Explanation of an OSPF Area
ID: Q168515
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The information in this article applies to:
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Microsoft Windows NT Server version 4.0
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Microsoft Routing and Remote Access Service Update for Windows NT Server 4.0
SUMMARY
An Autonomous System (AS) in an Open Shortest Path First (OSPF) routed
network can be broken up into areas. An OSPF area, based on the same
concept as IP subnets, consists of a group of networks logically linked
and sharing a single link state database (LSDB).
MORE INFORMATION
Routers within a single area maintain the same LSDB and communicate this
information to each other by flooding the area with link state
advertisements (LSA).
A router that is connected to more than one area is called an area border
router (ABR). ABRs are most commonly used to connect tie areas together by
being connected its own area and the backbone area. An area border router
advertises a summary of its area information to other area border routers
using summary advertisements. This area topology significantly reduces the
amount of traffic between routers. It also reduces the size of the LSDB
within an area. Since the LSDB is used to calculate the SPF, this size
reduction can be a significant performance enhancement on the router.
Area ID's are 32-bit numbers and in dotted decimal notation. The area ID
is in no way related to the IP address of a network. However, it is
possible to logically associate these numbers for administrative
convenience.
Additional query words:
prodnt 4.00 steelhead rras
Keywords : kbnetwork nttcp ntrouter NTSrv
Version : WinNT:4.0
Platform : winnt
Issue type :