Area Border Routers (ABR) ??

[lifebook567]

"In OSPF, if traffic must travel between two areas, the packets are first routed to the backbone." Is that mean, network in different area can talk together? How to configure interarea OSPF? Via Area Border Routers (ABR)? Can ABR be in the same physical router (one interface of the router connect to 1 area and the other interface connect to another area)? Or it needs to be two separate routers, so it can be called ABR?

[vijayasankar]

Hi,

Yes. Nerwork/routers in different areas can talktogether and it will be via Area 0.

Have a look at the OSPF design guide for an idea on Areas of type of Routers.

http://www.cisco.com/en/US/tech/tk365/technologies_white_paper09186a0080094e9e.shtml#t8

A router that has all of its interfaces within the same area is called an internal router (IR). A router that has interfaces in multiple areas is called an area border router (ABR). Routers that act as gateways (redistribution)between OSPF and other routing protocols (IGRP, EIGRP, IS-IS, RIP, BGP, Static) or other instances of the OSPF routing process are called autonomous system boundary router (ASBR). Any router can be an ABR or an ASBR.

Hope this helps.

-VJ