Re: Errors on Token Ring line

Dougm
 
> Where can I find documentation on the interrelationships of the max
> frame size of the LIND, the MTU of the interface, and all the rest of
<snip>
Good question.  I have gleaned bits from everywhere and nowhere in particular.

> Last weekend I was experimenting on trying to increase the throughput
> of my local TR network (no routers) and had mixed success.  I was able
> to boost transfers from my 400 to the PC to run at about 950K/sec, but
> can only achieve half of that when transferring from my PC to the 400.

  Hmmm. Generally speaking transfers should be similair in both directions.  
Some
factors involved besides MTU, LAN speed, etc are that the AS/400 may be doing
ASCII EBCDIC tanslations, and other work depending on where the file is stored 
on
the AS/400.

> Obviously the PC's max frame size of 8156 could explain why I get much
> lower throughput on PC to 400 then 400 to PC.

  No not really.  If the 400 sends 16K packets to the PC and it can't handle 
them
then you get nothing!  Likely the two have negotiated 8K packets both ways.

> But when I set the PC
> to 16388 or 16393, I can't even ping the 400 let alone transfer
> anything.  The PC driver lets me specify the TX frame size but not the
> MTU, so I had figured 16393 would be the value to use.  The driver
> lets me enter any arbitrary value I want (not just select from a list
> of values).
 
  It is likely there is a memory shortage or other configuration on the PC T/R
adaptor.  Once set that large the PC driver probably isn't connecting to the
network correctly at all.
 
> I also tried setting the 400 interface type of service to *MAXTHRPUT
> instead of *NORMAL, but again couldn't ping between the systems until
> I went back to *NORMAL.

  Common misconception here.  That is an attribute you assign on the AS/400 to
tell it which lines should be used for what type of traffic.  When you set the
line that way only traffice attempting to find *MAXTHRPUT lines will travel
across it!  This does NOT change the line to run any faster!

> Any ideas?  I'd like to get my upload speeds to match the 950K/sec I
> can now get with downloads.  There are only 5 devices on my network:
> two AS/400's, two PC's, and a HP JetDirect.

  Well, I agree that faster is better!  Chances are though that with only 5
devices on the net its utilization is likely under 2% average. Thus the bigger
packets (8K to 16K) would only yeild very marginal improvements.

  Sorry I can't be more help!

 - Larry

-- 
Larry Bolhuis         |         What if it's True?
Arbor Solutions, Inc  |
(616) 451-2500        |  
(616) 451-2571 -fax   | 
lbolhui@ibm.net       |
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