Installing and Administering Internet Services

238 Chapter 8
Configuring gated
Overview
• gated translates among several protocols, passing information
within or between IP routing domains or autonomous systems.
“Autonomous system” is used here to refer to a group of connected
nodes and routers in the same administrative domain that are
exchanging routing information via a common routing protocol.
• gated gives the system administrator flexibility in setting up and
controlling network routing. For example, gated can listen to
network traffic at specified routers, determine available routes, and
update local routing tables accordingly.
When to Use gated
gated is most often used in large networks, or small networks connected
to larger wide-area networks.
gated should be run on routers (gateways) so its routing information can
be sent to other routers. gated supports many routing protocols that
allow routers to build and maintain dynamic routing tables. However,
gated also supports RIP (Routing Information Protocol), which can run
on end systems (systems with only one network interface) as well as
routers.
gated is useful in topologies with multiple routers and multiple paths
between parts of the network. gated allows the routers to exchange
routing information and dynamically change routing information to
reflect topology changes and maintain optimal routing paths.
Alternatively, you may configure IP routes manually with the route
(1M) command. For end systems in subnets with only one router
(gateway) to the rest of the internet, manually configuring a default
route is usually more efficient than running gated. Type man 1M route
at the HP-UX prompt.
When connected to wide-area networks, gated can be used to inject local
routing information into the wide-area network’s routing table.
Protocols
For routing purposes, networks and gateways are logically grouped into
autonomous systems. An autonomous system (AS) is a set of networks
and gateways that is administered by a single entity. Companies and