RFC 1362 (rfc1362) - Page 2 of 13

Novell IPX over Various WAN Media (IPXWAN)

RFC 1362                         IPXWAN                   September 1992


   IPX WAN protocol operation begins immediately after link
   establishment. While IPX is a connectionless datagram protocol, WANs
   are often connection-oriented.  Different WANs have different methods
   of link establishment. The subsections of section 1 of this document
   describe what link establishment means to IPX for different media.
   They also describe other WAN-media-dependent aspects of IPX
   operation, such as protocol identification, frame encapsulation, and
   link tear down.

1.1 Operation Over PPP

   IPX uses PPP [1] when operating over point-to-point synchronous and
   asynchronous networks.

   With PPP, link establishment means the IPX NCP [4] reaches the Open
   state. NetWare IPX will reject all NCP options, and uses normal frame
   encapsulation as defined by PPP. The IPXWAN protocol MUST NOT occur
   until the IPX NCP reaches the Open state.

   PPP allows either side of a connection to stop forwarding IPX if one
   end sends an IPXCP or an LCP Terminate-Request. When a router detects
   this, it will immediately reflect the lost connectivity in its
   routing information database instead of naturally aging it out.

1.2 Operation over X.25 Switched Virtual Circuits

   With X.25, link establishment means successfully opening an X.25
   virtual circuit.  As specified in RFC-1356, "Multiprotocol
   Interconnect on X.25 and ISDN in the Packet Mode" [2], the protocol
   identifier 0x800000008137 is used in the X.25 Call User Data field of
   the Call Request frame, and indicates that the virtual circuit will
   be devoted to IPX.

   Furthermore, each IPX packet is encapsulated directly in X.25 data
   frame sequences without additional framing.

   Either side of the virtual circuit may close it, thereby tearing down
   the IPX link. When a router detects this, it will immediately reflect
   the lost connectivity in its routing information database instead of
   naturally aging it out.

1.3 Operation over X.25 Permanent Virtual Circuits

   The nature of X.25 PVC's is that no call request is made.  When the
   router is informed that X.25 Layer 2 is up, the router should assume
   that link establishment is complete.





Allen