IP R
OUTING
3-317
interface when estimating this delay. Set the transmit delay according
to link speed, using larger values for lower-speed links.
- The transmit delay must be the same for all routers in an autonomous
system.
- On slow links, the router may send packets more quickly than devices
can receive them. To avoid this problem, you can use the transmit
delay to force the router to wait a specified interval between
transmissions.
• Retransmit Interval – Sets the time between resending link-state
advertisements. (Range: 1-65535 seconds; Default: 1)
- A router will resend an LSA to a neighbor if it receives no
acknowledgment. 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.
• Hello Interval – Sets the interval between sending hello packets on an
interface. (Range: 1-65535 seconds; Default: 10)
- This interval must be set to the same value for all routers on the
network.
- Using a smaller Hello interval allows changes in the network topology
to be discovered more quickly, but may result in more routing traffic.
• Rtr Dead Interval – Sets the interval at which hello packets are not seen
before neighbors declare the router down. This interval must be set to
the same value for all routers on the network. (Range: 1-65535 seconds;
Default: 40, or 4 times the Hello Interval)
• Cost – Sets the cost of sending a packet on an interface, where higher
values indicate slower ports. (Range: 1-65535; Default: 1)
- This router uses a default cost of 1 for all ports. Therefore, if you
install a Gigabit module, you need to reset the cost for all of the 100
Mbps ports to some value greater than 1.