mgcp

CCIE Voice / CCVP Exam Objectives #7: RTP and cRTP

Mark_Lewis — Wed, 02 Jul 2008 12:47:16 -0400

While protocols like MGCP, SIP, H.323 (H.225/H.225 RAS/H.245), and SCCP provide signalling in VoIP/IP telephony/unified communications networks, the Real Time Transport Protocol (RTP) is used to transport the voice and video media packets.

RTP has a number of important characteristics, including the following:

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CCIE Voice / CCVP Exam Objectives #5: H323 Messages (Cont.)

Mark_Lewis — Mon, 26 May 2008 09:32:06 -0400

In my previous blog post, I described the most important H.323 protocols, standards, and network elements. This time I'll be taking a look at how those network elements communicate.

As mentioned last time, H.225 RAS allows communication between endpoints and gatekeepers, using UDP ports 1718 and 1719. There are a number of different H.225 RAS messages, including:

Gatekeeper discovery (Gatekeeper Request [GRQ], Gatekeeper Confirm [GCF], and Gatekeeper Reject [GRJ]): used by endpoints to discover gatekeepers with which to register.

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CCIE Voice / CCVP Exam Objectives #4: H.323

Mark_Lewis — Mon, 19 May 2008 05:31:10 -0400

So far in this series I have described two telephony protocols (SIP and MGCP) that feature prominently on the CCIE Voice and CCVP exam blueprints. In this blog entry, I am going to describe another, H.323.

H.323 is a collection or framework of ITU standards for interactive multimedia communications over a packet network. Not only does it appear in a large proportion of Cisco's IP telephony/voice related exams, but there is also a huge installed base of H.323 enabled devices out in the field - so, whether you are focused on passing exams or doing a great job (hopefully both!), you're going to need to have a good understanding of it.

Some of the most important protocols and standards that make up the H.323 framework are:

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CCIE Voice/CCVP Objectives #3: Media Gateway Control Protocol (MGCP)

Mark_Lewis — Mon, 12 May 2008 05:44:33 -0400

A telephony protocol that features prominently in the CCIE Voice and CCVP exam blueprints (as well as the real world!) is the Media Gateway Control Protocol (MGCP). MGCP is a master-slave protocol that involves a Media Gateway Controller (MGC, the master) and Media Gateways (MGs, the slaves).

MGCP is often used in Cisco Unified Communications Manager / CallManager (UCM/CCM) networks, with UCM/CCMs functioning as the MGCs that control voice gateways (MGs).

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