Link-state routing protocol

A link-state routing protocol is a network protocol that is used by routers to build up a complex database with topology details. Using this database, the packets are then forwarded in the network.

Survey

Link - state routing protocols operate quite differently than distance-vector protocols such as RIP or IGRP. Distance vector protocols usually exchange only information about the reachable networks with their immediate neighbors and have no knowledge of the complete network topology. In contrast to them, the routing information that is exchanged in link-state routing protocols between the routers, complex.

Classless Inter- Domain Routing CIDR and VLSM subnet masks with variable length are supported by all link-state routing protocols.

Operation

If there are many changes in the routing table and the routing table must be updated often or regularly, it is advisable to use a link-state routing protocol. Only the respective changes among the routers to be replaced. When link-state routing are sent by flooding to all neighboring routers to changes in the network called LSA ( Link-State-Announcement/Advertisements ). In the topology database, each router on the basis of the received LSA generates the entire topology of the network. Since the connection-oriented changes to be propagated to the neighboring router, routing protocols have a good convergence with the LSA.

The link - state algorithm is the practical implementation of the mathematical Dijkstra algorithm.

Features of link-state routing

• Works with SPF Algorithm ( Shortest Path First ) and resulting SPF tree.
• Regular updates ( link-state updates) by Flooding
• Determine the reachability of neighbors with Hello protocol
• Rapid response to network change: The SPF algorithm computes the LSA information the optimal paths and updates the routing table (local)
• The routing table including the path costs and interfaces for every known network to determine the optimum path for the packages.