Introduction To Ipx - Bay Networks Nautica 200 Reference Manual

NauticaRS Release 4.1 Reference Guide

Introduction to IPX

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An important consideration is how long it takes for a change to
the routing topology (such as link or node failure) to be
transmitted through the entire RIP network environment. This
process is called convergence, and it is important that it occurs as
fast as possible so that all routers have correct information about
the changed network in their tables. Using RIP, convergence
takes place 1 hop at a time throughout the entire network, with
new routing information being passed from one hop to another
using the 30-second routing information timer. So, to prevent this
taking too long, RIP is limited to 15 hops maximum.
Nautica Series routers support both RIP1 and RIP2. RIP2 has
several enhancements, including the ability to transmit
sub-address information with the routing table, allowing
networks with variable-length sub-networks to be supported.
The Nautica Series also supports Novell's IPX protocol. The IPX
protocol provides a connectionless datagram delivery service,
providing both internetwork addressing and intranode
addressing (sockets). IPX's major task is to deliver packets from
one source on the internetwork to a destination at another place
on the internetwork.
IPX RIP is responsible for advertising the best route to a node,
and for assigning a workstation's network address. IPX achieves
this in two ways:
• Broadcast an unsolicited IPX RIP message (every 30
seconds).
• Respond to a Get Target Request.
This second method is requested by a node to determine the
fastest path to a particular destination, and is responded to by the
router attached to the local network. By checking the source
address of the response message, the client workstation can
determine its own network number.
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