--- nrf wrote: > I thought somebody was going to talk about masking > instabilities. But then > that begs the question - in a typical enterprise > network (therefore a small > one of 100 routes or less), if you are suffering > from routing instabilities, > isn't your time better spent to try to figure out > why your routes are so > unstable and then remedying it rather than engaging > in summarization in > order to mask the instability. There is no question begged. You make it sound like summarization is being used as a method to deal with a crisis. It is most emphatically not that. It is a network design principle/technique that can (among other things) reduce the impact of routing instability and isolate it so that you can deal with it effectively and quickly. Routing instability can be caused by hardware failure, not just configuration problems. No one goes around summarizing routes in the middle of an outage. Summarization is considered while designing and implementing the topology you have decided upon. Sound network designs should make sense, not just merely work because you can throw CPU/memory at them. Hierarchy simplifies understanding the network topology and actually aids in the sensible deployment of address space. What you are advocating is merely sloppy thinking that is excused only by its small scale: "Close enough for government work." What happens if that enterprise succeeds and grows into a multinational with its own AS and countless branch offices. Heaven help you if you are the hapless engineer that has to renumber and redesign that klugey network that was built solely on expediency. Geoff. > Like I said previously, I completely agree that > summarization is indeed very > useful in large networks like NSP/ISP's or large > enterprises (1000+ routes), > for many reasons (better lookup performance, masking > truly becomes useful > because you can't be expected to fix all your flaky > links in a huge network, > etc.). But I would like to understand if > summarization can be useful in a > typical enterprise network ( wrote in message > [EMAIL PROTECTED]">news:[EMAIL PROTECTED]... > > Performance gains are only a small part of the > > picture... what is more important is enforcing a > > proper hierarchical addressing scheme that > conceals > > routing instabilities from the network as a whole, > and > > lessens the amount of routing update traffic > > propagated across the entire network. > > > > It's gotten to the point > > > that Cisco-trained > > > personnel treat summarization like the holy > grail, > > > and they go around trying > > > to use summarization techniques wherever they > can. > > > > A network always benefits from the consistent > > application of design goals. Summarization scales > > well because of the architecture which flows from > a > > properly addressed network. I can't think of > anyone > > outside of an SP network concerned with global > routing > > table bloat that ever equates the benefits of > > summarization in terms of increased routing table > > lookup efficiency. The benefit is that flapping > > routes and their attendant update traffic are > confined > > to a small manageable area. Not only does this > > preserve bw but it greatly aids in network > management > > by narrowing the scope of the network that you > need to > > troubleshoot. > > > > So, when I weigh > > > the cons of suboptimal routing as well as the > > > possibility of > > > misconfiguration, I find it difficult to see why > the > > > typical enterprise > > > would ever really want to do summarization, as > the > > > gains are miniscule at > > > best. > > > > If the network architects can't properly > summarize, > > there are bound to be bigger problems than what > that > > particular misconfiguration will bring. We are > not > > talking rocket science here, it is simple binary > math. > > > > Best regards, > > > > Geoff Zinderdine > > CCNP MCP2K CCA > > MTS Communications > > > > __________________________________________________ > > Do You Yahoo!? > > Make international calls for as low as $.04/minute > with Yahoo! Messenger > > http://phonecard.yahoo.com/ [EMAIL PROTECTED] __________________________________________________ Do You Yahoo!? Make international calls for as low as $.04/minute with Yahoo! Messenger http://phonecard.yahoo.com/ Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=14622&t=14622 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
