Date: Mon, 24 Mar 2014 15:17:19 +0530 From: soumya panigrahi <soumyapanigrahi@gmail.com> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: Giuseppe Lettieri <giuseppe.lettieri73@gmail.com>, Vincenzo Maffione <v.maffione@gmail.com>, "freebsd-net@freebsd.org" <net@freebsd.org> Subject: Re: Handling Jumbo Packets Message-ID: <CADDTU%2BDYxnEwu%2BtWxfofrykd21JLpc3ps8Y28WwF4tgwXqid5A@mail.gmail.com> In-Reply-To: <CA%2BhQ2%2Bjjihzy1P=s%2BAtSzZfTmL-yLRgCh36331azw2OUTafiaQ@mail.gmail.com> References: <CADDTU%2BCxQdkzktGnvj4SqpG2N-ccN1vNThtQUoue1H00Dkaf5A@mail.gmail.com> <CA%2BhQ2%2Bjjihzy1P=s%2BAtSzZfTmL-yLRgCh36331azw2OUTafiaQ@mail.gmail.com>
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On Mon, Mar 24, 2014 at 2:45 PM, Luigi Rizzo <rizzo@iet.unipi.it> wrote: > > > > On Mon, Mar 24, 2014 at 7:40 AM, soumya panigrahi < > soumyapanigrahi@gmail.com> wrote: > >> Hi, >> >> First of all I would like to thank you all for developing an awesome >> packet capturing framework. >> I have been using it recently and find it very very fast and efficient. >> >> However off late I am trying to capture Jumbo packets on the network for >> the following scenario's but that doesn't seem to be working. >> > > the sysctl tree dev.netmap (on FreeBSD) > or the filesystem > /sys/module/netmap_lin/parameters > (on Linux) > have a number of parameters that control buffer numbers and sizes. > In particular "buf_size" is used to allocate packet buffers and > you can bump it up from 2048 to something larger to accommodate > jumbo buffers. > > Depending on the NIC you may need to do something in the initialization > of the NIC itself to allow sending/receiving frames larger than 1518 bytes, > but I'd just try and see whether it works for you now. > > cheers > luigi > Thanks a lot for the quick response. I will also try to see if we can handle Jumbo frames by tweaking the buf_size parameter on Linux. In addition can you advice if NetMap can de-fragment Jumbo packets that were fragmented as IP packets by intermediate IP device because of MTU size limitation? For example a 9000 Bytes single ethernet frame was fragmented into 1516 Bytes multiple ethernet frames at IP layer. Can netmap re-assemble these fragmented ethernet frames into a single Jumbo frame before passing it the application? If so how? Thanks, Soumya > > > >> Please suggest in its present form is NetMap capable of handling the >> below scenario's w.r.t Jumbo frames? If how do we have to some special >> handling w.r.t to this? >> >> 1) Netmap is receiving un-fragmented Jumbo frame. In this case is NetMap >> capable of passing on the Jumbo packet to the user? >> 2) Netmap receving fragmented Jumbo frames. In this case is NetMap >> capable of reassembling the fragmented packets and deliver the assembled >> packet to the user? >> >> I have been stuck with this issue for some time now. A quick response >> would help a great deal. >> >> Thanks, >> Soumya Panigrahi >> > > > > -- > -----------------------------------------+------------------------------- > Prof. Luigi RIZZO, rizzo@iet.unipi.it . Dip. di Ing. dell'Informazione > http://www.iet.unipi.it/~luigi/ . Universita` di Pisa > TEL +39-050-2211611 . via Diotisalvi 2 > Mobile +39-338-6809875 . 56122 PISA (Italy) > -----------------------------------------+------------------------------- >
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