Inbound and Outbound FastStart in CUCM H.323 GW

[JustForVoice_2]

Hello,

I need to know if some one can list when I have to enable

Inbound and Outbound FastStart in H.323 GW.

[JustForVoice_2]

In some cases I need it with CUBE.

I am trying to know why, but still I did not find why.

If some one know why? or he knows other cases we need to enable Inbound or Outbound FastStart, please share it.

[Chris Deren]

Why are you using H323 with CUBE?  Normally you would use SIP in which case the question is about Early Offer vs. Delayed Offer, kind of similar to H323 fast start concept.  Without going too much details as you can google these terms and get very detailed explanations, the difference is when the media starts flowing between IP addresses, is it as part of the initial INVITE with SDP or later. Most carriers use Early Offer and that is what CUBE should do, CUCM is typically Delayed Offer where enabling PRACK is recommended to avoid ghost calls to some PSTN destinations that use IVR.

HTH,

Chris

[JustForVoice_2]

Thank you fro your reply and +5.

The purpose of my question is to study some cases. so I can understand more.

When I tried some debugs, I did not find any changes between enable and disable faststart.

I think CUCM can only use slowstart. So that I need to know what is the effect from enabling faststart.