A Scalable Port Forwarding for P2P-Based Wi-Fi Applications

  • Ming-Wei Wu
  • Yennun Huang
  • Ing-Yi Chen
  • Shyue-Kung Lu
  • Sy-Yen Kuo
Conference paper
Part of the Lecture Notes in Computer Science book series (LNCS, volume 4138)


A few killer applications that rocked the Internet community these years are peer-to-peer (P2P) file-sharing applications and VoIP (voice over Internet Protocol) telephony services. Unlike traditional client-and-server applications in which servers are services provider and by default should be public addressable, each peer in P2P networks can play both roles (client and server). However, legacy usage of the network address translation (NAT) module on most wireless access points (APs) causes new problems with emerging P2P communications especially in opposing APs (both peers of an Internet connection are behind AP) where each peer uses private Internet Protocol (IP) address and neither side has global visibility to each other. This article therefore examines such issue from three approaches, 1) leveraging the complexity of client application, 2) introducing additional intermediate gateways and protocols and 3) enhancing the wireless AP itself. Client-based solutions such as UDP/TCP hole-punching suffer from race condition while gateway-based solutions tend to incur overhead for interoperability and deployment. This paper proposes a scalable port forwarding (SPF) design for wireless AP, which introduces little or negligible time and space complexity, to significantly improve the connectivity and scalability of a conventional AP by 1) lessening the race condition of P2P traversals in opposing APs, 2) multiplexing the port numbers to exceed theoretical upper bound 65,535 and 3) allowing more servers to bind to a specific port.


Wi-Fi Access Point (AP) Peer-to-Peer (P2P) Port Forwarding Network Address Translation (NAT) 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. 1.
    Touch, J.D.: Those pesky NATs. IEEE Internet Computing 6(4), 96 (2002)CrossRefGoogle Scholar
  2. 2.
    Shieh, S.-P., Ho, F.-S., et al.: Network address translators: effects on security protocols and applications in the TCP/IP stack. IEEE Internet Computing 4(6), 42–49 (2000)CrossRefGoogle Scholar
  3. 3.
    Bidirectional peer-to-peer communication with interposing firewalls and NATs, Peer-to-peer working group (August 2001)Google Scholar
  4. 4.
    Gong, L.: JXTA: a network programming environment. IEEE Internet Computing 5(3), 88–95 (2001)CrossRefGoogle Scholar
  5. 5.
    Miller, B.A., Nixon, T.: Home networking with Universal Plug and Play. IEEE Communications Magazine 39(12), 104–109 (2001)CrossRefGoogle Scholar
  6. 6.
    Rosenberg, J., Huitema, C., Mahy, R., Weinberger, J.: STUN - Simple Traversal of UDP Through Network Address Translators, draft-ietf-midcom-stun-05 (work in progress) (December 2002), Available at:
  7. 7.
    Rosenberg, J., Weinberger, J., Mahy, R., Huitema, C.: Traversal Using Relay NAT (TURN), draft-rosenberg-midcom-turn-02 (work in progress) (October 2003), Available at:
  8. 8.
    Kegel, D.: NAT and peer-to-peer networking (July 1999), Available at:
  9. 9.
    Holdrege, M., Srisuresh, P.: Protocol complications with the IP network address translator, RFC 3027 (January 2001)Google Scholar
  10. 10.
    Huitema., C.: Teredo: Tunneling IPv6 over UDP through NATs (June 2004), Internet-Draft available at:
  11. 11.
    Rosenberg, J.: Interactive connectivity establishment (ICE) (October 2003), Internet-Draft available at:
  12. 12.
    Eppinger., J. L.: TCP connections for P2P apps: A software approach to solving the NAT problem, Technical Report CMU-ISRI-05-104, Carnegie Mellon University (January 2005) Google Scholar
  13. 13.
    Guha, S., Takeday, Y., Francis, P.: NUTSS: A SIP-based approach to UDP and TCP network connectivity. In: ACM SIGCOMM 2004 Workshops (August 2004)Google Scholar
  14. 14.
    Biggadike, A., Ferullo, D., Wilson, G., Perrig, A.: NATBLASTER: Establishing TCP connections between hosts behind NATs. In: ACM SIGCOMM Asia Workshop, Beijing, China (April 2005)Google Scholar
  15. 15.
    Baset, S.A., Schulzrinne, H.: An Analysis of the Skype Peer-to-Peer Internet Telephony Protocol. In: Proceedings of the INFOCOM (2006)Google Scholar
  16. 16.
    Saroiu, S., Gummadi, P.K., Gribble, S.D.: A Measurement Study of Peer-to-Peer File Sharing Systems. In: Proceedings of Multimedia Computing and Networking 2002 (MMCN 2002), San Jose, CA (January 2002)Google Scholar
  17. 17.
    Lin, Y.-D., Wei, H.-Y., Yu, S.-T.: Building an Integrated Security Gateway: Mechanisms, Performance Evaluation, Implementation, and Research Issues. IEEE Communication Surveys and Tutorials, third quarter 4(1) (2002)Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2006

Authors and Affiliations

  • Ming-Wei Wu
    • 1
  • Yennun Huang
    • 2
  • Ing-Yi Chen
    • 3
  • Shyue-Kung Lu
    • 4
  • Sy-Yen Kuo
    • 1
  1. 1.National Taiwan UniversityTaiwan
  2. 2.AT&T LabsFlorham ParkUSA
  3. 3.National Taipei University of TechnologyTaiwan
  4. 4.Fu Jen Catholic UniversityTaiwan

Personalised recommendations