Microsoft ES4625, ES4649 manual 244

3 Configuring the Switch

-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.

-Routes are subsequently assigned a metric equal to the sum of all metrics for each interface link in the route.

•Authentication Type – Specifies the authentication type used for an interface. (Options: None, Simple password, MD5; Default: None)

-Use authentication to prevent routers from inadvertently joining an unauthorized area. Configure routers in the same area with the same password or key.

-When using simple password authentication, a password is included in the packet. If it does not match the password configured on the receiving router, the packet is discarded. This method provides very little security as it is possible to learn the authentication key by snooping on routing protocol packets.

-When using Message-Digest 5 (MD5) authentication, the router uses the MD5 algorithm to verify data integrity by creating a 128-bit message digest from the authentication key. Without the proper key and key-id, it is nearly impossible to produce any message that matches the prespecified target message digest.

-The Authentication Key and Message Digest Key-id must be used consistently throughout the autonomous system. (Note that the Message Digest Key-id field is disabled when this authentication type is selected.)

•Authentication Key – Assign a plain-text password used by neighboring routers to verify the authenticity of routing protocol messages. (Range: 1-8 characters for simple password or 1-16 characters for MD5 authentication; Default: no key)

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