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].
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
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
