openh323gk-developer

[Openh323gk-developer] Interoperability Issues

[Pablo S. <pe...@co...>]

Hi there,
            I have been trying the GNUGK Proxy extensively the past days. 
Hacking the code, I was able to establish a phone call from an unregistered 
Endpoint to a GW that is inside another GK's zone. That way, my proxy works 
only as a proxy (GW) and does not work as a GK.
Check out the graph:

  GK										    GK
Zone 1									Zone 2
    |										      |
Planet IP-Phone  <------> GNUGK "Hacked" Proxy <-----> MAX TNT GW

That way it worked ok for both fast start and non fast start procedures.

After that I tried replacing the Planet IP-Phone with a Cisco GW. That is when 
I had the following problem:
After the MAX TNT GW receives the "facility TerminalCapabilitySet" message, it 
responds with an "empty TerminalCapabilitySet" and after that sends a 
"ReleaseComplete" message, with ternination cause value == 42 (Switching 
Equipment Congestion).

Find attached the messages flows for the 2 cases mentioned above.
One thing that catched my attention was that for the IP-Phone, the first 
"OpenLogicalChannel" message is sent by the MAX TNT Gw.
And for the other case, the Cisco GW is the first one to send an 
"OpenLogicalChannel" message.

I am not an expert in the H323 protocol. So, if anyone could give me an idea 
of what is going on here, I would really appreciate your help.

                thanks in advance,
                                            Pablo Salinas

[Openh323gk-developer] Interoperability Issues

[Pablo S. <pe...@co...>]

Hi there,
            I have been trying the GNUGK Proxy extensively the past days. 
Hacking the code, I was able to establish a phone call from an unregistered 
Endpoint to a GW that is inside another GK's zone. That way, my proxy works 
only as a proxy (GW) and does not work as a GK.
Check out the graph:

Planet IP-Phone  <------> GNUGK "Hacked" Proxy <-----> MAX TNT GW

That way it worked ok for both fast start and non fast start procedures.

After that I tried replacing the Planet IP-Phone with a Cisco GW. That is when 
I had the following problem:
After the MAX TNT GW receives the "facility TerminalCapabilitySet" message, it 
responds with an "empty TerminalCapabilitySet" and after that sends a 
"ReleaseComplete" message, with ternination cause value == 42 (Switching 
Equipment Congestion).

Find attached the messages flows for the 2 cases mentioned above.
One thing that catched my attention was that for the IP-Phone, the first 
"OpenLogicalChannel" message is sent by the MAX TNT Gw.
And for the other case, the Cisco GW is the first one to send an 
"OpenLogicalChannel" message.

I am not an expert in the H323 protocol. So, if anyone could give me an idea 
of what is going on here, I would really appreciate your help.

                thanks in advance,
                                            Pablo Salinas