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

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

MGCP ports

This question is drafted after reading a variety of different info on MGCP ports. I am looking for the actual ports used by MGCP whether it be UDP, TCP or a mix of both.

Based on RFC 2705,

http://www.faqs.org/rfcs/rfc2705.html

MGCP callagents use port 2427 (UDP)to talk to gateways. While gateways use port 2727 (UDP) to talk to Callagents. Does callmanager use port 2727 ? There is no mention about port 2727 in this link -

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00801a62b9.shtml

So what is the story on port 2727?

Looking at this link below, you can see that MGCP uses UDP port 2427 for Control traffic and TCP port 2428 for backhaul.

http://www.cisco.com/en/US/products/sw/voicesw/ps556/products_tech_note09186a00801a62b9.shtml

If you look at CM Help page, (screen shot attached) it says that MGCP Listen Port 2427 in Callmanager is a TCP port (not UDP). So is MGCP really using UDP or TCP ?

Also it mentions a Keepalive port, again uses TCP port number 2428. What is this port used for ? This does match with the backhaul port..

Configuration of MGCP gateway - In the configuration of MGCP gateway you specifiy the command "mgcp call-agent <ip add> <port> <blah>". To configure MGCP on a cisco router to work with Cisco callmanager you specify the port as 2427. This means that the router will talk to the callagent on port 2427. This conflicts with the ports specified in RFC 2705. RFC 2705 says that communication from callagent to gateways use port 2427.

Can any body clear the confusion here ?

Sankar.

1 ACCEPTED SOLUTION

Accepted Solutions
Blue

Re: MGCP ports

Shanky,

I have a Sniffer running on a MGCP gateway with an active PRI as well as analog ports. There is a single TCP connection on port 2428 to the subscriber, as well as UDP on port 2427.

So yes just a single TCP connection for both.

Dave

4 REPLIES

Re: MGCP ports

Here is what I got after an ethereal sniff as well as netstat output on CM.

* A netstat command on the CM shows TCP port 2428 to be open. No other TCP ports for MGCP (no 2427)

* Ethereal shows all MGCP commands (NTFY, RSIP, CRCX etc) transported over UDP port 2427 (source and destination)

* Ethereal also shows MGCP keepalives every 15 seconds on TCP port 2428.

* According to the sh ccm-manager output I can see that Backhaul port is TCP port 2428. So is the same TCP port 2428 used for keepalives as well as q931 backhaul ??

Sankar.

PS: Cisco Callmanager doesnt seem to follow the ports defined in RFC 2705.

Blue

Re: MGCP ports

Shanky,

I have a Sniffer running on a MGCP gateway with an active PRI as well as analog ports. There is a single TCP connection on port 2428 to the subscriber, as well as UDP on port 2427.

So yes just a single TCP connection for both.

Dave

Re: MGCP ports

Dave,

Thanks for your input. Is it also possible for you to upload the ethereal trace.

Thanks

Sankar.

Blue

Re: MGCP ports

I am using a Network General Sniffer, so I saved the traces as text files, one for UDP and the other TCP.

Dave

6535
Views
0
Helpful
4
Replies