H323 Stack

by | Mar 4, 2010 | H.323, IOS, Lab, Non classé, Written Theory | 0 comments

We have already spoken about Gatekeeper signaling in this previous post but let’ be more general and see what are the common elements of H.323 stack.

We have H225 RAS ( Registration Admission and Status) which is used between the GK and H323 endpoints.

But under normal operation , we have also H225 which is the call control and signaling part of the H323 stack. So we use it to establish connections.

We have also H245 which is the negotiation part of the H323 stack. So it is during this stage that you can exchange capabilities/codecs, establish logical channels. It is in fact all settings for the transmission of the media.

Reminder:

  • H225 RAS  => UDP/1719
  • GK Discovery => UDP/1718

The Multicast GK discovery uses IP Address 224.0.1.41