Open Access

NAT Traversing Solutions for SIP Applications

EURASIP Journal on Wireless Communications and Networking20082008:639528

Received: 2 January 2008

Accepted: 2 March 2008

Published: 31 March 2008


Session Initiation Protocol (SIP) has been proposed for multimedia services and wide-area connectivity in smart home environments (SHEs). An important issue for SIP deployment in SHEs is network address translator (NAT) traversing. SIP and Real-time Transport Protocol (RTP) packets are delivered between an SHE (i.e., private IP network) and Internet (i.e., a public IP network) through an NAT function of a home gateway, and the NAT translates the IP/transport layer address and port number but leaves the application layer content unchanged. This results in inconsistency between the IP addresses/port numbers in the IP/transport layers and those in the SIP layer. To resolve this issue, we describe six solutions including static route, UPnP, STUN, ICE, ALG, and SBC. Then we compare these solutions in terms of smart home appliance (SHA) modification, scope of NATs supported, multilayer NAT traversal, ease of configuration, security issue, and time complexities.

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Authors’ Affiliations

Institute of Computer Science and Information Engineering, National I-Lan University
Department of Computer Science, National Chiao Tung University
Department of Electronic Engineering, National I-Lan University
Department of Electrical Engineering, National Dong Hwa University


© Whai-En Chen et al. 2008

This article is published under license to BioMed Central Ltd. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.