chris@yarra.oz.au (Chris Jankowski) (10/26/90)
I encountered an amazing problem on a thinwire Ethernet segment.
I have no idea what may be causing it.
Can somebody provide a plausible explanation?
bulk-head on the wall with 2 T connectors - A and B
|
v
Thin Ethernet segment A B
---------------------------# #------------------------
| |
~2m cable | | ~2m cable
--------------| |-------------------
| |
# <<< T connector T connector >>> # <<< a PC with an Ethernet
| | card is connected here
--------------------------------------
~3m cable
The problem is that if I swap the two cables connected to A and B connectors
the PC ceases to work or works unreliably.
No other station on this segment is affected.
This should not be the case as the connection should in no way be dependent
on what is connected where and in what order provided there is continuity,
proper terminations, less then maximum total cable length and number of
breaks (T pieces and barrel connectors).
I checked all of the above as well as having a cabling contractor to
recertify all segments.
My main worry is that I do not understand the mechanism of this failure.
And that means that I cannot trust the network cabling plant and therefore
anything which happens there. This also undermines the whole methodology
of problem resolution in the higher layer protocols where I normally work.
Your help will be much appreciated.
-m------- Chris Jankowski - Senior Systems Engineer chris@yarra.oz.au
---mmm----- Pyramid Technology Corporation Pty. Ltd. fax +61 3 820 0536
-----mmmmm--- 11th Floor, 14 Queens Road tel. +61 3 820 0711
-------mmmmmmm- Melbourne, Victoria, 3004 AUSTRALIA (03) 820 0711
micron, n.- a unit of length of one milionth of a meter,
worth $2,000,000,000 since the fault in the Hubble space telescope
mirror has been identified.