RFC 717

RFC 717: Assigned Network Numbers 💖✨

okay so this is the title block, bestie 🎀 Network Working Group, Request for Comments 717, NIC 35873, written by Jon Postel (SRI-ARC), dated 1 July 1976 🦋 The original page headers read:

NWG/RFC# 717                         JBP  30-JUN-76 16:58  35873
Assigned Network Numbers

ngl, the original doesn't name a category or status, and it doesn't say what it obsoletes or updates. so I'm not making any of that up 🙈

Assigned Network Numbers 🌸

this note is where the numbers get assigned to identify networks for the inter-network protocol experiments 🧚 more numbers get handed out by Jon Postel, and you can reach him at [POSTEL@ISIC or (415) 326-6200 x3718] 📞

Assigned Network Numbers 💅

here's the list, no cap 💅

  Name        Decimal     Octal

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

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

Internetwork Header Format 🍓

so for convenience, the current Internetwork protocol header and TCP headers are copied right here so you don't have to go digging 🫶

Protocol-independent information 🌈

  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)

the Format field is the main character here 👑 it picks the right gateway processing and sends the packet to the matching protocol module at the destination. these are the values defined for it:

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 ---

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NWG/RFC# 717 JBP 30-JUN-76 16:58 35873 Assigned Network Numbers

TCP specific 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 ---

Short 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 ---

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