Alex, If this is a big concern and you have the option, check out IS-IS.
Eric :) On Mon, Nov 30, 2009 at 03:09:31PM -0000, Alex wrote: > Drew, > If your VLANs are all covered by "network X.Y.Z.W area V" command under > "router ospf T" then they all are represented as Type-1/Type-2 LSA in OSPF > LSDB. > And every time a VLAN goes down, LSA-1/2 are reflooded with Age=MaxAge > (default 3600 sec). > When this VLAn goes back up, LSA-1/2 are recreated and reflooded again. > Every time this happens, all OSPF routers in given area must recalculate > their SPF, then put OSPF routes in a routing table with new timestamp. > I'd suggest to use OSPF "network" statement for core VLANs only, edge VLANs > should be injected with "redistrubute connected/static" statement (this > creates Type-5 LSA for edge VLANs which does not affect SPF). > HTH > Rgds > Alex > > > -------------------------------------------------- > From: "Drew Weaver" <[email protected]> > Date: 30 November 2009 14:39 > To: "Cisco-nsp" <[email protected]> > Subject: [c-nsp] OSPF clarification > > >Hi, > > > >If you have your entire network in a single area (area 0), is it normal > >that when a VLAN on any switch in that area flaps that all of your routes > >in OSPF 'reset'? > > > >I don't mean a 'neighbor' VLAN, I mean just any old VLAN with an IP > >address assigned to it. > > > >Last update from x.x.x.x on Vlan4061, 00:08:42 ago > > > >I mean the 'timers' seem to reset for every single route in OSPF anytime a > >single VLAN anywhere goes down. > > > >If this is intended, which I am still not sure of, what would be the > >proper way to 'area' a datacenter? > > > >It doesn't seem like there would be a way to do it so that just the route > >attached to said VLAN that is flapping would be removed/re-inserted unless > >you put each VLAN in a separate area. > > > >thanks, > >-Drew > > > > > > > >_______________________________________________ > >cisco-nsp mailing list [email protected] > >https://puck.nether.net/mailman/listinfo/cisco-nsp > >archive at http://puck.nether.net/pipermail/cisco-nsp/ > > > _______________________________________________ > cisco-nsp mailing list [email protected] > https://puck.nether.net/mailman/listinfo/cisco-nsp > archive at http://puck.nether.net/pipermail/cisco-nsp/ _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
