jumbo-frames on the network

mi+mx_at_aldan.algebra.com
Date: 01/29/04

  • Next message: ap296: "RE: Recommendation for "antivirus" software (MTA is qmail)" 
    To: net@FreeBSD.org
Date: Wed, 28 Jan 2004 20:49:02 -0500

    Hello!

    Some newer machines on our FreeBSD/Linux/Windows network have 1000BaseT
    network cards capable of jumbo frames up to 16K (mostly em(4)).

    They are plugged into a big switch, which supports jumbo frames up to 9K
    on each port.

    However, when I try to crank the MTU up on this machines (up to the
    switch's limitation), weird things start happening -- mostly NFS
    problems. I can login to a remote host (wich has MTU of 1500), but it
    will not be able to access the NFS partitions exported by a jumbo-frames
    enhanced box.

    Can different MTUs be mixed on the same wire -- in theory (who is to do
    the fragmentation?) and in practice -- or do we need to isolate these
    machines on a subnet of their own (so that they can keep fast-talking to
    each other) and put something dual-homed between them and the rest of
    the network?

    Do the logins just work because no packet exceeds 1500 anyway?

    Thanks for any advice!

            -mi

    _______________________________________________
    freebsd-isp@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-isp
    To unsubscribe, send any mail to "freebsd-isp-unsubscribe@freebsd.org"

  • Next message: ap296: "RE: Recommendation for "antivirus" software (MTA is qmail)"

    Relevant Pages

    • jumbo-frames on the network
      ... Some newer machines on our FreeBSD/Linux/Windows network have 1000BaseT ... They are plugged into a big switch, which supports jumbo frames up to 9K ... when I try to crank the MTU up on this machines (up to the ...
      (freebsd-net)
    • Re: PROBLEM: Network sky2 Module
      ... They both have this issue with the sky2 network device driver whereby the device would stop working and need to be brought down and back up. ... On the X86_64 kernel on a 100Mbit network, this is a very occasional thing, while on the i386 kernel on a 1Gbit network the device only works for a few minutes at a time. ... If i set the MTU to 7200 then the device seems to stay functional, but then i see long delays when it's talking to 100Mbit devices with standard 1500 MTU that are outside of its LAN segment. ... Yes, I have found that I get far less problem in this area leaving the MTU at 1500, then putting a larger MTU into the routing table for segments, or even just machines, where I know there is direct connectivity. ...
      (Linux-Kernel)
    • Re: Network program locks for MTU 9000
      ... However the exact same test works fine with an MTU of 9000 at 1000baseT. ... MTU 1500 works at both speeds. ... The machines in question have 10/100/1000baseT NICs, and the test code was originally run with two machines directly cabled to each other, where they autonegotiated up to 1000baseT and the Jumbo frames worked fine. ...
      (comp.unix.programmer)
    • Re: Optimising NFS for system files
      ... but few ms at most if network is made properly ... Trying to change mtu, but don't look easy, where can i find the ... mtu n Set the maximum transmission unit of the interface to n, ... Support for Jumbo Frames is provided via the interface MTU setting. ...
      (freebsd-questions)
    • Re: Can find Vista box, cant share folders or printers.
      ... When I click 'Network' on the laptop the ... I've disabled Norton and Windows firewall entirely to make sure that's not ... public folder sharing - on ... start by running the Network Setup Wizard on all machines (see ...
      (microsoft.public.windows.vista.networking_sharing)