I know there have been loads of VOIP threads already, I have read the vast majority of them!
It is something we really need to get done here, just trying to consider our options. Quick overview of our school & network:
- 3 sites, each connected with 100Mb fibre and VPN between each. External access is 10Mb EFM line.
- Old (around 10 years?) internal phone system in senior department, 6-8 external numbers, as for lines, not sure. Can't find an ISDN box or anything, not sure what comes in.
- Approx 30 extensions at this site
- Other 2 sites just have 3-5 standard phone lines per site
First of all, hosted or internal? Everything I have heard so far says avoid hosted unless it's only a few users, which I have no problem with. Opinions?
Should I be going for total VOIP including SIP trunks or just internal and keep analogue lines? (I'm thinking keep analogue lines, for now at least)
Finally, what is a ballpark figure I should be looking at for a controller, and per handset?
Also, I was thinking perhaps I could start learning Asterisk/FreePBX, buy a couple of cheap IP phones and get a whole test setup and potenially do it myself. Or (bearing in mind my limited VOIP knowledge, which will improve) should I be looking at purely off the shelf solutions?
Finally, with the links between schools, is it realistic to have the VOIP traffic passing over the VPN or could that be problematic?
Thanks. Been playing with FreePBX...a lot to learn but thats all good. If I was to use software SIP phones while learning, would it be a realistic test for QOS on switches or not?
Also, been trying to get to grips with our current phone system....I can't work out where any lines come in! The only box we have is an old BT NTE52B 'Megastream' box, which has an ethernet cable going to god knows where in the phone patch panel. But from Googling, this just seems to be an old point to point ethernet link. So why is is plugged into our phone system?
Sounds to me as though your incoming ISDN (if its ISDN) connects into the BT box which then transmits the ISDN over ethernet into the phone system - although from googling I've got one in my server room and not a clue what it was connected to!
With regards to the QOS probably not as you would want to segregat the traffic on VLans to apply the qos but it won't work.
Ah ok, possibly then. I think I need to get someone from the maintenance company in and show me whats what with the old system. Its a bulky thing thats for sure, and the rats nest of extension wiring just makes me go
Fair point about QOS. So if I was to buy a couple of cheap SIP phones and then setup a VLAN on one of our switches for them it would be a good start for learning it?
The general consensus from those I've spoken to about QoS is to only use it if you are having problems without it, it can be a real PITA to configure and debug. Try it without first.
Yup - on our HP switches there is an option for Voice (not sure what it does!) - we havn't done the QOS thing yet but have 900 clients and 80 handsets connected over the entire LAN (across multiple vlans) and its working brilliantly so far!
The 'voice' vlan setting on procurves are to allow you to run two vlans (your VOIP vlan, and a data VLAN) to a port with a physical VOIP phone attached. Typically because the VOIP phone has a passthru Ethernet port for a PC or similar device or because it needs to TFTP boot off your data network as well as access your VOIP VLAN..
Cisco switches have a similar feature but they call it 'smartport'
Admittedly you can get the same results from 802.1Q tagging. I presume it's just a hangover from the depths of VOIP history or some vendor specific crud.
Last edited by Geoff; 20th April 2012 at 01:36 PM.