Garrett D'Amore writes: > James Carlson wrote: > > Garrett D'Amore writes: > > > >> I think its time someone here took a stand. 9000 bytes is a good size > >> because it is nearly universal, and is sufficient to hold an 8K NFS block. > >> > > > > "Taking a stand" here means being deliberately incompatible with some > > other vendors. > > > > > Only a tiny, tiny minority of vendors who for some reason think it is ok > to support a jumbo frame that is *less* than 9000 bytes. I"ve only seen > one case of that, from a very low end gigabit NIC. (Which uses around a > 7K jumbo frame, I think.) I think those devices could just be > considered "incompatible" with *everyone* else. :-)
No. It's also toxic with those vendors who choose to use something more than 9000 as well (such as, I think, 9180 on Cisco boxes). Your MTU is my MRU, at least when a shared medium is involved. The last survey of this I remember seeing was: http://darkwing.uoregon.edu/~joe/jumbo-clean-gear.html > >> A very few devices support 16K or even higher, but the utility of such > >> large MTUs is probably somewhat limited... even at 10Gb. And the > >> > > > > What if one of these other vendors "takes a stand" on 12K just to > > spite us? Or if the IEEE itself finally decides to set a standard in > > this area and doesn't pick the same value? > > > > The former would be hard, because it would be incompatible with a *lot* > of devices that simply cannot do 12K. They'd be cutting off their nose > to spite their face. The latter seems incredibly unlikely for the same > reason. I agree that 9000 is "likely." I'm not so sure I trust the other vendors involved here enough to say that it's certain. > > I think we're on really shaky ground here. I completely agree with > > having a default jumbogram size, I agree with making it 9000, and I > > agree with making it "hard" to change. I don't agree that we ought to > > make it completely unchangeable just to force the issue. > > > > Okay, I didn't necessarily mean to say there would *no* way to change > it, only that changing it should be something almost never done, and > only then by opening up the hood, so to speak. A choice of some value > other than 9000 is akin to choosing a different inter-packet gap > timing... there may be some unusual application for it, but I'm not sure > it deserves "first class" support (including the same level of QA > coverage!) that the reasonable default gets. Fair enough; it shouldn't be the common path. -- James Carlson, Solaris Networking <[EMAIL PROTECTED]> Sun Microsystems / 1 Network Drive 71.232W Vox +1 781 442 2084 MS UBUR02-212 / Burlington MA 01803-2757 42.496N Fax +1 781 442 1677 _______________________________________________ driver-discuss mailing list driver-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/driver-discuss
