RFC 3481 (rfc3481) - Page 2 of 26

TCP over Second (2

RFC 3481                    TCP over 2.5G/3G               February 2003


Table of Contents

   1.  Introduction. . . . . . . . . . . . . . . . . . . . . . . . .   3
   2.  2.5G and 3G Link Characteristics. . . . . . . . . . . . . . .   4
       2.1  Latency. . . . . . . . . . . . . . . . . . . . . . . . .   4
       2.2  Data Rates . . . . . . . . . . . . . . . . . . . . . . .   5
       2.3  Asymmetry  . . . . . . . . . . . . . . . . . . . . . . .   6
       2.4  Delay Spikes . . . . . . . . . . . . . . . . . . . . . .   6
       2.5  Packet Loss Due to Corruption. . . . . . . . . . . . . .   7
       2.6  Intersystem Handovers. . . . . . . . . . . . . . . . . .   7
       2.7  Bandwidth Oscillation. . . . . . . . . . . . . . . . . .   7
   3.  Example 2.5G and 3G Deployments . . . . . . . . . . . . . . .   8
       3.1  2.5G Technologies: GPRS, HSCSD and CDMA2000 1XRTT. . . .   8
       3.2  A 3G Technology: W-CDMA. . . . . . . . . . . . . . . . .   8
       3.3  A 3G Technology: CDMA2000 1X-EV. . . . . . . . . . . . .  10
   4.  TCP over 2.5G and 3G. . . . . . . . . . . . . . . . . . . . .  10
       4.1  Appropriate Window Size (Sender & Receiver). . . . . . .  11
       4.2  Increased Initial Window (Sender). . . . . . . . . . . .  11
       4.3  Limited Transmit (Sender). . . . . . . . . . . . . . . .  12
       4.4  IP MTU Larger than Default . . . . . . . . . . . . . . .  12
       4.5  Path MTU Discovery (Sender & Intermediate Routers) . . .  13
       4.6  Selective Acknowledgments (Sender & Receiver). . . . . .  13
       4.7  Explicit Congestion Notification (Sender, Receiver &
            Intermediate Routers). . . . . . . . . . . . . . . . . .  13
       4.8  TCP Timestamps Option (Sender & Receiver). . . . . . . .  13
       4.9  Disabling RFC 1144 TCP/IP Header Compression (Wireless
            Host)   . . . . . . . . . . . . . . . . . . . . . . . . . 15
       4.10 Summary . . . . . . . . . . . . . . . . . . . . . . . . . 16
   5.  Open Issues  . . . . . . . . . . . . . . . . . . . . . . . . . 16
   6.  Security Considerations  . . . . . . . . . . . . . . . . . . . 18
   7.  IANA Considerations  . . . . . . . . . . . . . . . . . . . . . 18
   8.  Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 19
   9.  Normative References . . . . . . . . . . . . . . . . . . . . . 19
   10. Informative References . . . . . . . . . . . . . . . . . . . . 21
   11. Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 25
   12. Full Copyright Statement . . . . . . . . . . . . . . . . . . . 26















Inamura, et al.          Best Current Practice