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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: Thoughts on increasing MTUs on the internet
> As long as only a small minority of hosts supports >1500-byte MTUs, > there is no incentive for anyone important to start supporting them. > A public server supporting 9000-byte MTUs will be frustrated when it > tries to use them. The overhead (from attempted large packets that > don't make it) and potential trouble will just not be worth it. > This is a little similar to IPv6. > > So I don't see large MTUs coming to the Internet at large soon. They > probably make sense in special cases, maybe for "land-speed records" > and dumb high-speed video equipment, or for server-to-server stuff > such as USENET news. It is *certainly* helpful for USENET news. So perhaps it is time to chuck the whole thing out and start over. There seem to be enough projects out there (cleanslate.stanford.edu, etc) that are looking at just that topic... maybe it is time for a new network design with IPv6, flexible MTU's, etc. The existing MTU 1500 situation made sense on ten megabit ethernet, of course, and at the time, the overall design of the Internet, and the capabilities of the underlying network hardware were such that it wasn't that reasonable or practical to consider trying to make it negotiable. There is no valid technical reason for that situation with modern hardware. The reasons people argue against larger MTU all appear to have to do with hysterical raisins. 1500 was okay at 10 megabits. That could imply 15000 for 100 megabits, and 150000 for 1 gigabit. There probably isn't a huge number of applications for such large MTU's, and certainly universal support is not likely to happen, but we have to realize that the speeds of networks will continue to increase, and in five years we'll probably be running terabit networks everywhere. I could picture 150K MTU's being useful at those speeds. The goal shouldn't really be to simply allow for some fixed higher MTU. If any of these "redesign the Internet" programs succeed, we should be very certain that MTU flexibility is a core feature. ... JG -- Joe Greco - sol.net Network Services - Milwaukee, WI - http://www.sol.net "We call it the 'one bite at the apple' rule. Give me one chance [and] then I won't contact you again." - Direct Marketing Ass'n position on e-mail spam(CNN) With 24 million small businesses in the US alone, that's way too many apples.
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