Network Working Group P. Blatherwick (Editor)
Request for Comments: 3054 Nortel Networks
Category: Informational R. Bell
(Chair TIA TR-41.3.4)
Megaco IP Phone Media Gateway Application Profile
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright (C) The Internet Society (2001). All Rights Reserved.
This document specifies a particular application of the Megaco/H.248
Protocol for control of Internet telephones and similar appliances:
the Megaco IP Phone Media Gateway. The telephone itself is a Media
Gateway (MG), controlled by the Megaco/H.248 Protocol, with
application control intelligence located in the Media Gateway
Controller (MGC). To achieve a high degree of interoperability and
design efficiency in such end-user devices, a consistent
architectural approach, a particular organization of Terminations and
Packages, and a Protocol Profile are described. The approach makes
use of existing Protocol features and user interface related
Packages, and is thus a straight-forward application of the
This document represents the current view from the TIA working group
on VoIP (Voice over IP) telephone specification , TIA TR-41.3.4,
with the intent of using this as part of its "whole device"
specification as an optional method of device control.
Industry feedback has made it clear that interoperability and
acoustic performance of Internet telephones is key to the rapid and
extensive commercialization of these products. To facilitate this,
the TIA has established working group TR-41.3.4 to develop a standard
Blatherwick, et al. Informational [Page 1]RFC 3054 Megaco IP Phone Media GW Application Profile January 2001
for VoIP telephones. The TR-41.3.4 working group has included the
"whole device" within the scope of the standard, so a full range of
requirements including acoustic performance, protocols, methods for
powering and safety are provided. Where possible, the requirements
are based on existing standards, which are included by reference.
The TIA TR-41.3.4 working group has also recognized that its proposed
standard must enable creative application of the equipment, encourage
the development of new capabilities and allow for high levels of
product customization. To achieve this, peer to peer architectures
that are based on protocols such as H.323 or SIP and master/slave
architectures such as Megaco/H.248 Protocol are both necessary and
In support of the Megaco/H.248 Protocol development effort, the TR-
41.3.4 working group has considered product enabling issues and
requirements, and has developed an approach to use the Megaco/H.248
Protocol for Internet telephone device control. This document
represents the working group's current view.
This document covers the general requirements of the Megaco IP Phone
application (section 3), architectural approach and MG organization
(section 4), details of specific Termination types used and Packages
supported by each (section 5), and the Megaco IP Phone Protocol
Profile (section 6).
The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
document, are to be interpreted as described in RFC 2119 .
3. General Requirements
The following general requirements were identified to drive the
Megaco IP Phone design :
1. The Megaco IP Phone must meet the basic needs of the business user
from day one;
2. Provide a path for rapid expansion to support sophisticated
business telephony features;
3. Flexibility to allow for a very wide range of telephones and
similar devices to be defined, from very simple to very feature
4. Simple, minimal design;
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5. Allow device cost to be appropriate to capabilities provided;