[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference 7.286::fddi

Title:FDDI - The Next Generation
Moderator:NETCAD::STEFANI
Created:Thu Apr 27 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2259
Total number of notes:8590

1251.0. "FDDI Void Frames" by ZPOVC::ENGSOON () Tue Mar 01 1994 01:18

    We have a DEMFA on a FDDI ring connected to a Proteon Router.  There
    are messages on the FDDI ring and Proteon has requested the customer
    to check with us regarding void frames.  They would like to know how
    our viod frame are formatted, and any other information on how we
    utilize the void frames.
    
    We sincrerely hope someone will be able to update us, or give us a
    pointer in the documentations.
    
    Thank You,
    
    eng soon
    
    
T.RTitleUserPersonal
Name
DateLines
1251.1CSC32::B_GOODWINMCI Mission Critical Support TeamTue Mar 01 1994 08:563
    You should search this conference. There are many notes talking about
    void frames.
    
1251.2Some info on void framesLEVERS::B_CRONINWed Mar 02 1994 08:5117
    First, void frames are 17 bytes long, which includes FC, DA, SA and FCS
    fields. They can be thought of as frames with no information (i.e. a 
    zero length information field). 
    
    Digital uses voids when the MAC is in "bridge strip" mode, and also
    when running the ring purging algorithm. If you hook up an FDDI
    monitor and see one void at the end of a series of frames, its from 
    a station utilizing bridge stripping. If you see two back to back voids, 
    then they are from the elected purger. 
    
    Proteon's CNX500 also uses void frames when it's MAC chip is in a 
    bridging mode, and also for a latency measuring algorithm (if my
    memory serves me correctly). So, don't assume that all void frames 
    come from Digital FDDI boxes if you see them on the ring.
    
    At the risk of opening a can of worms, is there a problem here, or are
    people just looking for info on void  frames?