Chris Whyte wrote:
> > Additionally, the question arises that if, say, there are 200
> > such interfaces on a given EDGE/ASBR, and one of them
> > flaps...what is worse for the network? Producing a type-5
> > as-external-LSA for a single link state change (which
> > propogates throughout the network essentially unchanged) or
> > producing a type-1 intra-area-LSA which the ABR(s) still have
> > to analyze in order to find the (1) network out of the 200
> > whose state has changed.
> >
>
> Oh... I bet you're frustrated. 4 e-mails later and the question hasn't
> even been addressesd by anyone, let alone me. Well, I feel obligated to
> attempt now that I understand what you're asking.
It was more a rhetorical than anything else, as it depends upon the implementation, but it's one worth asking since every network is different.
> So, I imagine that it might vary depending on the implementation as I've
> seen some ugly ones when it comes to not doing incrementals when they
> could. If memory serves, neither option should require a full Dijkstra
> at any router in the network since the flapping network is a stub.
> However, I still think the latter is more beneficial since the former
> has some, though possibly minor, impact on the *entire* network. The
> impact of the latter can be limited to the local area as long as it's
> being summarized at the abr. I've always been a fan of isolating the
> visibility of any failure whenever possible. Plus the other benefits
> just make it the cleanest solution in my mind.
Again, this is presuming summarizations which may not exist in a legacy environment and may not be possible to implement in that environment.
> In the many discussions I've had with developers in the past, analyzing
> a router-lsa with lots of interfaces has never been mentioned to me as
> an intensive process or just something to be concerned about in general.
I was searching for a comparative, and on the whole I am inclined to think that the impact could potentially be worse (however negligible it might be) in a legacy environment which it is not possible to summarize.
If a person is running a 2501 with thousands of routes (that does happen) that person might be inclined to drop as many CPU cycles as possible.
In the end, it's a toss-up depending upon your implementation.
-J
This archive was generated by hypermail 2b29 : Sun Aug 04 2002 - 04:12:41 EDT