Icnd2 ospf

alliasneo

I thought I would try and start a thread on everything I've been learning for the CCNA on OSPF.

So far I know that:

Hello and Dead Timers must match.
On a non-broadcast segment (such as serial interfaces and Frame-relay) you won't have a DR/BDR.
DR & BDR are elected on broadcast segments such as Ethernet.
Subnet masks much match for neighbor adjacencies.
Area 0 is backbone.
Updated are multicast to 224.0.0.5
Wildcard Masks are used in OSPF network statements.

......

MrXpert

NBMA Do elect DR/BDR but you must manually configure them

Point to point and point to multipoint do not elect DR/BDR

Hello timer and dead timers for point to point and broadcast are 10/40 seconds by default
Multipoint and NBMA are 30/120 seconds

Internal routers=a router which has all its OSPF enabled interfaces in one area apart from area 0
Area Border Router=a router which has an ospf enabled interface in area 0 and an interface in another area
ASBR=router which performs route injection/redistribution into OSPF area. These routers contain a connection to a seperate AS such as the internet.
All ABRs are Backbone routers but not all backbone routers are ABRs.
Some discussions amoung CCIEs say that backbone routers can be internal routers.