O'Reilly logo

CCIE Routing and Switching Exam Quick Reference Sheets by Anthony Sequeira

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

Chapter 4. IP Routing

Open Shortest Path First

Open Shortest Path First (OSPF) link-state routing protocol is designed to be more scalable and efficient than Routing Information Protocol (RIP). Some OSPF features you should be aware of are as follows:

  • Runs on IP and uses protocol 89.
  • Classless with variable-length subnet mask (VLSM) support.
  • Uses multicasts (224.0.0.5—all shortest path first [SPF] routers; 224.0.0.6—Designated Router [DR]/Backup Designated Router [BDR]) for hellos and updates.
  • Plain text and Message Digest Algorithm 5 (MD5) authentication available.
  • Dijkstra's algorithm is used to produce a shortest-path tree for each destination. Link-state advertisements are used to build a database of the topology.

OSPF packet types

  • Type ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required