BROCADE IP PRIMER

Summary• show ip ospf virtual-link — Displays information about configured VirtualLinks; make sure that you see “ptr 2 ptr”; if you don't, your Virtual Link isnot active• show ip ospf trap — Displays the state of all OSPF-related SNMP trapsdefined• show ip ospf border — Displays information about all ABRs and ASBRs• show ip ospf config — This command is often overlooked, but it's awfullyhandy if you've got a switch with a very large config; this will show you justthe section of the config pertaining to OSPFSummary• OSPF is a link state protocol— It uses a link's state and cost to make its routing decisions— It uses Dijkstra's algorithm to calculate the Shortest Path— After adjacency is reached, routers only send updates as they occur— It uses multicast to send its messages• Neighbors are routers that have interfaces that share the same broadcastdomain• OSPF routers use Hello packets to negotiate a conversation and to verifyhealth• The Designated Router (DR) and Backup Designated Router (BDR) receiveall updates for a given broadcast multi-access segment• The Designated Router (DR) forwards updates to the rest of the routers onits segment• The Designated Router and Backup Designated Router are chosenthrough an election— The router with the highest priority becomes Designated Router— The router with the second highest priority becomes Backup DesignatedRouter— Should the Designated Router fail, the Backup Designated Routerwill immediately become the Designated Router, and an election willbe held to see who becomes the Backup Designated Router• Areas subdivide and group different OSPF routers• All OSPF configurations must have at least one area: Area 0 - theBackbone• All areas must physically connect to Area 0• All inter-area traffic must travel through Area 0Brocade IP Primer 257