3Com Switch 7700, Configuration Manual

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112 C
HAPTER
5: IP R
OUTING
P
ROTOCOL
O
PERATION
adjacent router of the interface, and whether the adjacent router is eligible for
election. This can be done by configuring the
peer ip-address command. If
dr-priority-number is not specified, the adjacent router will be regarded as
ineligible.
Perform the following configuration in OSPF view.
By default, the preference for the neighbor of NBMA interface is 1.
Setting the Interval of Hello Packet Transmission
Hello packets are the most frequently sent packets. They are periodically sent to
the adjacent router for discovering and maintaining adjacency, and for electing a
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 VLAN interface view.
By default, P2P and broadcast interfaces send Hello packets every 10 seconds, and
P2MP and NBMA interfaces send the packets every 30 seconds.
Setting a Dead Timer for the Neighboring Routers
If hello packets are not received from a neighboring router, that router is
considered dead. The dead timer of neighboring routers refers to the interval after
which a router considers a neighboring router dead. You can set a dead timer for
the neighboring routers.
Perform the following configuration in VLAN interface view.
Table 30 Configuring the Peer
Operation Command
Configure a peer for the NBMA interface. peer ip-address [ dr-priority
dr-priority-number ]
Remove the configured peer for the NBMA
interface undo peer ip-address
Table 31 Setting Hello Timer and Poll Interval
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
Table 32 Setting a Dead Timer for the Neighboring Routers
Operation Command
Configure a dead timer for the neighboring
routers ospf timer dead seconds