Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!proteon.com!jmoy
From: jmoy@proteon.com (John Moy)
Newsgroups: comp.protocols.tcp-ip
Subject: OSPF Area Routing
Message-ID: <8909121349.AA04116@monk.proteon.com>
Date: 12 Sep 89 13:49:38 GMT
References: <878@cgch.UUCP>
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
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Heinz-

OSPF is an Internal Gateway Protocol, which means that it is a routing
protocol that runs internal to a single Autonomous System. OSPF further
lets you break the Autonomous System into areas. OSPF areas provide a
means for hiding, condensing and protecting routing information.

OSPF areas are defined to be lists of IP address ranges. This means
that several subnetted networks can be contained within a single OSPF
area; for example, if the two class B networks 128.185.0.0 and
128.186.0.0 are subnetted, an OSPF area could be defined as:

	OSPF area 1:	128.185.0.0 - 128.185.255.255 and
			128.186.0.0 - 128.186.255.255

Alternatively, a single subnetted network can be broken up into
multiple OSPF areas. This is what I think you would want to do. For
example, the above subnetted network 128.185.0.0 could be split into
the OSPF areas:

	OSPF area 1:	128.185.0.0 - 182.185.15.255
	OSPF area 2:	128.185.16.0 - 128.185.31.255
			...
	OSPF area 16:	128.185.240.0 - 128.185.255.255

The OSPF specification is available for anonymous ftp from the
Internet Engineering Task Force's Internet-Draft directory on
NIC.DDN.MIL. It's in postscript format, file name
DRAFT-IETF-OSPFIGP-SPEC-07.PS.

John