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Conference netcad::hub_mgnt

Title:DEChub/HUBwatch/PROBEwatch CONFERENCE
Notice:Firmware -2, Doc -3, Power -4, HW kits -5, firm load -6&7
Moderator:NETCAD::COLELLADT
Created:Wed Nov 13 1991
Last Modified:Fri Jun 06 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:4455
Total number of notes:16761

2117.0. "DS900EE/EF+Filtering=Perf hit?" by DPDMAI::DAVIES (Mark, SCA Area Network Consultant) Mon Mar 20 1995 01:51

    I have received a voicemail from one of NPG Partners here in Dallas,
    ie, Pioneer Technologies.  The message is from one of their SEs.  He
    says they sold a DECswitch 900EE to a customer that had a clogged up
    ethernet, so they used the 900EF to provide some separation of
    different workgroups.
    
    He says the network is slower now than it was prior to the installtion
    of the DS900EE.
    
    OK, OK, I know this is probably a configuration issue of some sort and
    I will call these guys Monday to see what the "real" configuration is
    and what they actually have done.
    
    My question is around the enabling of filtering on either of the
    DECswitch 900 products.  The Pioneer SE first spoke with some of the
    local Digital MCS/NIS folks and he was told "do not turn on any
    filtering or performance will go down the tubes".
    
    Is the above statement true?  I know the DS900EE can pass 45Kpps, ie,
    max out the attached ethernets.  I know when you turn on an addtional
    feature such as filtering, performance will suffer to some extent.
    
    DO we have any test data to show us what type of performance hit
    turning on flting will do to a DS900?
    
    Thanks,
    
    Mark
    
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2117.1NETCAD::ANILMon Mar 20 1995 13:4622
>  The Pioneer SE first spoke with some of the
>    local Digital MCS/NIS folks and he was told "do not turn on any
>    filtering or performance will go down the tubes".
>    
>    Is the above statement true?  I know the DS900EE can pass 45Kpps, ie,
>    max out the attached ethernets.  I know when you turn on an addtional
>    feature such as filtering, performance will suffer to some extent.
    
    No -- the filtering lookups in the DECswitch are done in a way
    that has no visible impact on performance.  The MCS/NIS people really
    need to check before making statements like that to customers.
    
    Many router vendors do filtering in a sequential manner.. that is,
    filters are added to a list which is then checked sequentially against
    every packet received.  This would cause performance to degrade because
    of the resultant extra processing on each packet.  However the DECswitch
    performs address and protocol filtering lookups on every packet; it
    assumes that these are set up, as opposed to the above which assumes
    they are not.  (The impact to the internal design is that we've thrown
    lookup memory at the problem, to ensure that there is no degradation.)
    
    Anil
2117.2Thanks.DPDMAI::DAVIESMark, SCA Area Network ConsultantMon Mar 20 1995 15:298
    Thank you very much for the response.  This is great news on how we
    implemented filtering on our DECswitches.
    
    This info is the type which needs to be presented to NPG Sales reps and
    SEs so that this can be used in Sales situations.
    
    Mark