down sev0?

Hi Vadim!

Vadim Antonov 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.