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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: register.com down sev0?
Hi Vadim! Vadim Antonov wrote: > On Thu, 26 Oct 2006, Tony Li wrote: > >> Further, uRPF is frequently a very inefficient means of implementing BCP >> 38. Consider that you're going to either compare the source address >> against a table of 200,000 routes... > > That would be, well, about 6 memory reads. > > Radix trees are great. They are indeed. If a radix trie is indeed used, you would expect to see about log2(200,000) + 1 = 19 reads on average. >> or against a handful of prefixes that >> you've statically configured in an ACL. > > Which will take much longer with line-by-line sequential matching. Fortunately, modern ACL implementations frequently use TCAMs (1 read) or tree based structures (log2(handful) + 1) as well. As always, the details of a particular implementation are everything. YMMV. Tony |