IS-IS Hello Messages on LAN
Question
By default, how often does a designated intermediate system (DIS) send IS-IS hello messages on a LAN?
Answers
Explanations
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A. B. C. D.A
The default time period for most IS-IS hellos is every 9 seconds, however a DIS sends them every 3 seconds.
IS-IS (Intermediate System to Intermediate System) is a link-state routing protocol that is used for routing within an autonomous system (AS) in a network. It operates by exchanging link-state packets (LSPs) with other routers in the network to build a complete map of the network topology.
In a multi-access network such as a LAN, a designated intermediate system (DIS) is elected to act as the intermediary between the other routers in the network. The DIS is responsible for forwarding LSPs to other routers and ensuring that all routers have the same view of the network topology.
The DIS sends IS-IS hello messages to other routers on the LAN to establish and maintain neighbor relationships. These hello messages are sent periodically, and the frequency of these messages can be configured.
By default, the DIS sends IS-IS hello messages every 10 seconds on a LAN. This interval can be configured using the hello-interval command in the IS-IS configuration.
So, the correct answer to the question is C. every 10 seconds.
