TB MXP NAT issue with Cisco 1841

[Joe Vallender]

We have a customer with MXP 3000's F5.3 being NAT'ed by Cisco 1841 routers (c1841-spservicesk9-mz.123-14.YT1.bin) successfully. We had to disable several of the audio protocols in the MXP's to reduce the h.323 packet size and keep them from being fragmented during cap exchange and running into Cisco Bug CSCse38786.

One of the sites had their MXP replaced and upgraded to F6.2. We cannot get the Cisco 1841 to NAT properly during the capability exchange and it looks like the fragmented packet bug.

Has anybody run into this and if so, how did you get around it? I've disabled the same audio protocols in the MXP as before but it appears that there are many more capabilities being advertised causing fragmentation and NAT failure. At this point we are requesting a downgrade to get the MXP back in service.

[Glen Sykes]

I've not had this identical problem, but when using the H.323 NAT process within a Cisco router, I've had to downgrade my endpoint on many occasions. The usual problem, particularly with Tandberg MXP's is the Cisco can't parse the H.225 / H.245 messages properly and the calls break.

On Tandberg F6 in particular, I've found the references to H.241 extended capabilities has caused problems, and the only way round this is to downgrade the endpoint.