RFC 1042 (rfc1042) - Page 2 of 15

Standard for the transmission of IP datagrams over IEEE 802 networks

Alternative Format: Original Text Document


RFC 1042            IP and ARP on IEEE 802 Networks        February 1988


   allowing for interoperability at the Data Link Layer.

   It is the goal of this memo to specify enough about the use of IP and
   ARP on each type of network to ensure that:

      (1) all equipment using IP or ARP on 802.3 networks will
      interoperate,

      (2) all equipment using IP or ARP on 802.4 networks will
      interoperate,

      (3) all equipment using IP or ARP on 802.5 networks will
      interoperate.

   Of course, the goal of IP is interoperability between computers
   attached to different networks, when those networks are
   interconnected via an IP gateway [8].  The use of IEEE 802.1
   compatible Transparent Bridges to allow interoperability across
   different networks is not fully described pending completion of that
   standard.

Description

   IEEE 802 networks may be used as IP networks of any class (A, B, or
   C).  These systems use two Link Service Access Point (LSAP) fields of
   the LLC header in much the same way the ARPANET uses the "link"
   field.  Further, there is an extension of the LLC header called the
   Sub-Network Access Protocol (SNAP).

   IP datagrams are sent on IEEE 802 networks encapsulated within the
   802.2 LLC and SNAP data link layers, and the 802.3, 802.4, or 802.5
   physical networks layers.  The SNAP is used with an Organization Code
   indicating that the following 16 bits specify the EtherType code (as
   listed in Assigned Numbers [7]).

   Normally, all communication is performed using 802.2 type 1
   communication.  Consenting systems on the same IEEE 802 network may
   use 802.2 type 2 communication after verifying that it is supported
   by both nodes.  This is accomplished using the 802.2 XID mechanism.
   However, type 1 communication is the recommended method at this time
   and must be supported by all implementations.  The rest of this
   specification assumes the use of type 1 communication.

   The IEEE 802 networks may have 16-bit or 48-bit physical addresses.
   This specification allows the use of either size of address within a
   given IEEE 802 network.

   Note that the 802.3 standard specifies a transmission rate of from 1



Postel & Reynolds

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