Network Working Group                                         Jon Postel
Request for Comments 717                                         SRI-ARC
NIC 35873                                                    1 July 1976

                        Assigned Network Numbers
	
This note specifies the numbers assigned to identify networks for use in
the inter-network protocol experiments.  Additional Numbers are assigned
by Jon Postel [POSTEL@ISIC or (415) 326-6200 x3718].

Assigned Network Numbers

  Name          Decimal     Octal

  ----------    -------     -----

  BBNRCCnet        3           3
  SanFranPRnet     7           7
  ARPANET         10          12
  BostonPRnet     11          13

Internetwork Header Format

  For convenience the current Internetwork protocol header and TCP
  headers are reproduced here:

  Octet Bit     Use                      (Width)

    --- Beginning of protocol-independent information ---

    0           Destination net          (8)
    1-3         Destination host         (24)
    4           Source net               (8)
    5-7         Source host              (24)
    8-9         Data length in octets    (16)
    10          Header length in octets  (8)
    11   0-3    Format                   (4)
      This field selects the appropriate gateway processing and is used
      to dispatch the packet to the appropriate protocol module in the  
      destination.  The following values are defined for this field:
        0 -- Escape; protocol is specified by a subsequent field
        1 -- TCP
        2 -- Secure TCP
        3-16 -- Not allocated
        17 -- Cross internet debugging

   --- End of protocol-independent information

   --- Beginning of TCP specific information ---

   11   4-7     Protocol version         (4)
   12-15        Sequence number          (32)
   16-17        Window                   (16)
   18-20        Control (as before)      (24)
   21-23        Destination port         (24)
   24           Packet label for debugging(8)
   25-27        Source port              (24)
   28-31        Acknowledgement number   (32)
   32-33        Checksum                 (16)
   34-          Data                     

   --- End of TCP specific information ---

   --- Beginning of short TCP specific information ---

   11   4-7     Protocol Version         (4)
   12-25        Sequence number          (32)
   16           Destination KID          (8)
   17           Source KID               (8)
   18-19        Control (no special function field)(16)
   20-          Data

   --- End of short TCP specific information ---