Hey all. I'm going to risk starting a flame war by asking the following: I've been struck by just how much importance Cisco courseware places on route summarization. For example, every student who goes through CCNP-level courseware learns about all the various kinds of summarization - OSPF area summarization, OSPF stubs, EIGRP summarization, etc. etc., and how it reduces the size of the route table, thereby improving router performance by speeding route lookup. 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. Yet, I seem to recall somebody wrote a book (I believe it was Berkowitz) that basically stated that the performance gains associated with reducing the route table via summarization is virtually nil in typical corporate networks, because the real delays were caused simply by the serialization time of sending packets over slow WAN links (T-1 and slower). Plus, with fast-switching and its cousins (optimum switching, MLS, etc.), route lookup isn't done all that often , so there is little lookup delay anyway. And besides, most corporate networks aren't very big - typically less than 100 route entries, so how much lookup delay could there be? 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. Note, I know full well that ISP's/NSP's and very large enterprises (those having on the order of thousands of routes) do indeed benefit substantially from summarization. Of this I have no doubt. What I cannot see is why the typical enterprise would really want to use summarization techniques. Anybody have any thoughts on this? Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=14601&t=14601 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
