Technical data

Configuring Routing
4.1 Key Concepts
TCP/IP Services implements two routing daemons: the Routing Daemon
(ROUTED) and the Gateway Routing Daemon (GATED). The following sections
provide more information.
4.1.2.1 Routing Daemon (ROUTED)
This daemon (pronounced route-dee) supports the Routing Information Protocol
(RIP). When ROUTED starts, it issues routing update requests then listens for
responses. A system configured to supply RIP information responds to the request
with an update packet. The update packet contains destination addresses and
routing metrics associated with each destination. After receiving a RIP update,
the ROUTED uses the information to update its routing table.
To configure dynamic routing with ROUTED, see Section 4.3.
4.1.2.2 Gateway Routing Daemon (GATED)
This daemon (pronounced gate-de) supports interior and exterior gateway
protocols. It obtains information from several routing protocols and selects
the best routes based on that information. You can configure GATED to use one
or more of the protocols described in Table 4–1.
Table 4–1 GATED Routing Protocols
Protocol RFC Description
Routing Information
Protocol (RIP) Versions
1 and 2
RFC 1058, RFC 1723 RIP is a commonly used interior protocol that selects
the route with the lowest metric (hop count) as the
best route.
Open Shortest Path
First (OSPF) Version 2
RFC 1583 Another interior routing protocol, OSPF is a link-
state protocol (shortest path first) and better suited
than RIP for use in complex networks with many
routers.
Exterior Gateway
Protocol (EGP)
RFC 904 EGP exchanges reachability information between
autonomous systems. An autonomous system is
usually defined as a set of routers under a single
administration, using an interior gateway protocol
and common metric to route packets. Autonomous
systems use exterior routing protocols to route
packets to other autonomous systems.
Border Gateway Protocol
(BGP)
RFCs 1163, 1267, 1771 Like EGP, BGP exchanges reachability information
between autonomous systems but supports
nonhierarchical topologies. BGP uses path
attributes to provide more information about each
route. Path attributes can include, for example,
administrative preferences based on political,
organizational, or security considerations.
Router Discovery RFC 1256 This protocol is used to inform hosts of the
availability of routers that it can send packets
to, and to supplement a statically configured default
router.
These routing protocols are configured in the GATED configuration file
TCPIP$GATED.CONF. This file contains statements that control tracing options,
select routing protocols, manage routing information, and manage independent
system routing.
For information on configuring dynamic routing with GATED, see Section 4.4.
4–2 Configuring Routing