ECS4660-28F_Management Guide-R03

C HAPTER 51 | IP Routing Commands
Open Shortest Path First (OSPFv2)
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◆ Set the priority to zero to prevent a router from being elected as a DR
or BDR. If set to any value other than zero, the router with the highest
priority will become the DR and the router with the next highest priority
becomes the BDR. If two or more routers are tied with the same
highest priority, the router with the higher ID will be elected.
◆ If a DR already exists for a network segment when this interface comes
up, the new router will accept the current DR regardless of its own
priority. The DR will not change until the next time the election process
is initiated.
◆ Configure router priority for multi-access networks only and not for
point-to-point networks.
EXAMPLE
Console(config)#interface vlan 1
Console(config-if)#ip ospf priority 5
Console(config-if)#
ip ospf
retransmit-interval
This command specifies the time between resending link-state
advertisements (LSAs). Use the no form to restore the default value.
SYNTAX
ip ospf [ip-address] retransmit-interval seconds
no ip ospf [ip-address] retransmit-interval
ip-address - This parameter can be used to indicate a specific IP
address connected to the current interface. If not specified, the
command applies to all networks connected to the current interface.
seconds - Sets the interval at which LSAs are retransmitted from
this interface. (Range: 1-65535)
COMMAND MODE
Interface Configuration (VLAN)
DEFAULT SETTING
5 seconds
COMMAND USAGE
◆ A router will resend an LSA to a neighbor if it receives no
acknowledgment after the specified retransmit interval. The retransmit
interval should be set to a conservative value that provides an
adequate flow of routing information, but does not produce
unnecessary protocol traffic. Note that this value should be larger for
virtual links.
◆ Set this interval to a value that is greater than the round-trip delay
between any two routers on the attached network to avoid unnecessary
retransmissions.