Netgear XCM8810 - 8800 SERIES 10-SLOT CHASSIS SWITCH ハードウェアマニュアル
Chapter 23. OSPF Commands
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23.
OSPF Commands
This chapter describes commands used for the interior gateway protocol OSPF.
Open Shortest Path First (OSPF) is a link-state protocol that distributes routing information
between routers belonging to a single IP domain, also known as an autonomous system (AS). In
a link-state routing protocol, each router maintains a database describing the topology of the
autonomous system. Each participating router has an identical database maintained from the
perspective of that router.
between routers belonging to a single IP domain, also known as an autonomous system (AS). In
a link-state routing protocol, each router maintains a database describing the topology of the
autonomous system. Each participating router has an identical database maintained from the
perspective of that router.
From the link-state database (LSDB), each router constructs a tree of shortest paths, using itself
as the root. The shortest path tree provides the route to each destination in the autonomous
system. When several equal-cost routes to a destination exist, traffic can distributed among
them. The cost of a route is described by a single metric.
as the root. The shortest path tree provides the route to each destination in the autonomous
system. When several equal-cost routes to a destination exist, traffic can distributed among
them. The cost of a route is described by a single metric.
OSPF allows parts of a networks to be grouped together into areas. The topology within an area
is hidden from the rest of the autonomous system. Hiding this information enables a significant
reduction in link-state advertisement (LSA) traffic, and reduces the computations needed to
maintain the LSDB. Routing within the area is determined only by the topology of the area.
is hidden from the rest of the autonomous system. Hiding this information enables a significant
reduction in link-state advertisement (LSA) traffic, and reduces the computations needed to
maintain the LSDB. Routing within the area is determined only by the topology of the area.
The three types of routers defined by OSPF are as follows:
•
Internal Router (IR)—An internal router has all of its interfaces within the same area.
•
Area Border Router (ABR)—An ABR has interfaces belonging to two or more areas. It
is responsible for exchanging summary advertisements with other ABRs.
•
Autonomous System Border Router (ASBR)—An ASBR acts as a gateway between
OSPF and other routing protocols, or other autonomous systems.
Each switch that is configured to run OSPF must have a unique router ID. It is recommended
that you manually set the router ID of the switches participating in OSPF, instead of having the
switch automatically choose its router ID based on the highest interface IP address. Not
performing this configuration in larger, dynamic environments could result in an older LSDB
remaining in use.
that you manually set the router ID of the switches participating in OSPF, instead of having the
switch automatically choose its router ID based on the highest interface IP address. Not
performing this configuration in larger, dynamic environments could result in an older LSDB
remaining in use.
Note:
Do not set the router ID to 0.0.0.0.
For information about licensing requirements, see Appendix A in the NETGEAR 8800 User
Manual.
Manual.