Quick Notes – OSPF

• The Neighbor IP used with OSPF distance command is the Neighbors Router-ID.

• “area range” summarize type 3 LSA’.
• “summary-address” summarize type 5 & 7 LSA’s.
• Auto-cost reference BW (Default = 100mb), formula = Ref-BW/Int-Bw.
• Switches do not support the interface command “ip ospf {pid} area {area-id}” .
• OSPF path selection: O > O*IA > O*E1 > O*E2.
• Using E1 metric type : Packets will be routed out the closest exit point of the network. (sum of path cost between router to next hop and next hop to destination)
• Using E2 metric type : If you want packets to exit your network at the closest point to their external destination. (path cost from next hop to destination)
• Don’t forget with hub and spoke topology, “ip ospf priority 0″.
• “no capability transit” – Mimics OSPFv1 behaviour for all data traffic to pass through Area-0.
• “max-metric” – Configures OSPF stub configurations
• “max-lsa” – Limit amount of non-local LSA’s
• “timers throttle lsa all” – Slow down update rate.
• “timers pacing lsa-group” – Group more LSA’s together in updates.
• “no ip ospf flood-reduction” – Disables every 30-min LSA DB refresh.
• “ip ospf database filter all out” – Breaks RFC, Stop sending LSA’s, but still receive LSA’s