Computer room networking question

Redwolfe

Hi,

I'm a C++ programmer with fairly little networking knowledge who foolishly volunteered to help set up the computer room in my local primary school. So we have the shiny new computers. Now to network them... this is where my C++ experience is a little less useful.

I've read through the forum and not found anything addressing this particular problem so apologies if it's been answered before.

The school has a broadband connection which feeds into an existing wired LAN. There's a LAN socket in the computer room. I want to avail of this existing setup and just use this one LAN connection to connect all the computer room machines. There are 8 desktops and 6 laptops, but (it's a small school) a lot of the time not all the machines will be in use.

So from my reading a peer-to-peer network inside the room should be sufficient. Is this right?

The desktops have wired LAN cards and the laptops wireless. So what I ideally want is a switch with 8 LAN ports and a built-in wireless access point.

I have found something like this (NETGEAR ProSafe 802.11g Wireless VPN Firewall 8 FVG318) but it seems to expect to take its input from a modem. I don't think it would work in my scenario. Does anyone know if it would in fact work?

The school's relying on my advice here and I don't want to recommend they spend money on something which turns out to be useless. Would it be better to get a simple switch (saw here one for only about 30 euro) and then plug a wireless AP into it?

If I did this, would the internet connection work for everyone out of the box? Do I need to look at installing server software?

I've ordered a computer networking book but it'll take a few days to get here. In the meantime I hope someone can help - it's in a good cause. Thanks!

PS I'm also posting looking for best laser printers. I'm snowed under with too much google info...

AndrewMc

I'm guessing the broadband router also acts as a DHCP server, which means it'll deal with the job of assigning IP addresses to any PC on the LAN? If so, any simple switch joining your PCs to the router should work fine, and the PCs should get direct Internet access without any further effort.

I'd suggest aiming for a 16-port rather than 8-port switch. For starters, you'll use one port connecting it to the socket in the room, and another for the wireless access point, leaving you with just 6. Secondly, you always need more than you expect Try to get a fanless one; when they're not in a comms cabinet the noise is distracting. Ideally you'd want to get the room properly wired with a small wall-mounted cabinet or something, but I'm guessing that's way out of your budget. Bear in mind health and safety, so keep the cables neat, clipped to the wall or tied to the back of the desks, no trip hazards, etc.

I haven't looked into wireless access points recently, but any should do. A spare wireless router if you had one can often be configured to do an equivalent job for your setup.

Having your switch separate from the access point is probably not a bad thing. The switch can be placed somewhere convenient, while the access point can be wall mounted somewhere central to give better signal coverage.

Finally, if you're buying a printer I'd suggest a network-connected one. It's much more convenient than sharing one connected to a PC (which you consequently can't turn off).

Redwolfe

Hi Andrew,

Many thanks for the info. There's a cabinet where the broadband cable comes in to the school containing a Cisco 800 Series router (I don't know which one - have to get the ladder out). I'm sure it must have a DHCP server. I'll plug my laptop in somewhere and check.

There's also an existing switch in the cabinet (Dell PowerConnect 2216) which presumably controls the cables to each of the rooms in the school.

When I have plugged in the new switch in the computer-room (cr) would I be able to leave this existing configuration as is? Do you think I should unplug the cr cable from the existing switch, and plug it directly into the router? I hope there are labels...

Hmm, I have an old wireless router in the cupboard so I'll dig that out and check its AP abilities. With the savings we'd make from using that and a simple switch we might be able to afford a cabinet Probably a good idea in a room full of under-10s...and yes we'll clip the cables neatly to the walls!

Thanks again for the input, it's very reassuring to know we're on the right track.

Knasher

I agree with everything that AndrewMC said, you are definitely much better off getting a separate switch and wireless access point. Most commercial wireless routers have 5 ethernet ports, anything more than that is a unusual and therefore expensive. Just wanted to add that if you are using a wireless router as your ap (they are often advertised as cable routers as apposed to dsl routers which have an integrated dsl modem which you don't need) then you can plug it into one of the 4 ethernet ports on the switch to bridge it to you regular network, but in this case you need to disable the dhcp server on the router as it will interfere with the one already on your network. You can also get ones with an integrated usb port for a usb printer, which may be useful.

AndrewMc

Redwolfe wrote: »

When I have plugged in the new switch in the computer-room (cr) would I be able to leave this existing configuration as is? Do you think I should unplug the cr cable from the existing switch, and plug it directly into the router? I hope there are labels...

Just plug the switch into the existing socket in the cr, it's the least likely to cause trouble.

Redwolfe wrote:

Hmm, I have an old wireless router in the cupboard so I'll dig that out and check its AP abilities.

As Knasher said, disable the wireless router's DHCP and just use a regular Ethernet port to connect to the switch. Once it's set up you can test it by plugging it into the existing network socket in the cr. All going well, you should have the laptops online within minutes

Redwolfe

Thanks both of you. I've now sourced an AP and possibly a free switch. Things are looking up!

Cheers

ressem

By any chance, does the Cisco router connected to the DSL modem have a label mentioning the NCTE, do not touch?
It provides ip addresses for your computers through DHCP with web filtering provided by the department of education / DIT I think.

The info at http://www.ncte.ie/Broadband/ high be of use to you.

By the way, if you look to buy software for a school, you can buy it from a good Microsoft provider for a tiny fraction of the retail cost as they have an agreement with the NCTE.
(e.g. a full legal Office Enterprise education license for €42+vat)

Redwolfe

Hi ressem,

I've been told that the existing setup was installed as part of the broadband-for-schools project, around 2005 I think. The existing system provides web filtering so I'm sure if I looked for the sticker it would be there.

Anyway, we're planning to follow orders and 'not touch' if possible - if it's not broken don't fix it go anywhere near it.

Good to know it has a DHCP server - cheers.

darth_maul

Just be aware that the NCTE only gives a school a block of IP addresses to use, There is a unique block of public IP addresses for each school. The size of the IP address block is determined by the size of the school, with larger schools receiving larger blocks of IP addresses, So you may need to call them to see how many that school has been provided, they may increase them if asked. Also the first 4 IP addresses of this usable IP space have been removed from the DHCP server of the Cisco 871 Router, this is to facilitate network printers, webservers, fileservers etc.

For your job the following would suffice

16 port switch £18.99

Wireless Access point £17.00

Colour laser network printer £130

you would also need patch cables and a reel of cat5 plus rj45 connectors and keystone connectors.

Redwolfe

Hi darth_maul. Thanks for your reply. It gave me such a shock that it's taken me a few days to mull it over.

It's a long time since I got my one and only MCP - 'internetworking with tcp/ip on nt4' - but from what I remember, wouldn't it be more common for internal computer networks to use private IP addresses with (I think) subnet masks? Can you confirm that that's not the case here? Do you mean that each primary-school computer will have an IP address that's unique on the internet? Or am I missing the point?

I did notice that the school's router had an unfamiliar-looking IP - not the standard subnet gateway type address.

I guess I'd better ring the NCTE.

Thanks again for the help and for the advice re switch, AP and printer.

niallb

Hi,
That may hold true if you just use a switch,
but there's no need. Pick any device described as a 'cable router'.
It will have one WAN port to plug into the existing network.
It will get its address as darth_maul described.
It will then by default hand out private addresses to the attached PCs and wireless devices.
Your whole room will only need one "public" IP address,
and even then only if there isn't already such a router plugged in to the NCTE link.
Plug in a laptop directly, and get a DHCP address.
If it's a private one from RFC, you might get away with a dumb switch.
If not, you'll need a router.
The router will almost definitely be simpler to set up unless you need these PCs to talk to PCs in another part of the building.
Make a note if the address the laptop gets from DHCP as there's a small chance of it colliding with the addresses the router assigns, in which case get back to us.

Let me know when you're next actually in the school,
and I'll keep an eye out to help you get a better picture.
Have fun!

darth_maul

Yes you could connect another router and then use private address, but the NCTE don't advise or support this. You could also have issues with network printers etc if you use a mixture of private and public ip addresses.
see the following from their support document

Can I continue to use NAT on my school LAN?
No, many schools that currently have broadband are using Network address translation or NAT. This is because ISPs usually only give one public IP Address per connection and PCs in the school have to use private address space that cannot be routed over the internet (typically in the 192.168.x.x or 10.x.x.x ranges). The router then “translates” these private addresses to the public address(es) supplied by the ISP.
The IP Addresses in use on the Schools Network are publicly routable IP addresses (all starting with 87) and each school is being allocated a range large enough to meet its needs, so there should be no need to use NAT. NAT is not configured on the Cisco 871 and the use of NAT is not supported by either HEAnet or the Service Desk.
Can a school continue to use private IP Addresses on my LAN?
No, PCs that are using private IP address space will not be able to access the Schools Broadband Network connection by using either NAT or a proxy server as neither of these configurations are supported.

NCTE Document

Note this document is old and talks about moving from ordinary broadband to the NCTE school broadband scheme, which all schools are on Now. The schools broadband dsl connection is provided by Imagine, this is the routed through HeaNet and there is also a Heavy duty webfiltering service in there too.

Redwolfe

Cor blimey. I'm glad I asked for help and didn't just try to muddle through.

I'll get on to the NCTE before I buy anything. Will post here when we've made some progress.

MunsterCycling

Glad of this info as was going to start looking at our primary schools network during the summer.

This is f**king typical civil service cr@p, only allow a restricted number of IPs, don't allow them expand in case the school has notions beyond their station and let us decide what can and can't be installed. Another quango for the lads...

Thumbs down

ressem

It's not supported but running through a NAT router/firewall does still work.

It makes monitoring more difficult for the NCTE. And they are public IPs so the number available isn't unlimited.

They will expand the allocated ip address range if you contact them. Best to do so before the summer kicks in though.

Redwolfe

Update... I rang the NCTE and we have enough IP addresses assigned already. We are such a small school that we should have five or ten left over in fact. The NCTE were extremely helpful.

The switch is on its way to us and we've arranged a cupboard to house it. I'll post here on how we get on with installing it. We also have a wireless AP someone had lying around which should suffice.

When looking at printers I found it difficult to locate a cheap laser with cheap replacement toner. The teachers all have printers already so this would just be for the kids. There's a Canon inkjet lying around in the computer room which I'll try to resurrect. There are very cheap generic cartridges available for it. We'll deploy it for a bit and see how the cost of ownership works out. The kids are currently printing nothing - anything would be an improvement.

I'll post an update once we have installed the switch.

darth_maul

Redwolfe wrote: »

Update... I rang the NCTE and we have enough IP addresses assigned already. We are such a small school that we should have five or ten left over in fact. The NCTE were extremely helpful.

The switch is on its way to us and we've arranged a cupboard to house it. I'll post here on how we get on with installing it. We also have a wireless AP someone had lying around which should suffice.

When looking at printers I found it difficult to locate a cheap laser with cheap replacement toner. The teachers all have printers already so this would just be for the kids. There's a Canon inkjet lying around in the computer room which I'll try to resurrect. There are very cheap generic cartridges available for it. We'll deploy it for a bit and see how the cost of ownership works out. The kids are currently printing nothing - anything would be an improvement.

I'll post an update once we have installed the switch.

Would seriously advise getting a shared laser printer rather than individual inkjets, while the laser toner may look dearer, it will last 10 times longer than a inkjet cartridge and doesn't dry out (works out by far cheaper in the long run). Also the cheap inkjets don't last too well in a classroom environment. If the school is using all individual printers they must be spending a fortune on ink.

That samsung laser I posted a link too earlier is fairly reasonable for toner, also the toner is available from viking which most schools use. I have put in 4 of them now and no complaints,