>Regarding this command... >"Default-information originate [always]" >this is documented as saying... >this generates the default route into OSPF even if the path to the default >route goes down... >and... >even when the router has no default route, with the magic keyword "always" it >will create a "default route"...pointing to where?? >Q: What's the point of advertising a route if it is indeed DOWN? Isn't this >like saying i know that Exit5 is closed but I'm gona keep directing all >motorists to go to Exit 5 anyway? > >Please clarify this for me. > >Elmer
Imagine you have a fairly large OSPF area. If the default route goes down, all the topological databases have to be updated and propagated. While if JUST the default route were involved, the Dijkstra computation will not have to be run, there still will be bandwidth and processor utilization. If there is only one router generating default, and it goes down, the traffic is going to fail anyway. To take your traffic analogy, default-information always is indeed like directing the traffic LEAVING THE AREA to Exit 5, but not otherwise disturbing those cars that don't care about Exit 5. If there's more than one default router, you definitely don't want the always keyword. Now--as far as where it points: "it depends". All it points to is the router generating default. That router may or may not have a default route of its own -- it might be a default-free BGP router as well as an ASBR. It could have a default route of its own that points somewhere outside the AS or area. AFAIK, if the router was default-free, you couldn't use default-information originate without always, because the router would never have a local default to meet the ALWAYS condition. In that case, you'd have to have BGP or a static route specify it, and redistribute that route into OSPF. Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=33810&t=33729 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
