Link-state routing protocol: Difference between revisions

Revision as of 21:45, 11 November 2020

Revision as of 22:44, 16 November 2020

Line 36:

* Includes a 'sequence number', which increases every time the source node makes up a new version of the message''.''

This message is sent to all the nodes on a network. As a necessary precursor, each node in the network remembers, for every one of ''its'' neighbors, the sequence number of the last link-state message which it received from that node. When a link-state advertisement is received at a node, the node looks up the sequence number it has stored for the source of that link-state message: if this message is newer (i.e., has a higher sequence number), it is saved, the stored sequence number is updated, and athe copymessage is sent in turn to each of that node's neighbors, except the one from which the message was received and the original source of the message. Otherwise (if the sequence number of the message is less than or equal to the stored sequence number for the source), the message is discarded, since it has already been processed by this node before and has reached this node again via another neighbor. This procedure rapidlyensures getsthat aevery copynode ofin the network receives the latest version of each node'sa link-state advertisement, toand everydoes nodeso in thefinite networktime (without sending messages back and forth between nodes in a cycle).

Networks running link state algorithms can also be segmented into hierarchies which limit the scope of route changes. These features mean that link state algorithms scale better to larger networks.