OSPF
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Internal versus external routing
To ensure effective processing of network traffic, every routing device on your network needs to know
how to send a packet (directly or indirectly) to any other location/destination in your network. This is
referred to as internal routing and can be done with static routes or using active internal routing protocols,
such as OSPF, RIP, or RIPv2.
It is also useful to tell routers outside your network (upstream providers or peers) about the routes you have
access to in your network. Sharing of routing information between autonomous systems is known as
external routing.
Typically, an AS will have one or more border routers (peer routers that exchange routes with other OSPF
networks) as well as an internal routing system enabling every router in that AS to reach every other
router and destination within that AS.
When a routing device advertises routes to boundary routers on other autonomous systems, it is effectively
committing to carry data to the IP space represented in the route being advertised. For example, if the
routing device advertises 192.204.4.0/24, it is declaring that if another router sends data destined for
any address in the 192.204.4.0/24 range, it will carry that data to its destination.
OSPF implementation in HP 10GbE switch software
The HP 10GbE switch supports a single instance of OSPF and up to 4 K routes on the network. The
following sections describe OSPF implementation in switch software:
• Configurable Parameters
• Defining Areas
• Interface Cost
• Electing the Designated Router and Backup
• Summarizing Routes
• Default Routes
• Virtual Links
• Router ID
• Authentication
Configurable parameters
In HP 10GbE switch software, OSPF parameters can be configured through the Command Line Interface
(CLI), Browser-Based Interface (BBI) for HP 10GbE switches, or through SNMP. For more information, see
“Accessing the Switch.”
The CLI supports the following parameters: interface output cost, interface priority, dead and hello
intervals, retransmission interval, and interface transit delay.
OSPF traps—Traps produce messages upon certain events or error conditions, such as missing a hello,
failing a neighbor, or recalculating the SPF.
In addition to the above parameters, you can also specify the following:
• Link-State Database size—The size of the external LSA database can be specified to help manage
the memory resources on the switch.
• Shortest Path First (SPF) interval—Time interval between successive calculations of the shortest path
tree using the Dijkstra’s algorithm.
