On Sat, Jun 16, 2012 at 5:53 AM, Alexander Hulse <[email protected]> wrote: > I've done some basic research and some (unsuccessful) hacking the on the > driver source for the ag71xx driver and was wondering about baby jumbo frame > support? > > I know that the WNDR37/800's built in switch supports passing jumbo frames, > but the underlying router interfaces do not support large MTU frames. > > However, this: > > http://wiki.mikrotik.com/wiki/Manual:Maximum_Transmission_Unit_on_RouterBoards > > seems to imply that the built-in interfaces ought to support baby jumbo > frames, unless I'm misunderstanding what they are saying. > > As to the "Why?", in the UK, the fibre offering by BT using FTTC uses a PPPoE > modem that can understand PPPoE packets with an MTU 1508, as described in RFC > 4638. > > It was possible using a Netgear WNR834T with the application of some patches > from the pppd git: > > http://git.ozlabs.org/?p=ppp.git;a=commit;h=fd1dcdf758418f040da3ed801ab001b5e46854e7 > http://wiki.aa.net.uk/index.php/FTTC_Modem > > Would this be a useful feature to add (if possible) to CeroWrt so that full > sized frames can be used if the ISP / connection supports it?
I don't quite understand what you want here. The internal ethernet connections on the netgear 3800 are both connected to the switch. The switch is capable of jumbo packets, the ar71xx driver appears to have vlan support only. I'm told it does not have jumbo packet capability, but as to what it's upper limit is, is unknown. As for PPoE with a size 1508... um... one or the other device is going to get in your way here. I presume that 1500 works? You would do better to contact the author of the driver (juhosg) to get your question answered as I'm under the impression he is under the right NDAs. I note that in cerowrt the switch has been configured for jumbo frames even tho the ethernet chip can't do that - because it cuts latency down by a lot to pre-allocate for jumbo frames as the on board buffering on the switch is quite large - in fact, I regard it as too large, even now... > > Alex > _______________________________________________ > Cerowrt-devel mailing list > [email protected] > https://lists.bufferbloat.net/listinfo/cerowrt-devel -- Dave Täht http://www.bufferbloat.net/projects/cerowrt/wiki - "3.3.8-6 is out with fq_codel!" _______________________________________________ Cerowrt-devel mailing list [email protected] https://lists.bufferbloat.net/listinfo/cerowrt-devel
