Re: Errors on Token Ring line

[Ray Peterson <rpeterso@xxxxxxxxxxxxxx>]

Doug ...



Larry Bolhuis wrote:

>   Hmmm. Generally speaking transfers should be similair in both directions.

I think the difference you are seeing is probably just based on the way things 
are
actually cabled to the MSAU.  Since each port/adapter has to pass the token 
packet,
if the destination is the next adapter it will perform better than if it has to 
be
passed thru three of four intermediate ports.   For example your network might 
look
like this:

    AS1 <------>AS2 <-------->PC1 <-------> PC2 <--------->HP-PRT <----- back 
to AS1

Now transfers from AS2 to PC1 would be much quicker than from PC1 to AS2 via 
PC2,
HP-PRT, AS1 as the token moves around the ring.  (I'm assuming traffic is left 
to
right in above diagram).  The good news is this can be easily improved by 
swapping
out the MSAU for a Token Ring Switch.  We use IBM 8272's which come in 8 and 16 
port
flavors.  We recently bought four used 16 port switches on EBAY for $125/ea.  
You
would have a tough time justifying the $4,500 original price, but with so many 
folks
dumping token ring, you now often find them on EBAY for $100 or less!  And it 
will
make those transfers faster!

The switch will allow you full duplex on adapters which support that.  And it
provides cut-thru switching between ports so PC2 could essentially establish a 
direct
path to AS1 or AS2.  It also provides multiple, concurrent paths among the 
ports on
the switch.  Thus you could have a 32mbs path from PC1 - PC2 and a 16mbs path 
between
AS1 - AS2, compared to a single 16mbs today. Unfortunately, I think the AS/400
adapters are half-duplex only (not 100% sure though!).  Bet Larry knows tho...

HTH

Ray
--
Ray Peterson
WITC - Shell Lake
505 Pine Ridge Drive
Shell Lake  WI  54871
www.witc.tec.wi.us
715 468-2815


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