Standard for the transmission of 802.2 packets over IPX networks (RFC1132)
Original Publication Date: 1989-Nov-01
Included in the Prior Art Database: 2019-Feb-11
Internet Society Requests For Comment (RFCs)
This document specifies a standard method of encapsulating 802.2 packets on networks supporting Novell's Internet Packet Exchange Protocol (IPX). It obsoletes earlier documents detailing the transmission of Internet packets over IPX networks. It differs from these earlier documents in that it allows for the transmission of multiple network protocols over IPX and for the transmission of packets through IPX bridges.
Network Working Group L. McLaughlin III Request for Comments: 1132 The Wollongong Group November 1989
A Standard for the Transmission of 802.2 Packets over IPX Networks
Status of this Memo
This document specifies a standard method of encapsulating 802.2  packets on networks supporting Novell’s Internet Packet Exchange Protocol  (IPX). It obsoletes earlier documents detailing the transmission of Internet packets over IPX networks. It differs from these earlier documents in that it allows for the transmission of multiple network protocols over IPX and for the transmission of packets through IPX bridges. Distribution of this memo is unlimited.
The goal of this specification is to allow compatible and interoperable implementations for transmitting Internet packets such as the Internet Protocol  (IP) and Address Resolution Protocol  (ARP) as well as the Connectionless-mode Network Protocol  (CLNP) over IPX networks.
IPX is a proprietary standard developed by Novell derived from Xerox’s Internet Datagram Protocol  (IDP). Defining the encapsulation of the IEEE 802.2 Data Link Layer Standard over IPX in terms of yet another 802.X Physical Layer standard allows for the transmission of IP Datagrams as described in RFC 1042 . This document will focus on the implementation of that RFC over IPX networks.
In general, this specification allows IPX networks to be used to support any network protocol which can use the IEEE 802.2 Data Link Layer specification.
More specifically, IPX networks may be used to support IP networks and subnetworks of any class. By encapsulating IP datagrams within IPX datagrams and assigning IP numbers to the hosts on a IPX network, IP-based applications are supported on these hosts. The addition of an IP Gateway capable of encapsulating IP packets within 802.IPX datagrams would allow those hosts on an IPX network to communicate with the Internet.
McLaughlin [Page 1]
RFC 1132 802.2 Packets over IPX Networks November 1989
Maximum Transmission Unit
The maximum data size of a IPX datagram is 546 bytes. As the combined size of the 802.2 LLC and SNAP headers is 8 bytes, this results in a Maximum Transmission Unit (MTU) of 538 bytes.
The mapping of Internet Protocol addresses to 802.IPX addresses is done using the Address Resolution Protocol in the same fashion as with other IEEE 802.X physical addresses. However, the length of an 802.IPX physical address is 10 bytes rather than 2 or 6. This 10 byte physical address consists of the 4 bytes of the IPX network address followed by the 6 bytes of the IPX node address.
The byte transmission order is "big-endian" .
IPX packets may be broadcast by setting the IPX header Packet Type field to 0x14, the Destination Network field to the local network number, the the Destination Node field to 0xffffff, and the Immediate Address field of the IPX Event Control Block to 0xffffff.