From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Mon Jan 12 2004 - 13:40:35 GMT-3
At 10:12 AM -0600 1/12/04, Jaksec, Nick wrote:
>I keep reading and hearing that you shouldn't inject LSA type-5 into your
>OSPF domain if you don't need to. Why not?
>If I inject a route creating a summary or external LSA (whether it be using
>the "network" or "redistributed" command) it is still going to be flooded
>throughout the domain and in other areas as a partial SPF calculation. What
>is the difference between creating a summary versus a external LSA, to me it
>acts the same in other areas. Any response would be appreciated, thanks!
I'm not sure if I'm specifically answering your question, but let me
try. The Dijkstra computation, also known as SPF, is only part of the
OSPF route determination process. It is used only for intra-area
routes (LSA 1 and 2) in a non-backbone area. Its workload goes up
exponentially with the number of links.
Other kinds of routes are added, in a linear manner, depending on the
kind of area.
Regular: SPF(intra-area), linear for external and inter-area
Stubby: SPF(intra-area), linear for inter-area plus default
totally stubby: SPF(intra-area), linear for default
NSSA, not totally stubby: SPF(intra-area), linear for inter-area and
default and
locally imported type 7
NSSA, not totally stubby: SPF(intra-area), linear for default and
locally imported type 7
This archive was generated by hypermail 2.1.4 : Mon Feb 02 2004 - 09:07:43 GMT-3