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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

1418.0. "Packet Format " by RDGENG::BICKNELL () Tue Aug 09 1994 07:12

    Hi,
    
      Could someone help with the question below ?
    
      I have a Novell PC which is using the Ethernet_II frame format 
      (Same format as Phase IV Decnet) on a LAN connected to the Ethernet
      port of a 620 Bridge.
    
      What type of format does the packet take once it has passed through
      the bridge & is now traveling on the FDDI .
    
    
     Regards,
    
      Ian Bicknell
T.RTitleUserPersonal
Name		DateLines
1418.1ETHERNET_II <==> FDDI_SNAP4371::STEFANIHave the # for the Mars Observer?Tue Aug 09 1994 14:5635
    Ian,
    
    >>  I have a Novell PC which is using the Ethernet_II frame format 
    >>  (Same format as Phase IV Decnet) on a LAN connected to the Ethernet
    >>  port of a 620 Bridge.
    >>
    >>  What type of format does the packet take once it has passed through
    >>  the bridge & is now traveling on the FDDI .
    
    [Blanket assumption that you're talking IPX]
    
    The Novell ETHERNET_II IPX frame will look like this:
    
    	DA-SA-81-37-FF-FF-IPX_len-...
    
    where DA and SA are the 6-byte destination and source addresses, 81-37
    is the two-byte protocol ID for IPX, FF-FF is the IPX checksumming
    field (if turned off), and IPX_len-... is the rest of the IPX
    routing and data information.
    
    Over our translating bridges (all of them) this turns into a standard
    Novell FDDI_SNAP IPX frame which looks like this:
    
        FC-DA-SA-AA-AA-03-00-00-00-81-37-FF-FF-IPX_len-...
    
    where the bridge added the FC byte and SNAP SAP (AA-AA-03-00-00-00). 
    Going back over the bridge, we strip the FC byte and SNAP SAP to
    translate it back to ETHERNET_II.
    
    This translation works quite nicely, I might add.  We've been running a
    Novell FDDI-Ethernet bridged environment here at King St. for a few
    years now.
    
       - Larry
1418.2RDGENG::BICKNELLThu Aug 11 1994 04:448
    Thanks Larry ,
    
     The information has made the network design for a Novell network in
     France a lot simpler .
    
    Thanks again.
    
    Ian
1418.3LEVERS::STEFANIHave the # for the Mars Observer?Thu Aug 11 1994 10:1713
    >> The information has made the network design for a Novell network in
    >> France a lot simpler .
    
    Anything to make the world a better place.  :-)
    
    I failed to mention that this frame type combination is also used to
    support Novell's TCP/IP protocol modules (TCPIP.NLM and TCPIP.EXE), so if
    your customer is adding TCP/IP or NFS support anytime soon, they should
    be all set driver/frame type configuration-wise.
    
    Good luck and sell lots of adapters.
    
       - Larry