Tunneling IPX traffic through IP networks
RFC 1234
Document | Type |
RFC - Historic
(June 1991; No errata)
Was draft-provan-ipxtunneling (individual)
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|
---|---|---|---|
Author | Don Provan | ||
Last updated | 2019-12-21 | ||
Stream | Legacy stream | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | Legacy state | (None) | |
Consensus Boilerplate | Unknown | ||
RFC Editor Note | (None) | ||
IESG | IESG state | RFC 1234 (Historic) | |
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group D. Provan Request for Comments: 1234 Novell, Inc. June 1991 Tunneling IPX Traffic through IP Networks Status of this Memo This memo describes a method of encapsulating IPX datagrams within UDP packets so that IPX traffic can travel across an IP internet. This RFC specifies an IAB standards track protocol for the Internet community, and requests discussion and suggestions for improvements. Please refer to the current edition of the "IAB Official Protocol Standards" for the standardization state and status of this protocol. Distribution of this memo is unlimited. Introduction Internet Packet eXchange protocol (IPX) is the internetwork protocol used by Novell's NetWare protocol suite. For the purposes of this paper, IPX is functionally equivalent to the Internet Datagram Protocol (IDP) from the Xerox Network Systems (XNS) protocol suite [1]. This memo describes a method of encapsulating IPX datagrams within UDP packets [2] so that IPX traffic can travel across an IP internet [3]. This RFC allows an IPX implementation to view an IP internet as a single IPX network. An implementation of this memo will encapsulate IPX datagrams in UDP packets in the same way any hardware implementation might encapsulate IPX datagrams in that hardware's frames. IPX networks can be connected thusly across internets that carry only IP traffic. Packet Format Each IPX datagram is carried in the data portion of a UDP packet. All IP and UDP fields are set normally. Both the source and the destination ports in the UDP packet should be set to the UDP port value allocated by the Internet Assigned Numbers Authority for the implementation of this encapsulation method. As with any UDP application, the transmitting party has the option of avoiding the overhead of the checksum by setting the UDP checksum to zero. Since IPX implementations never use the IPX checksum to guard IPX packets from damage, UDP checksumming is highly recommended for IPX encapsulation. Provan [Page 1] RFC 1234 IPX on IP June 1991 +---------------------+------------+-------------------------------+ | | | | | | IP Header | UDP Header | IPX Header | IPX packet data | | (20 or more octets) | (8 octets) | (30 octets) | | | | | | | +---------------------+------------+-------------------------------+ Figure 1: An IPX packet carried as data in a UDP packet. Reserved Packets The first two octets of the IPX header contain the IPX checksum. IPX packets are never sent with a checksum, so every IPX header begins with two octets of FF hex. Implementations of this encapsulation scheme should ignore packets with any other value in the first two octets immediately following the UDP header. Other values are reserved for possible future enhancements to this encapsulation protocol. Unicast Address Mappings IPX addresses consist of a four octet network number and a six octet host number. IPX uses the network number to route each packet through the IPX internet to the destination network. Once the packet arrives at the destination network, IPX uses the six octet host number as the hardware address on that network. Host numbers are also exchanged in the IPX headers of packets of IPX's Routing Information Protocol (RIP). This supplies end nodes and routers alike with the hardware address information required for forwarding packets across intermediate networks on the way towards the destination networks. For implementations of this memo, the first two octets of the host number will always be zero and the last four octets will be the node's four octet IP address. This makes address mapping trivial for unicast transmissions: the first two octets of the host number are discarded, leaving the normal four octet IP address. The encapsulation code should use this IP address as the destination address of the UDP/IP tunnel packet. Broadcasts between Peer Servers IPX requires broadcast facilities so that NetWare servers and IPX routers sharing a network can find one another. Since internet-wide IP broadcast is neither appropriate nor available, some other mechanism is required. For this memo, each server and router should maintain a list of the IP addresses of the other IPX servers and Provan [Page 2] RFC 1234 IPX on IP June 1991 routers on the IP internet. I will refer to this list as the "peerShow full document text