MTU, Jumbo Frame Settings

Discussion in 'DIRECTV - Coax Networking (private)' started by Spanky_Partain, Aug 26, 2009.

  1. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Has or does anyone use non-standard MTU sizes in their environment that may mess with the DECA networking?

    Should I do some different settings and see if that is a possible bug or is a standard packet size the only thing supported?
     
  2. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Ok, I guess I need to mess around and try setting up some different MTU sizes and see if the DECA units adjust accordingly.
     
  3. dettxw

    dettxw MRVing

    4,117
    21
    Nov 21, 2007
    Choctaw, OK
    I don't think that my WRT600N supports jumbo frames?

    edit - Hmm...the above info was from a pre-production unit review. Looks like there is an MTU setting, but no high limit given, only a recommended 1200-1500 if manual is used.
     
  4. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Yea, you probably will not want to incorporate the home router to do any large MTU settings anyway. The connections to each port and the hardware, like the PC, will also need to be changed to verify the MTU size change.
     
  5. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Sounds like a fun test and this is what I am going to try this weekend.

    It will take some different equipment than what is in the normal house.

    SETUP:
    HP Procurve 6108 Switch
    Set MTU to 9000 on switch port to PC 1
    Set MTU to 9000 on switch port to PC 2

    PC1
    Set MTU size on NIC to 9000 on PC 1

    PC2
    Set MTU size on NIC to 9000 on PC 2

    Plug DECA uplink into default set switch port

    TEST
    Check connection and verify jumbo packets are being used between the PC's via switch stats
    Open a Music, Photo, Movie session from one of the DVR's in the cloud
    Start a picture show from one of the PC's, verify window size in use and pictures can be seen

    Do the same with music and also a movie via PlayOn

    RESULT
    There may be a reason why this may not work.
    A. If it is UDP traffic there wil not be any negotiation between the two connections advertising window size. If this is the case the mismatched window size will not allow communication. The packets will be dropped.
     
  6. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    I can't believe my Procurve does not have a MTU setting! :(

    Now I got to carry the big/heavy one home!
     
  7. Tom Robertson

    Tom Robertson Lifetime Achiever DBSTalk Club

    21,331
    247
    Nov 15, 2005
    Any chance the switches automatically handle jumbo packets?
     
  8. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Not the Procurve 6108 model. I have a selection I can use, but they do start getting a little bulky!
     
  9. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Just to let others know, this is a Gb only test and it is a pretty unusual circumstance/environment that the DECA and/or DVR would be subjected to this. However, in large commercial media areas it could be possible but even then unlikely.

    I have a Cisco Catalyst 2960 that I am going to use for this trial.

    EDIT
    However, it would be good information to pass along so Directv could put a line in there about supported MTU size, just in case.
     
  10. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

    42,739
    361
    Dec 9, 2006
    Can I get fries with that Jumbo please? :lol:

    [shoe on other foot] I'm getting an idea of what my RF posts look like to some. :lol:
     
  11. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Ok, so it is getting close to lunch time and my brain kind of stops until 1:00pm CST, RF?
     
  12. veryoldschool

    veryoldschool Lifetime Achiever Staff Member Super Moderator DBSTalk Club

    42,739
    361
    Dec 9, 2006
    RF = Radio Frequency
    [aka the domain that isn't IP based]
     
  13. Spanky_Partain

    Spanky_Partain Active Member

    5,500
    0
    Dec 7, 2006
    Yea, now that I have had lunch, it makes perfect since.... :lol:
     

Share This Page

spam firewall