OSPF (Open Shortest Path First) Summary

Here is a list of the most important OSPF features:

  • link state routing protocol
  • classless routing protocol
  • supports VLSM (Variable Length Subnet Mask)
  • converges fast
  • uses the concept of areas
  • uses multicast address for routing updates ( and
  • sends partial routing updates
  • supports only equal cost load balancing
  • manual summarization can be done only on ABRs and ASBRs
  • uses interface cost as a metric
  • uses SPF algorithm to calculate the best paths
  • open standard
  • each router inside an area has the same topology table
  • supports clear-text and MD5 authentication

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