RTP port numbers have changed

Posts: 37 · Vonage Forum Junior Joined: Nov 16, 2005 Posts: 37

Hi everyone,

Since I got Vonage about a year ago I followed the UDP port range guidelines specified in the following document:
http://vonage.com/help.php?article=1098&category=44&nav=3

Here Vonage clearly states that they use UDP ports 10,000 through 20,000. It seems that this has changed and the document was never updated. More specifically I was working on my firewall (on my Cisco 871) and I was monitoring the ports in use when I made a call out. Frequently the RTP port numbers opened from Vonage were port 22,000 or higher. My adapter, an RTP300, consistently opened an RTP port 10,100 or lower.

This normally wouldn't be a big deal, however it makes a difference in how I handle QoS for Vonage. Previously I was matching on RTP packets in the Vonage port range, 10000 to 20000. With this new range some of my calls were not getting the proper QoS treatment. Thankfully the RTP300 marks its traffic with the proper (if old) DSCP values. Specifically:

RTP traffic is marked DSCP ef (or 46 if you know the decimal values)

SIP control traffic is marked DSCP af31 (or 26 if you know the decimal values)

I'm now handling QoS based on these values instead of the port range.

Just a heads up for those who are doing anything in your network based on the ports Vonage has posted on their website.

Posts: 533 · Posted: Mon Nov 27, 2006 10:25 am Post subject:

Thanks for the info Celeron.

If you're using an IOS device (12.2.8T or higher) for QoS, you can use:

match protocol rtp audio

in your class-map and you don't have to worry about matching the correct port range or dscp values.

Posts: 37 · Vonage Forum Junior Joined: Nov 16, 2005 Posts: 37

EzCo wrote:

Thanks for the info Celeron.

If you're using an IOS device (12.2.8T or higher) for QoS, you can use:

match protocol rtp audio

in your class-map and you don't have to worry about matching the correct port range or dscp values.

Actually this command is not available in 12.4(6)T IOS and higher. I'm not sure why it was removed but it is no longer present.

I happen to be running 12.4(9)T2 at the moment on my 871.

Posts: 533 · Posted: Mon Nov 27, 2006 3:19 pm Post subject:

Celeron wrote:

EzCo wrote:

Thanks for the info Celeron.

If you're using an IOS device (12.2.8T or higher) for QoS, you can use:

match protocol rtp audio

in your class-map and you don't have to worry about matching the correct port range or dscp values.

Actually this command is not available in 12.4(6)T IOS and higher. I'm not sure why it was removed but it is no longer present.

I happen to be running 12.4(9)T2 at the moment on my 871.

On that platform, make sure you're running the Advanced IP Services feature set. That command uses nBAR for the protocol classification, which is only available in that feature set for the 871.

Posts: 37 · Vonage Forum Junior Joined: Nov 16, 2005 Posts: 37

EzCo wrote:

On that platform, make sure you're running the Advanced IP Services feature set. That command uses nBAR for the protocol classification, which is only available in that feature set for the 871.

Indeed, I am running Advanced IP Services. The command is there no longer. I was using in12.4(4)T. Changed nothingin the config when I upgraded to 12.4(6)T and it disappeared.

Posts: 533 · Posted: Mon Nov 27, 2006 9:10 pm Post subject:

Celeron wrote:

Indeed, I am running Advanced IP Services. The command is there no longer. I was using in12.4(4)T. Changed nothingin the config when I upgraded to 12.4(6)T and it disappeared.

That's really strange. I have a 1711 running 12.4.9T1 and it's there. Albeit the 1711 supports more features in lower feature sets.