Tag Archives: Link state

OSPF

OSPF is a link-state routing protoocol which uses factors such as speed or the link’s shortest path to decide which route is the best.

Link state protocol routers maintain a common picture of the network and exchange link informantion during discovery and/or network changes.

OSPF is designed for large and scalable networks, becauses of the following advantages:

  • Convergence speed
    • OSPF sends only routing changes instead of the entire routing table. Because of the small routing changes, updates are flooded rapidly across the network
  • Support for VLSM
  • Network size
  • Use of bandwidth
    • OSPF uses multicast to advertertise the updates: LSU’s (link state updates) are small in packetsize
  • path selection
    • OSPF selects optimal routes using cost instead of hopcount (RIP)
  • Member groupings
    • OSPF uses areas: every network segment is cut into smaller areas of routers: less LSU’s are sent out and more efficient routing takes place. eh Every router in a area does have the same topology table.

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