school netwrok problem, help!!

[Craig T]

Hi

Any help GREATLY appreciated
I have a medium amount of knowledge about networking!! can get my head round
it, but still have a lot 2 learn!
Anyway, the problem
We are a school in the middle of building work, phase 1 is complete and
currently being used by us, with a 100meg ethernet switched network running
around it.
phase 2 is nearing completion and the network will be extended to there
(this MAY be the problem, maybe they are working on adding it and i dont
know about it)
we have one domain server, a linux box running an OS called Navaho. It has
been running since about xmas, currently around 30 pc's on it, all rarely
used as there is no internet access until the building is complete, and we
are going to train the staff all at once! in my room (the temporary ICT
room) i have 2 pc's (used regularly) and 25 toshiba satellite laptops on a
wireless network. these go thru the wireless access point, thru a mini
switch thing onto the main network
these are running windows HOME, but i have used that xteq systems tweaking
xp thing to get it to connect to the domain.
this has worked fine since xmas until last week, altho i do realise that 25
laptops is a lot to have connecting to one wireless access point
i gave a class some image editing to do, taking images off the network about
200k each (did this a few weeks b4, did run slightly sluggishly when all
accessed at once at 1st, but was ok), when i tried it, 7/8 pc's accessed the
images ok, 5/6 could browse thru them slowly but didnt really get anywhere
once cliking on open, and the rest, just did nothing, seemed to hang
tried this a couple of times since, and its been even worse,,
in office progs, the kids would save their work on H: drive (on the server)
adn that was fine , even while the images werent working..
i have my documents set up on the laptops to point to h:\pupil files, and
this used to work ok..
now if u try access my docs, or even my computer on the laptops, it will
just hang there, with the outline of the window, but nothing inside it,
UNLESS you pull out the network card (pcmcia), then it pops up happily but
obv no network access
this USED to work ok, then started like this last week.. but access thru
word etc, was still fine..
now tho, its rare to even be able to browse thru word.
or sometimes, some kids will get in ok, but then when they want to save, get
an error, or open something else, they get all the folders, but with nothing
in them..
the hardwired PCs in my room.. always worked fine until friday
then on friday, sometimes had probs logging in, it couldnt validify the
password sometimes, sometimes it did..
and altho less rare this week, it has still happened from time 2 time..

i think i have given all the information i have there
some points : the pc's/network cards do get knocked about a bit.. they are
kids! as far as i can think, NOTHING has changed or been touched..but
builders do deny everything!! it seems that one/two laptops on their own DO
connect sometimes... i THINK that the laptops still see each other (as
windows network) even when they dont see the navaho (another teacher told me
that! so dont quote me!)

any help/ideas would be greatly appreciated, iether direct to my email or on
here
also can any clarify my understanding here :
1/ if a laptop/network card was 'dodgy/faulty', it could affect the
performance of the laptop network, but not the others because its on a
switch?
2/ if a pc was faulty (or its nic), it wouldnt affect the others as its
switched?
3/ its more likely to be the navaho network problem, as its affected ALL the
laptops at once, and other pc's around?
4/ could it be one or two (or more) machines on the network, pullin the
whole thing down once they are turned on?
5/ wireless access point problem?
6/ we are at least 200/300m from any other building, so i dont think there
will be any interference
7/ server problem?
8/ cabling fault?

i know some of these cross over somewhat, but its starting to confuse me and
do my head in!!

thanks again
Craig

[Anonymous Joe]

"Craig T" <craigtyson@blueyonder.co.uk> wrote in message
news:WPDOa.5414$PX1.43121849@news-text.cableinet.net... Hi Any help GREATLY appreciated I have a medium amount of knowledge about networking!! can get my head
round it, but still have a lot 2 learn! Anyway, the problem We are a school in the middle of building work, phase 1 is complete and currently being used by us, with a 100meg ethernet switched network
running around it. phase 2 is nearing completion and the network will be extended to there (this MAY be the problem, maybe they are working on adding it and i dont know about it) we have one domain server, a linux box running an OS called Navaho. It
has been running since about xmas, currently around 30 pc's on it, all rarely used as there is no internet access until the building is complete, and we are going to train the staff all at once! in my room (the temporary ICT room) i have 2 pc's (used regularly) and 25 toshiba satellite laptops on a wireless network. these go thru the wireless access point, thru a mini switch thing onto the main network these are running windows HOME, but i have used that xteq systems tweaking xp thing to get it to connect to the domain. this has worked fine since xmas until last week, altho i do realise that
25 laptops is a lot to have connecting to one wireless access point i gave a class some image editing to do, taking images off the network
about 200k each (did this a few weeks b4, did run slightly sluggishly when all accessed at once at 1st, but was ok), when i tried it, 7/8 pc's accessed
the images ok, 5/6 could browse thru them slowly but didnt really get anywhere once cliking on open, and the rest, just did nothing, seemed to hang tried this a couple of times since, and its been even worse,, in office progs, the kids would save their work on H: drive (on the
server) adn that was fine , even while the images werent working.. i have my documents set up on the laptops to point to h:\pupil files, and this used to work ok.. now if u try access my docs, or even my computer on the laptops, it will just hang there, with the outline of the window, but nothing inside it, UNLESS you pull out the network card (pcmcia), then it pops up happily but obv no network access this USED to work ok, then started like this last week.. but access thru word etc, was still fine.. now tho, its rare to even be able to browse thru word. or sometimes, some kids will get in ok, but then when they want to save,
get an error, or open something else, they get all the folders, but with
nothing in them.. the hardwired PCs in my room.. always worked fine until friday then on friday, sometimes had probs logging in, it couldnt validify the password sometimes, sometimes it did.. and altho less rare this week, it has still happened from time 2 time.. i think i have given all the information i have there some points : the pc's/network cards do get knocked about a bit.. they are kids! as far as i can think, NOTHING has changed or been touched..but builders do deny everything!! it seems that one/two laptops on their own
DO connect sometimes... i THINK that the laptops still see each other (as windows network) even when they dont see the navaho (another teacher told
me that! so dont quote me!) any help/ideas would be greatly appreciated, iether direct to my email or
on here also can any clarify my understanding here : 1/ if a laptop/network card was 'dodgy/faulty', it could affect the performance of the laptop network, but not the others because its on a switch? 2/ if a pc was faulty (or its nic), it wouldnt affect the others as its switched? 3/ its more likely to be the navaho network problem, as its affected ALL
the laptops at once, and other pc's around? 4/ could it be one or two (or more) machines on the network, pullin the whole thing down once they are turned on? 5/ wireless access point problem? 6/ we are at least 200/300m from any other building, so i dont think there will be any interference 7/ server problem? 8/ cabling fault? i know some of these cross over somewhat, but its starting to confuse me
and do my head in!! thanks again Craig

1 - If a NIC is 'dodgy/faulty' it won't work on that PC, and that single PC
won't have access to anything. It has nothing to do with it being switched.
I think the best analogy is with Christmas lights. There are the kind that
if one light goes out, all of them go, and the type that if one light goes
out, the others stay lit. Well, a network is like the kind that keeps the
others lit. The switch just means that it has 100Mbps to give to each port.
You have a 4 port switch, for example, so each PC gets 100Mbps access, but
the switch can handle up to 400Mbps of activity (although this is simply
unacheivable because of overhead), but if you had a 4 port 10/100 hub, you
have 100Mbps TOTAL, meaning each port gets 25Mbps, but since this isn't
100Mbps, you connect at the 10Mbps speed, meaning the hub will only get up
to 40Mbps of activity. This is all a switch does, gives you the boost from
10Mbps to 100Mbps over a hub. [Switches generally are built into Routers,
so a 4 port router would also give 100Mbps access, but would also include
access to the Internet for everything connected to it {which can be more
than 4 PCs with additional switches/hubs}].

2 - Again, switched has nothing to with it. There's no 'unswitched
networks.' Gives you 100Mbps access through Ethernet cable, and the problem
PC stays to itself.

3 - I think the only way the Linux box could be a problem is if you are
running some ridiculous sort of hardware, like old pre Pentium-III stuff, or
Celerons (at any speed). Your talking about a server here, something with
about 60 PCs on it, maybe more, you're not going to get anywhere by running
some dumb inherited 1996 hardware. It's quite possible that it can handle
30 PCs, but not 60 at once.

4 - A PC can only 'pull down' the network if it is wireless and is accessing
stuff. Being on has nothing to do with it. On is on, but doesn't mean
accessing. If it is accessing stuff, then, yes, that could, but only if it
is wireless. The Ethernet cable'd PCs shouldn't be affected (if they are
then this is a red flag towards your Domain server), but the other wireless
PCs should be.

5 - You do have a problem here, possibly. I've never used wireless, but I
would think that the access point has a total of 11Mbps (might be 22Mbps for
some reason, not sure), but that is shared across all the PCs, like a hub.
Now, if you have 25 PCs accessing stuff at the same time, on an 11Mbps
connection shared evenly, you can expect each PC to have 0.44Mbps access.
That's theoretical, you can probably chop off 25% for overhead, up to 50%
perhaps, so now you have 0.33Mbps access. That doesn't seem so bad, does
it? Yeah, because 1Mbps = 0.125 MB/sec, you have 1/24th of a MegaBYTE
access, which is 42.3KiloBYTES/sec. That is incredibly slow. If you have
25 PCs accessing at the same time, this could only drop down. Odds are the
access point could get confused and start dropping stuff until it drops
everything. But, like I said, I've never used wireless, but this is what
makes sense to me.

6 - Not sure on range, but you should be set, since (I believe), each router
has a slightly different frequency or something so that others can't 'listen
in' (?).

7 - See 3

8 - Unlikely

Good luck ;)

[Craig T]

cheers!!
its sorted now..
i went to the server and read on the LCD display that it had a load of 90%
i thought that didnt sound good, so on the advice of another NG, found out
how to reboot and did!
load is down to aroun 20% and it works!
thanks for all the advice, i am sure it will be useful!!
Craig

[Anonymous Joe]

"CJT" <cheljuba@prodigy.net> wrote in message
news:3F0D93BE.5070001@prodigy.net... Craig T wrote: cheers!! its sorted now.. i went to the server and read on the LCD display that it had a load of
90% i thought that didnt sound good, so on the advice of another NG, found
out how to reboot and did! load is down to aroun 20% and it works! thanks for all the advice, i am sure it will be useful!! Craig I think it's refreshing to hear about a Linux server that is so seldom rebooted that its masters have to figure out how before doing so. If it were Windows, I suspect rebooting would have been one of the first things tried.

Heh.

I might not be good at Linux, but I do know how to shut it down.....and
reboot it.

Anyways, I guess the other stuff still might apply in the future...