HP ProCurve Secure Router 7203 dl Advanced Management And Configuration Manual page 623

Option RIP
Metric Number of hops to the
computation destination.
and route
selection
Information Routers send the complete
in updates RIP routing table.
The routers • All router interfaces on RIP
that send and networks.
receive
• The interface that receives
updates
a route advertises it as
unreachable (split horizon
with poison reverse).
• Passive interfaces receive
updates but do not send
them.
The intervals • Routers send updates
when routers every 30 seconds.
send and
• Routers send updates
receive
immediately after a
updates
change in network
topology (triggered
updates).
Table 13-1. Routing Protocol Comparison
OSPF
• Inverse bandwidth
• Type of service (ToS) (rarely
used)
Different types of LSAs include
different information:
• a link and its status:
– link to a network
– link to another router
• router ID of every router in a
multi-access network
• summary route to a range of
networks in an area (sent by
ABRs)
• route to autonomous system
border router, or ASBR (sent by
ABRs)
• external routes or default route
for external traffic (sent by
ASBRs)
• In point-to-point networks,
neighboring routers exchange
LSAs.
• In multi-access networks, all
routers send LSAs to a DR and
backup DR (BDR) and receive
LSAs from a DR.
• ABRs send route summaries
into stub areas.
• Neighbors and DRs send LSAs:
– not more than every 5
– not less than every 30
– when topology changes
• Routers send:
– an ACK when they receive an
– a hello every 10 seconds
IP Routing—Configuring RIP, OSPF, BGP, and PBR
seconds
minutes
LSA
Overview
BGP
Variety of policies:
• external or internal route
• number of hops
• autonomous systems through
which the route passes
• weight
• prefix length
Updates include:
• New route.
• Withdrawn routes.
• Routes include autonomous
systems through which
packets must pass.
• Internal filters screen which
routes the router advertises
to a neighbor.
BGP routers communicate only
with manually configured
neighbors.
• Routers only send messages
to update routes.
• Routers can send keepalive
messages.
13-9