Subject: I-D ACTION:draft-sen-midcom-fw-nat-01.txt

From: [email-masked]
Date: Mon, 06 May 2002 07:25:18 -0400

A New Internet-Draft is available from the on-line Internet-Drafts directories.

	Title		: Midcom-unaware NAT/Firewall Traversal
	Author(s)	: S. Sen, P. Sollee, S. March
	Filename	: draft-sen-midcom-fw-nat-01.txt
	Pages		: 15
	Date		: 03-May-02
	
Bundled session applications such as FTP, H.323, SIP and RTSP, which 
use a signaling/control connection to establish a data/media flow, 
are usually broken, en-route, by Middleboxes such as NAT. Midcom 
proposes to solve this problem by allowing the Middlebox to be 
controlled through a generalized control interface by an 
application-aware entity called Midcom Agent. Since ubiquitous 
deployment of Midcom is still a few years away, an interim solution 
is needed to allow applications traverse NAT and Firewalls 
seamlessly without the help of embedded Application Layer Gateways 
(ALG). In this draft, a pre-Midcom solution framework is developed. 
A solution for the problem of NAT/FW traversal is needed both for 
the signaling and media/data paths. Two key components of the 
proposed solution are: (1) a Signaling Proxy server on the signaling 
path, and (2) a Media Proxy server on the media path. The Signaling 
server interacts with the Media server through a control interface. 
Although the primary applicability of this framework is shown for 
real-time RTP/UDP-based SIP multimedia sessions, these concepts 
should be generally applicable to other types of data sessions 
established through a control connection.

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