 2 protocol llc2. The client (user pc, MS gateway etc) is configured to talk to the mac-address of the server (mainframe, as/400 etc). The client sends a test looking for the mac-address. When it gets a reply (test response) it sends an XID (exchange identifier). Assuming this is accepted, the client sends "sabme" to set the communications mode and the server accepts ("ua"). Now we have a llc2 connection and the devices can exchange sna frames. This all occurs at layer 2, no routing. Dlsw puts itself in the middle of this. You have 2 dlsw devices (router and/or cat6k switch). They establish a tcp pipe between each other and are configured to listen for llc2 frames on the lan side interfaces. The dlsw peers basically pick up the llc2 packet, encaps in tcp, transport to the otherside, decapsulate and put out again as llc2. The end stations are not aware that dlsw is in the middle. Going back to the phases of llc2 connection above, dlsw handles the test phase via reachability, XID is circuit setup and after sabme/ua we have a dlsw circuit. If you have issues setting this, open a tac case and I can help you through it. Matthew

[xavier.delcour]

Matthew, thanks a lot for all this information, I am sure it will help me a lot in order to be able to find a solution. As soon as I have a moment to try it I will perform a lab for it and will post my results.

Thanks for the tac support proposal, I should have access in the following days so if this issue still resist me I will contact you.

Regards,

Xavier

[Leo Laohoo]

I haven't dealt with DLSW since 2005 when I was with SITA/Equant.  Our client using this was Qantas and we had Cisco 2610 connected to their IBM mainframe.

Very easy to troubleshoot, though.

[xavier.delcour]

leolaohoo, it is true it does not seems so complicated but as always I have to find more time now to perform a small lab in order to materialize a little all the theory I read.

Regards,