Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
Community Member

ATA-186 x RTP - Weird Behavior!

I have implemented some QoS policies in my routers. Two of the measures are: RTP Header Compression (cRTP) and RTP priority (frame-relay ip rtp priority 16384 16383 256)

When I place calls using an ATA-186 (v. 2.13, H.323), I CAN'T see any change in the RTP statistics in the routers. It seems that the routers are NOT seeing any RTP packet to/from the ATA-186 (the remote gateway is another ATA too).

But, when I use the 1750 gateways (12.2.6c), the statistics on the routers are regularly updated, which means that the intermediate routers properly prioritize and compress RTP packets.

The statistics that I've been using are:

show ip rtp header-compression

show queuing interface serial 0/0

When I use the ATA to place the calls, the first command shows no increment in the number of sent or received compressed packets; the second shows no increment in the number of prioritized packets.

As the statistics behave as expected when the calls are placed by the 1750, I assume that the QoS configuration is ok.

The network topology is pretty simple:

ATA <-> 2620 <-> 2620 <-> ATA

1750 <-> 2620 <-> 2620 <-> 1750

Does anybody know what could be happening?

Thank you,



Re: ATA-186 x RTP - Weird Behavior!

Since there has been no response to your post, it appears to be either too complex or too rare an issue for other forum members to assist you. If you don't get a suitable response to your post, you may wish to review our resources at the online Technical Assistance Center ( or speak with a TAC engineer. You can open a TAC case online at

If anyone else in the forum has some advice, please reply to this thread.

Thank you for posting.

CreatePlease to create content