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H323 calls behind PAT - one way voice

Hi,

I'm receiving calls to an AS5350 from h323 gateway with a public IP and phones connected to it with local IP's. The calls are authenticated in Cisco AS by the public IP of the GW, but then cisco is seeing the private IP of the phone and is sending the rtp packets to that IP - result one way voice.

With the command "sh call active voice brief" i see the call connected and the private IP.

Any idea how to fix this?

Thanks.

Robert

6 REPLIES

Re: H323 calls behind PAT - one way voice

If your gateway can support the load and image try using a H323 proxy. You need an image supporting proxy or MCM features. The proxy terminates the RTP Streams of the devices that are configured to use it.

Here is a sample config.

proxy h323

loopback 1

ip address x.x.x.x x.x.x.x

h323 interface

h323 h323-id proxy

h323 gatekeeper id domain-name ipaddr x.x.x.x

gatekeeper

use-proxy domain-name remote-zone remote-domain-name outbound-from gateway

!above is one line

Let me know if this helps

Thanks

Fred

(Please rate the posts)

Re: H323 calls behind PAT - one way voice

Robert,

Looks like the H323 Proxy feature was rolled into the Cisco Multiservice Ip-to-Ip gateway. Based off what I read it does the proxy by default when this is configured. Check this out and see if this might help as well

http://www.cisco.com/en/US/products/sw/voicesw/ps5640/products_configuration_guide_chapter09186a00803fecdc.html

Thanks

Fred

(Please rate the posts)

New Member

Re: H323 calls behind PAT - one way voice

How is working with a h323 proxy ?

The calls are sent to a gatekeeper, will go to the h323 proxy, and I will see the IP of the loopback interface ?

The h323 proxy will not send the call back to the private IP, like the cisco is doing it now ?

This config will not interfere with the other h323 calls which are running now ?

Re: H323 calls behind PAT - one way voice

I haven't used the proxy feature in production. I have used the Ip-to-Ip gateway with CMEs to CallManager cluster. Didn't know it had replaced the H323 proxy feature when I first posted until I did more research.

The H323 GW should be configured either with the IP-to-IP gateway feature or the legacy H323 proxy (requires GK image as well I believe). When you configure the gateway it will then terminate all the calls to the gateway that H323. The gateway will still talk to the IP Phones via their private address but your AS5350 will see the loopback address of the proxy as the media endpoint.

In my typical scenario all calls were proxied. You could probably configure it otherwise or use a separate gateway. Also I'm assuming you have access to the H323 gw you reference. If you don't you could add a GK and route to it to do the same function.

Thanks

Fred

(Please rate the posts)

New Member

Re: H323 calls behind PAT - one way voice

My scenario is like this:

There is a H323 GW with phones behind. I don't know the brand of the GW, but is configurable via a simple web interface, not many things to configure.

The H323 GW is sending the calls to AS5350.

The question is if there is a way to force the AS5350 to use the public IP and different ports of the H323 GW for the RTP stream, and not the local IP's of the phones behind the H323GW.

The config should not interfere with other sip and h323 calls coming to the Cisco.

Re: H323 calls behind PAT - one way voice

If the calls are terminating to the AS5350, then no. The 3rd party H323 gateway might have a proxy option but frankly I don't know because it's not a Cisco GW.

Now you could put a GK in front of the Gateway, configure it with proxy or Ip-to-IP GW, default route to the 3rd party gw, enable dynamic routing for your inside to the AS5350 and finally setup H323 trunks between the 3rd party GW and your AS5350. Without seeing things in complete detail this should high-level work for you.

Thanks

Fred

(Please rate the posts)

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