RFC 2147 (rfc2147) - Page 3 of 3

TCP and UDP over IPv6 Jumbograms

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RFC 2147            TCP and UDP over IPv6 Jumbograms            May 1997


   Urgent field is set to 65535 to indicate that the Urgent Pointer is
   beyond the end of this packet.  The second piece can then be sent
   with the Urgent field set normally.

      Note: The first piece does not have to include all of the data up
      to the Urgent Pointer.  It can be shorter, just as long as it ends
      within 65534 bytes of the Urgent Pointer, so that the offset to
      the Urgent Pointer in the second piece will be less than 65535
      bytes.

   For TCP input processing, when a TCP packet is received with the URG
   bit set and an Urgent field of 65535, the Urgent Pointer is
   calculated using an offset equal to the length of the TCP data,
   rather than the offset in the Urgent field.

   It should also be noted that though the TCP window is only 16-bits,
   larger windows can be used through use of the TCP Window Scale option
   [Jacobson92].

4.  Security Considerations

   There are no known security issues involved in these changes.

5.  References

   [Jacobson92] Jacobson, V., R. Braden and D. Borman, "TCP Extensions
   for High Performance", RFC 1323, LBL, ISI and Cray Research, May
   1992.

   [Deering95] Deering, S. and R. Hinden, "Internet Protocol, Version 6
   (IPv6) Specification", RFC 1883, Xerox PARC and Ipsilon Networks,
   December 1995.

Author's Address

   David A. Borman
   Berkeley Software Design, Inc.
   4719 Weston Hills Drive
   Eagan, MN 55123
   Phone: (612) 405-8194
   Mailing List: 
   Email: 









Borman                      Standards Track
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