[SATLUG] OT: Network Question :: cascading switches

[Christian Osso]

my simpletonian analysis:

1) if by "several hundred ft" you mean more than 300, on an ethernet LAN you're going to get some attenuation which can affect throughput, because of retransmission for some frames, especially if it's 350 or more feet.  Is anyone timing out?  or is it just slow.  you seem to be within the 5-4-3-2-1 rule, except maybe for this "several hundred ft" thing you have going there.  

2) you would get collisions only if you are not in full duplex... for example if the switches can't handle FD or you are actually using simple hubs and calling them switches.  Have you tried using a network analyzer to see what's happening?  

3) How many users were complaining?  Could you isolate problems to one or more specific nodes?  How about websites?  Based on what you've said, there's no obvious reason why it should be a LAN problem at all.  It could just be a webserver that everyone is trying to access at the same time (e.g. college registration).



twistedpickles <twistedpickles at gmail.com> wrote:   Last week I was forced to set up about 25 LAN lines throughout a
conference room. I had to cascade switches to get the number of users
and in the locations needed.
The connection was as below:
Internet>Switch>Patch bay>Switch>Switch

In more detail:
Internet Connection > Switch > 6 ft of cable into patch bay > From
patch bay several hundred FT to room > 8 port switch > Line 1 from
Switch to Switch #1, Line 2 to Switch number 2 ...thru line 5 for
switch #5

These switches then sat on a table with 5 LAN connections each for
users to access.

I'm forced to do this often because of the number of computers,
unusual requests for placement and to minimize cabling.

Normally when I've done this in the past I have never ran into any
problems however this one time we ran into some problems that I
contributed to bandwidth while a coworker claimed it was the setup and
the manner in which I set up the switches.

The problem was that someone was complaining of connections speeds to
the Internet below 1 Mbit on a 6 Mbit connection that is shared
between 2 buildings for a few hundred users.

I personally didn't think that the setup would cause 4 Mbits in headroom.
My coworkers and the guy in charge stated "It's network 101, you never
connect switches this way because it causes collisions. I have 5 Mbits
of bandwidth available."

My response would have been "What the @#$% are you talking about,
collisions!?". But because I need my job, I instead picked up the
phone and called a network tech that works with an Internet provider
to get more info. His response was what I expected and he actually
stated that he had to do similar setups.

In the end no real changes were made just accusations, blaiming, and
finger pointing towrds me. Oh he added a wireless access point to one
of the switches. Needless to say Internet speeds fluctuated throughout
the day.

I would just like to hear some thoughts from those of you experienced.


-- 
::twistedPickles:: :
-- 
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