Conference netcad::hub_mgnt

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Front           |   |   |             |   |   |     |   |   |     |   |   |
      +-------+-3-+-4-+-5-+ +-------+-3-+-4-+-5-+ +-5-+-6-+-7-+ +-5-+-6-+-7-+
      |  PORTswitch900TP  | |  PORTSwitch900TP  | |PEswitch   | |PEswitch   |
      |   |   |   |   |   | |   |   |   |   |   | |     900TX | |     900TX |
      |Gr1|Gr2|Gr3|Gr4|Gr5| |Gr6|Gr7|Gr8|Gr9|GrA| |           | |           |
      |   |   |   |   |   | |   |   |   |   |   | |           | |           |
      +-1-+-2-+-----------+ +-1-+-2-+-----------+ +-1-+-3-+-4-+ +-1-+-3-+-4-+
Back    |   |                 |   |                 |   |   |     |   |   |
[FDDI]==|===|=================|===|=================+===|===|=====+===|===|===
        |   |                 |   |                     |   |         |   |
[LAN1]--+---|-----------------|---|---------------------+---|---------|---|---
            |                 |   |                         |         |   |
[LAN2]------+-----------------|---|-------------------------+---------|---|---
                              |   |                                   |   |
[LAN3]------------------------+---|-----------------------------------+---|---
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[LAN4]----------------------------+---------------------------------------+---


  1.Each PEswitch900TX connect 900MS Multi Channel(FDDI).

  2.Each PORTswitch900TP separate 5 group.
    (Gr1,Gr2,Gr3,Gr4,Gr5,Gr6,Gr7,Gr8,Gr9,GrA=Gr10)

  3.Each PORTswitch900TP Gr1,Gr2,Gr6,Gr7 connect 900MS Multi Channel. 
    LAN1,LAN2,LAN3,LAN4

  4.Each PORTswitch900TP Gr3,Gr4,Gr5,Gr8,Gr9,GrA connect PEswitch900TP Front 
    10Base-T port.
    Not connect Multi Channel.

  My Customer want 10 Group LAN in the DEChub900MS.
  *** This Configration is OK ?

    
    A point to note about Novell IPX is that it is a Request-Response
    protocol where each request is explicitly acknowledged by a response.
    It does not use any sliding window mechanism to better utilize the
    network bandwidth. When a client boots and establishes contact with the
    server, in the order of 10000 or more frames are exchanged and
    these packets are large 1000+ bytes. In your configuration these frames
    have to traverse 2 ethernets and an FDDi ring. In the case of ethernets
    a 1000+ byte frame would have ~1 msec of transmission delay. The FDDI
    transmission delay would be 1/10th of that, but you have to consider
    how busy the ring is because that relates to the time it takes to grab
    the token and transmit. The switches themeselves have some latency to
    translate and forward these frames, but that is negligible compared to
    these other time factors. Another factor that could play into this, is
    that Novell's retry timer is dynamically adjusted based on the
    roundtrip transfer times of packets. It may start out very small, thus
    causing more retries before it converges to a retry interval that is
    suitable for the topology. If you add the numbers up for the case of
    10000 frames you would see an additional time of 10+ seconds to the
    case where the client and server are on the same ethernet.
    
    If the purpose of separating the servers to another ethernet is to
    provide them with dedicated bandwidth, then putting them on the same
    switch in different ports would be better in terms of performance. You
    would not have to contend with the packet translation and FDDI
    transmission delays. The other alternative is to have the servers on
    FDDI, this would increase the packet delays a little bit, but would
    provide 10 times the bandwidth.
    
    Hope this helps,
    Krishna

Ask the customer to try enabling the new Novell 'packet burst'
software feature. This provides a sliding window type scheme
to the upper level Netware protocol allowing multiple transmits
prior to receiving an acknowledgement. This should improve things
if the slow down is a result of added latency.

This software was initially an optional product/kit but I think
it is part of some recent version of the Netware product.

Dave,

            <<< NETCAD::KALI$USER3:[NOTES$LIBRARY]HUB_MGNT.NOTE;1 >>>
                   -< DEChub/HUBwatch/PROBEwatch CONFERENCE >-
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Note 2526.0                  IP is better than IPX!                   No replies
SNOFS1::63496::SYSTEM                                20 lines  16-JUL-1995 20:48
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    re .2/.3
    
    Thanks for your help!
    
    Customer also tested with IP (using ftp) the same PC but to AXP running
    OSF/1 V3.2, the performance using Ethernet-Ethernet is still better
    than Ethernet-FDDI-Ethernet (via two DS900EFs) and is about 10-15%.
    This gives me an idea that IPX is not so good even in LAN when compared
    to IP. We will try to look into their Netware configuration to see
    whether we can do some tuning. Some questions need clarification:
    
    1) What is the difference between using Ethernet Frame and 802.3 frames
    in Netware? 
    
    2) When DS900EF translate ethernet frames to FDDI, is there any
    difference between Ethernet II and 802.2/3 frame?
    
    
    thanks again for help/idea.
    Andrew Chiu - Network services sydney