There's been enough discussion about area and router relationships, admittedly more with respect to OSPF than ISIS, that this seemed relevant. Radia is the principal architect of ISIS. >From: Radia Perlman - Boston Center for Networking <[EMAIL PROTECTED]> > >Subject: RE: [Isis-wg] (no subject) area/router boundary > >Date: Mon, 29 Jan 2001 11:09:40 -0500 (EST) > >Although all the replies have been correct, let me either clarify >or confuse things with a bit of history. Originally IS-IS was >designed for CLNP addresses, where the top part of the address (everything >but the ID portion) was the "area", so an address specified >an area, and a node could have lots of links in that area all >with the same address, but only be in one area. So a node, by >definition, if >"node" is defined by the address of the node, could only exist in >one area. > >With IS-IS for IP, though, this didn't really apply anymore since >a node has an address for each interface. > >But even with CLNP, it was possible to implement what looked to >the rest of the world like two nodes by having a router run >multiple instances of IS-IS, one for each (level 1) area, and >then the router could exist in both areas, and even pass routing >summaries between them. This was implemented in NLSP, a variant >of IS-IS for IPX. Such an implementation is straightforward >and completely compatible >with current IS-IS routers, who wouldn't be able to tell the >difference between such a beast and two routers. > >But the spec does say a router is in (at most) one level 1 area, and >might also >be a level 2 router, as someone on this thread pointed out. > >Radia > > > > > > > -----Original Message----- > > From: Volkan Ozdemir [mailto:[EMAIL PROTECTED]] > > Sent: Thursday, January 25, 2001 3:37 PM > > To: [EMAIL PROTECTED] > > Subject: [Isis-wg] (no subject) > > > > > > > > Hi, > > > > I had a basic question about IS-IS. In IS-IS is a > > router completely in a single area or is it possible to > > assign interfaces to different areas? > > > > Thanks > > > > Volkan > >_______________________________________________ >Isis-wg mailing list - [EMAIL PROTECTED] >http://external.juniper.net/mailman/listinfo/isis-wg _________________________________ FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
