Monday, April 28, 2008

Split Horizon in EIGRP

Unlike RIP, split horizon is never automatically disabled in EIGRP. Consequently, if you have a hub-and-spoke frame setup with EIGRP overlayed, make sure you disable split horizon with the interface level command:

ccie(config-if)#no ip split-horizon eigrp 100

Sunday, April 13, 2008

RIP Triggered

  • Only send information on link when there is a change in routing database
  • Periodic updates are suppressed
  • Command ('ip rip triggered') is required on both sides of the link
  • Must be a point-to-point link

OSPF Demand Circuit

  • No periodic heartbeat keepalives (hellos)
  • 'Do not age' flag is set on all LSAs so the paranoid 30 min timer doesn't expire
  • Updates will only be sent when there is a change in the OSPF topology
  • Must be a point-to-point link for OSPF
  • Command is only needed on one side