Maxtor RIP3 user guide

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Networks

Tech Note #3

Routing Information Protocol (RIP)

Summary

This document describes the use of RIP in the Matrox iSwitch 8. It contains the following:



A list of the products that support this feature.

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A Description of RIP and the features that this implementation supports.

Applicability

This feature is available in the following products:

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RIP Version 1 - The Matrox iSwitch 8.

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RIP Version 2 - The Matrox iSwitch 8.

RIP

What Is It?

RIP stands for Routing Information Protocol. It allows different routers to exchange information
regarding their network topology. With RIP, a router sends packets to different networks in a
reliable and efficient manner. One can add the routing information manually to a static routing
table found in each router but RIP allows for the automatic generation of this information.
RIP also sends out periodic updates to dynamically update the routing information in the case of
network failures or reconfiguration.

RFC 1058 details RIP version 1, while RFC's 1721 through 1724 detail RIP version 2.

How Does It Work?

RIP works in two ways.
The first is “triggered mode”. The router sends a request for routing information and the reply

contains the routes necessary to reach the desired destination.
The second is “periodic mode”, or “advertising the routes”. Each router broadcasts (RIP Version

1) or multicasts (RIP Version 2) their entire routing table every 30 seconds. The “periodic mode”
keeps other routers aware of the presence of that router and the validity of the various routes for
which it is responsible. If, during a three minute period, a route does not advertise itself a
deletion process begins. If, after a further two minutes, there is still no advertisement of that
particular route the routers on the network delete that route from their list of viable routes.

The Matrox iSwitch 8 differs from traditional routers since it does not exchange RIP packets
through the Internet (WAN), allowing RIP packets to only flow on the LAN. Despite this, the
RIP implementation on the Matrox iSwitch 8 serves two purposes. First, by maintaining a
routing table the Matrox iSwitch 8 knows where to send reply packets on different networks, as
needed. Second, the Matrox iSwitch 8 advertises itself as the default gateway. Other routers

© Matrox Networks 1999

TechNote #3 - RIP Page 2 of 2

can then send all requests for which a route does not exist to the Matrox iSwitch 8. It will, in
turn, forward these destination unknown packets to the Internet. The routers should know all the
available LAN routes. Therefore, any unknown requests must be destined for the Internet
(WAN).

What You Should Know

1. If the Matrox iSwitch 8 is the only device on the LAN capable of routing, then disable the
RIP feature. This feature is only beneficial when there is more than one router on your LAN.
This includes any or all Matrox iSwitch 8 devices. With only one such device on your
network, the Matrox iSwitch 8, it would be a waste of bandwidth to enable RIP.

2. The Matrox iSwitch 8 requests a “triggered” update only when first turning on or resetting
the Matrox iSwitch 8.

3. The Internet, through the ISP connection, does NOT receive RIP from the LAN. RIP data
received from the Internet is NOT used to update the Matrox iSwitch 8 routing tables.
Instead, the ISP router to which the Matrox iSwitch 8 connects takes care of any required
forwarding on the Internet.

4. If a Router does not accept default gateway advertisements, it must be configured manually.
You must manually enter the default gateway on Windows NT routers.

5. Ensure that the routers on the LAN are in active mode. Active mode allows the router to both
listens for and sends RIP packets. Some routers, such as the Matrox iSwitch 8, work in
passive mode by default. In this case, the router will only listen for RIP packets.

6. The only authentication type supported by the Matrox iSwitch 8 RIP implementation is a
plain text password.

© Matrox Networks 1999