Link state protocols (contd)

• Sequence numbers have a wrap-around problem => responsible for early ARPAnet crashes.
• Age field (similar to TTL) + Sequence number if handled correctly is usually sufficient

• Dijkstra’s (“Shortest Path First” (SPF)) algorithm:
  • Assume that the following databases are present:
    • Link state DB: latest LSP from each router
    • PATH: (ID, path cost, forwarding direction) triples. Set of of nodes for which the best path’s cost & forwarding direction have been found
    • TENTATIVE: (ID, path cost, forwarding direction)

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