3Com Switch 8800 Configuration Guide
Chapter 19 OSPF Configuration
19-15
19.2.9 Setting OSPF Route Preference
Since maybe multiple dynamic routing protocols are running on one router concurrently,
the problem of route sharing and selection between various routing protocols occurs.
The system sets a preference for each routing protocol, which will be used in
tie-breaking in case different protocols discover the same route.
Perform the following configuration in OSPF view.
Table 19-13
Set OSPF route preference
Operation
Command
Configure a preference for OSPF for
comparing with the other routing protocols
preference
[
ase
]
preference
Restore the default protocol preference
undo preference
[
ase
]
By default, the OSPF preference is 10, and that of the imported external routing
protocol is 150.
19.2.10 Configuring OSPF Timers
I. Setting the interval for Hello packet transmission
Hello packets are a kind of most frequently used packets, which are periodically sent to
the adjacent router for discovering and maintaining the adjacency, and for electing DR
and BDR. The user can set the hello timer.
According to RFC2328, the consistency of hello intervals between network neighbors
should be kept. The hello interval value is in inverse proportion to the route
convergence rate and network load.
Perform the following configuration in interface view.
Table 19-14
Set the interval for Hello packet transmission
Operation
Command
Set the hello interval of the interface
ospf timer hello
seconds
Restore the default hello interval of the interface
undo ospf timer hello
Set the poll interval on the NBMA interface
ospf timer poll
seconds
Restore the default poll interval
undo ospf timer poll
By default, p2p and broadcast interfaces send Hello packets every 10 seconds, and
p2mp and nbma interfaces send packets every 30 seconds.
