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Unformatted text preview: tonomous system. This is called an interior gateway protocol (IGP) or
intradomain routing protocol. The most popular IGP has been the Routing Information
Protocol (RIP). A newer IGP is the Open Shortest Path First protocol (OSPF). It is intended
as a replacement for RIP. An older IGP that has fallen out of use is HELLO-the IGP used on
the original NSFNET backbone in 1986.
The new Router Requirements RFC [Almquist 1993] states that a router that implements any dynamic
routing protocol must support both OSPF and RIP, and may support other IGPs. Separate routing protocols called exterior gateway protocols (EGPs) or interdomain routing
protocols are used between the routers in different autonomous systems. Historically (and
confusingly) the predominant EGP has been a protocol of the same name: EGP A newer
EGP is the Border Gateway Protocol (BGP) that is currently used between the NSFNET
backbone and some of the regional networks that attach to the backbone. BGP is intended to
replace EGP. 10.3 Unix Routing Daemons
Unix systems often run the routing daemon named routed. It is provided with almost every
implementation of TCP/IP This program communicates using only RIP, which we describe
in the next section. It is intended for small to medium-size networks.
An alternative program is gated. It supports both IGPs and EGPs. [Fedor 1988] describes the
early development of gated. Figure 10.1 compares the various routing protocols supported
by routed and two different versions of gated. Most systems that run a routing daemon
run routed, unless they need support for the other protocols supported by gated.
Daemon Interior Gateway Protocol
HELLO RIP OSPF Exterior Gateway Protocol
EGP BGP * V1 * V2, V3 V1 routed
gated, Version 2 * V1 gated, Version 3 * V1, V2 V2 Figure 10.1 Routing protocols supported by routed and gated.
We describe RIP Version I in the next section, the differences with RIP Version 2 in Section file:///D|/Documents%20and%20Settings/bigini/Docu.../homenet2run/tcpip/tcp-ip-illustrated/dynamic.h...
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This test prep was uploaded on 04/04/2014 for the course ECE EL5373 taught by Professor Guoyang during the Spring '12 term at NYU Poly.
- Spring '12