Problem Statement for SIP-signalled Peer-to-Peer Communication across Middleboxes

Document Type Expired Internet-Draft (individual)
Author Juergen Quittek 
Last updated 2006-03-01
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Middleboxes, particularly firewalls and network address translators, are essential components of today's Internet infrastructure. They are designed to support client-server applications well, but very often they are obstacles for peer-to-peer communication. This memo discusses middlebox traversal issues of SIP-based peer-to-peer communication. Required communication steps are analyzed concerning their potential constraints caused by middleboxes. The requirements derived from this analysis are compared with the capabilites of currently available middlebox traversal methods and SIP signaling standards. The comparison identifies open issues that need to be considered when designing standards for a SIP-based peer-to-peer communication infrastructure.


Juergen Quittek (

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