[CLUE-Tech] Networking

[skipworthy at realivetech.com]

Russ-

There are a number of things that can cause what you describe: someone
mentioned a duplex mismatch- that's a good guess. If it were windows
machines, I would be looking at NetBIOs vs IP names...(you can get routing
and IP address and lookup issues ) don't know how the ip stack in Fedora is,
it should be a pure stack, but I haven't tested it myself.

Things you didn't mention but could be important: what kind of data are you
moving and how?  for example, an NFS mount can slow things quite a bit.

I assume you have more than one machine on each switch, which is the only
real reason to subdivide that way. I also assume there is just the one wire,
and no other devices between the two switches (both of those could make a
big difference in network performance...)

Assuming all your hardware is healthy as far as you know, and the cables
test good all the way through...
Stuff to try-

1- take machine number two and plug it into switch number one and try the
same tests (download from internet vs between machines.), then swap the
switches and do the same. compare the results.

1b- check ther documentation for the switch and see what it says about that
flashing collision light.

2- Check your firewall settings and so on- again, not sure how Fedora is set
up, but I know that Red Hat starting with 7.0 did some things with default
settings that can alter or impede traffic in unexpected ways.

3- try swapping NICs as a last resort.

interested to hear how this comes out...

Glen

----- Original Message -----
From: "Russell Glissmann" <rglissmann at rfgsolutions.com>
To: "CLUE Tech" <clue-tech at clue.denver.co.us>
Sent: Saturday, January 03, 2004 3:41 PM
Subject: [CLUE-Tech] Networking


> Okay, I've got a personal stumper...
> Two machines, both running Fedora Core 1.  Both on same network,
> although they are on two different switches.  When downloading from the
> Internet, (via cable modem) I get great speeds.  However, if I download
> from machine to machine across my personal network, my speeds are
> terrible (we're talking 6 - 10kb/sec, versus 100 + kb/sec).  This is a
> 100Mb switched lan.  The Internet is plugged into the same switch as my
> first machine, while the second machine is plugged into the second
> switch.  Again, the second machine on the second switch can download
> great from the Internet, which is on the same physical switch as the
> first machine.  I don't understand what is different about downloading
> from the Internet versus my local LAN.  I've noticed that on my second
> switch the collision light is constantly flashing when downloading from
> machine to machine.  That may be a clue, but I have no idea what the
> clue means!
> Thanks for any ideas!
>
> Russ
>
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