On Fri, Nov 30, 2018 at 9:57 AM Ron Bonica <rbon...@juniper.net> wrote: > > Guys, > > Does it really matter! Nobody is arguing that applications SHOULD send > packets larger than the MTU in order to improve performance. > > At best, they are arguing that a few outliers (LTP, NFSv2, iPERF) do. > Ron,
I think the question is whether these really are outliers (DNS definitely isn't). For instance, while NFSv2 may have been deprecated, there are other block data protocols that still are in use and presumably could benefit from IP fragmentation (ROCEv2 for example). It's pretty obvious that fragmentation isn't currently feasible on the open Internet, but for other environments, like the datacenter, it may not only be relevant but desirable compared to other solutions. While the draft doesn't deprecate IP fragmentation, it does say "Protocol developers SHOULD NOT develop new protocols that rely on IP fragmentation.". That's a pretty negative and general statement against fragmentation. Without more qualification, I'm not sure getting consensus on this recommendation will be easy. Tom > > Ron > > > > -----Original Message----- > > From: Ole Troan <otr...@employees.org> > > Sent: Friday, November 30, 2018 12:46 PM > > To: Joe Touch <to...@strayalpha.com> > > Cc: Christian Huitema <huit...@huitema.net>; Ron Bonica > > <rbon...@juniper.net>; int-area <int-area@ietf.org> > > Subject: Re: [Int-area] draft-ietf-intarea-frag-fragile-03 > > > > > > > > > On 30 Nov 2018, at 18:33, Joe Touch <to...@strayalpha.com> wrote: > > > > > > > > > > > >> On Nov 30, 2018, at 9:22 AM, Ole Troan <otr...@employees.org> wrote: > > >> > > >> > > >> > > >>> On 30 Nov 2018, at 16:49, Joe Touch <to...@strayalpha.com> wrote: > > >>> > > >>> 1) the lower down the fragmentation occurs, the less overhead is > > >>> needed (i.e., when performance is an issue, it’s even more important > > >>> to fragment as low as possible) > > >> > > >> That sounds like an unfounded myth. > > >> I would think it highly dependent on implementation. > > > > > > Reality: > > > > > > - every layer down you do it avoids a layer of header in-between *at > > > every fragment* ie., IP fragments have only ONE UDP header and ONE > > application header, but app-fragments have multiples of both. > > > > > > Do the math. > > > > Every ipv6 fragment has an additional 8 byte header. But the network might > > not be the bottleneck here, and a few more bytes might not matter. As I > > said it > > depends. > > When it comes to performance making blanket statements is rarely a good > > idea. > > > > Ole > _______________________________________________ > Int-area mailing list > Int-area@ietf.org > https://www.ietf.org/mailman/listinfo/int-area _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area
