* Iljitsch van Beijnum: > On 10-okt-04, at 19:46, Florian Weimer wrote: > >> A stateless longest-prefix matching algorithm which costs only a few >> dozen cycles (or very few cache misses) per lookup (even for random >> addresses), provides fast routing table inserts and reasonably >> efficient deletes is not exactly trivial to come up with. A few >> people have been looking for something that is reasonably fast and not >> covered by patents yet, but I'm not aware of any interesting >> discoveries. > > Are you saying that the patricia tree / trie datastructures and/or > their search methods are patented? No, their performance is just less than stellar (at least for the trie algorithms that have been around since the mid-80s). > I was under the impression that this stuff came from the academic > world and as such would be unencumbered by patents. Other routing algorithms come indeed from the academic community, but are covered by patents nevertheless. I can't speak for the U.S., but here in Germany, we are aggressively pushing for more patent output from universities. A few years ago, law was even changed in a way that supervising professors no longer can decide if they want to patent a discovery (sorry, "invention") or not, it's now up to the university. _______________________________________________ Ietf@xxxxxxxx https://www1.ietf.org/mailman/listinfo/ietf