HP 200 Series Services And Applications page 118

Internet Protocol Routing Service
IP Routing Decisions
Routing Protocols
RIP Routing Information Protocol, RIP, is an interior gateway proto-
col (IGP) for exchanging network reachability and routing information
within an autonomous system. RIP is relatively simple to configure and
is best suited for smaller networks (fewer than 15 hops in diameter),
although it can be configured for a network diameter of up to 127 hops.
Note that using a larger network diameter makes the network prone to the
"slow convergence" or "count to infinity" problems. This is a state in which
some routers have inconsistent information. Also, the network may have
routing loops because routing advertisements must propagate further across
the network. To avoid the slow convergence problem, the HP routers
support RIP with "split horizon updates" and "poison reverse with triggered
updates". To enable RIP to account for different link speeds, the HP routers
allow you to assign a higher cost to interfaces with lower-speed networks.
For further explanation, refer to the "IP Network Interface Definition"
section in the IP chapter in the reference manual.
OSPF Open Shortest Path First, OSPF, is an interior gateway protocol
(IGP) for exchanging network reachability and routing information
either within or between autonomous systems. Configuring OSPF is
more involved than configuring RIP. However, it is much more robust
and is better suited to larger, more complex networks with widely
varying link speeds.
To reduce the amount of traffic generated by advertisements between
routers, OSPF supports "areas" and "designated routers". A network can be
broken into several areas, each consisting of a group of subnetworks and
routers. Within each area, a designated router will be elected. Other routers
in the area will exchange link-state advertisements (LSAs) only with the
designated router, not with each other. Additionally, only those routers with
direct connections to multiple areas will exchange advertisements about the
subnetworks within each of those areas.
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