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TCP/IP Tutorial and Technical Overview - IBM Redbooks

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► Stream Control Transmission Protocol (SCTP) provides a transport<br />

mechanism between S<strong>IP</strong> entities that exchange a large number of messages.<br />

Because S<strong>IP</strong> is transport-independent, support of SCTP is a relatively<br />

straightforward process, nearly identical to support for <strong>TCP</strong>. SCTP<br />

specifications are in RFC 3286.<br />

► Resource Reservation Protocol (RSVP) is defined in RFC 2205, <strong>and</strong> is used<br />

to create quality of service. The request is processed by each node along the<br />

session path <strong>and</strong> devices reserve the appropriate resources to support the<br />

application data stream.<br />

► Session Description Protocol (SDP) is a protocol that is defined in RFC 2327.<br />

It provides session announcements <strong>and</strong> session invitations in a multimedia<br />

environment. This enables the recipients of the session announcement to<br />

participate in the session.<br />

► Session Announcement Protocol (SAP) is another protocol for advertising<br />

multicast conferences <strong>and</strong> sessions <strong>and</strong> is defined by RFC 2974. It<br />

announces the existence of long-lived, wide-area, multicast sessions.<br />

20.3 Media Gateway Control Protocol (MGCP)<br />

MGCP is the Internet Engineering Task Force's st<strong>and</strong>ard for multimedia<br />

conferencing over <strong>IP</strong>. Development of the architectures that form MGCP started<br />

in mid-1998, but the Internet Engineering Task Force (IETF) published the latest<br />

MGCP st<strong>and</strong>ard, RFC 3435, in 2003.<br />

Unlike the S<strong>IP</strong> architecture, in which the intelligence resides in the endpoints, the<br />

MGCP model assumes that the core contains the faculties for implementing<br />

enhanced services. As a result, MGCP endpoint phones have minimal technical<br />

features. This aspect is beneficial for carriers because it enables the delivery of<br />

enhanced services through low-cost endpoints.<br />

MGCP provides the capabilities to:<br />

1. Determine the location of the target endpoint.<br />

2. Determine the media capabilities of the target endpoint through the Session<br />

Description Protocol (SDP).<br />

3. Determine the availability of the target endpoint.<br />

4. Establish a session between the originating <strong>and</strong> target endpoint.<br />

736 <strong>TCP</strong>/<strong>IP</strong> <strong>Tutorial</strong> <strong>and</strong> <strong>Technical</strong> <strong>Overview</strong>

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