> On 12/22/2011 10:13 AM, Francois Labreque wrote:

>>> OK, So I am still on the hunt for the network delays I am seeing - so
>>> some questions about network throughput.
>>>
>>> My Hardware
>>>
>>> Windows Domain Server - (1) 1 GB ethernet
>>>
>>
>> Make sure the server NICs are hard-coded for 1 Gbps Full-duplex.
>> Gigabitethernet left in auto-detect mode can lead to funky things...
>>
>> Make sure the switch ports facing the servers also have their speed and
>> duplex hardcoded, if possible.
>>
>
> I will look into this.
>
>>> File Server - (2) 1GB ethernet (bonded to share load into the same
>>> switch)
>>>
>>
>> How? Depending on the way it's set up, it can cause major problems with
>> the switch. Disconnect one of the patch cords and see if performance
>> improves. If it does, you had a loop between the two switch ports, and
>> the two NICs in your server. Either reconfigure your NICs to use
>> fail-over, or make sure "spanning-tree" is enabled on the switch ports
>> facing the server. Keep in mind that by doing that you will lose your
>> 2Gbps aggregation speed and the second NIC will only be there to provide
>> a host-stanby.
>>
>
> Hmmm - something to look at. I'll try to run a test in the near future.
> It has run like this for 4 years without a visible issue - but that
> could be due to a light load.
>
>
>>> Patch panel and patch cords are CAT5e
>>>
>>
>> Length? CAT5e specification says that desks-side patch cords must not be
>> longer than 3m (10ft), and that switch-side patch cords can not be
>> longer than 7m (25ft), while the total length of the premises cabling
>> (in the wall) must not exceed 90m (300ft). See below to know how to do
>> this.
>>
>
> desk-side - 5-10 ft typical - a very few longer - < 15 ft
> switch-side - < 3 ft
> in wall - < 100 ft (building is 100' long and net room is in the middle.
>

Do not assume anything.  Cabling conduits sometimes take funky routes 
around (or into... but that's a big fire hazard!) ventilation ducts, 
plumbing, elevator shafts, etc...  I've seen cables strung as tight as 
piano wire, I've seen bundles of cables thrown under the floors because 
the cabling guys were too lazy to cut them to the proper lengths, I've 
seen attack ship fire off the shoulder of Orion...

>>> In Wall wiring is combination of CAT5 and CAT5e
>>>
>>
>> Do you have lots of internediary patch panel connections (e.g.: desk to
>> wiring closet. Wiring closet to server room main wall. Server room wall
>> to rack patch panel)
>>
>
> server patch directly switch
> switch patch to panel
> panel run to wall outlet
> wall outlet patch to computer
>
>
>>> Switch is DELL PowerConnect 2724 running in a non-managed mode
>>>
>>
>> According to TFM (which you should R), there are cable-testing functions
>> in the switch. Check to see if you have faulty cabling, exceed the
>> length of the standards, or if the premises cabling can really sustain
>> 1Gbps. If not, downgrade the user ports to 100 Mbps.
>>
>
> Working on RTFM - as time allows.
> Just set the switch to 'managed mode' while nobody was in the office.
> Now to figure out how to 'use' it.
>
>
>
>>> about 10 users on the network
>>>
>>
>> Check, if possible, for rogue user activity (Is anyone running a
>> streaming app? Is anyone acting as a Counterstrike server? Does anyone
>> have NetBEUI turned on by mistake? etc...)
>>
>
> We do have people running streaming music and video - and even a small
> minecraft server for local use (guys like to lunch it)
>
> My thought is that the bandwidth that these things use is small enough
> as to not impact usability. We have never seen things like this impact
> the network before.
>

Things have certainly improved since Doom 1.1 wrecked havoc on company 
LANs in the early 90s, but it's always a good think to know what's out 
there and be ready to limit extra-curricular activies, if it's 
preventing people from working.

>
> Our pipe to the internet is 50/10 and is pretty consistent - but that
> should not overly impact server-client speeds in out office - should it?
>

Unless someone has gotten access to your server and is running a proxy 
from it, no.

>
>
>>>
>>> What slowdowns might this kind of setup cause?
>>>
>>
>> Apart from the risk of having a spanning-tree loop between the switch
>> and the dual-homed server, there's nothing inherently bad about this
>> setup. By default it should run fine.
>>
>
> We have been running the network like this since 2007 without noticing
> any problems. But with a few extra guys in the office it sounds like it
> could cause some latent problems to crop up.
>
> The spanning-tree loop sounds like something to look into. I'll run some
> tests with disconnecting a port to see if that may be the cause of the
> problem as well as using the managed features of the switch to run down
> some issues.
>
>
> Thanks
>


-- 
/*Francois Labreque*/#local a=x+y;#local b=x+a;#local c=a+b;#macro P(F//
/*    flabreque    */L)polygon{5,F,F+z,L+z,L,F pigment{rgb 9}}#end union
/*        @        */{P(0,a)P(a,b)P(b,c)P(2*a,2*b)P(2*b,b+c)P(b+c,<2,3>)
/*   gmail.com     */}camera{orthographic location<6,1.25,-6>look_at a }

Post a reply to this message