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Wireless Networks Thread, VOiP in Schools in Technical; Originally Posted by localzuk Indeed. My suggestion for VOIP is a) make sure you have QoS enabled for it and ...
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    Quote Originally Posted by localzuk View Post
    Indeed. My suggestion for VOIP is a) make sure you have QoS enabled for it and b) if internal, subnet your network and put VOIP into its own VLAN.
    Interestingly, this is something I haven't yet got round to doing... I plan to VLAN my network this year and QoS, currently we're not noticing any quality issues (only really hit by hardware issues with phones - like the sockets for the handsets or cables to handsets dieing off), and the thing that surprised me more, over our 10Mb external connection for the trunks we don't get much if any jitter (no worse that any other phone system I've heard). Now up to 100Mb external and no issues reported.

    Cheers

    Will

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    Quote Originally Posted by Willott View Post
    As for Gradwell, they're usually at the forefront of VoIP in the UK - their MD was part of the team that worked on 999 integration system for VoIP
    What do we need to do as regards 999 calls and VoIP systems? Does anyone know if schools are required to have a minimum service level for 999-capable phones in case of an emergency - can we just have one 999-capable phone on the front desk, or do we need more? Will a standard VoIP handset be able to make 999 calls? What happens if there's a power outage - do we need to have phones or PoE switches attached to UPSes capable of running the handsets for a given amount of time?

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    localzuk's Avatar
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    Quote Originally Posted by dhicks View Post
    What do we need to do as regards 999 calls and VoIP systems? Does anyone know if schools are required to have a minimum service level for 999-capable phones in case of an emergency - can we just have one 999-capable phone on the front desk, or do we need more? Will a standard VoIP handset be able to make 999 calls? What happens if there's a power outage - do we need to have phones or PoE switches attached to UPSes capable of running the handsets for a given amount of time?
    999 can be dialled via VOIP just fine. We currently keep a normal phone in a cupboard just in case we lose the phone system, to plug into our fax line. Else we also have a school mobile etc...

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    dhicks (15th March 2011)

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    Quote Originally Posted by Willott View Post
    How's you're current PBX supplied
    That's the problem, we're not that sure. I'll try and have a rummage at some point, but the boxes are under the desk in the main reception lobby and people are sat there all day.

    Do the boxes have circuitry in or are they just wire to wire connections? What make is your current PBX, are there any digital handsets?
    Not sure about the inside of those beige boxes, or what the make of the current PBX is. Our current handsets are Panasonic KX-T7420 handsets, which have "Digital Super Hybrid System" written on the front.

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    Quote Originally Posted by localzuk View Post
    Personally, I wouldn't buy interface cards. I'd instead buy a gateway device such as this - Vegastream Vega 50 Europa Gateway 8 x FXO.
    I've only just got my quad-BRI Vega 50 working 'properly' for Lync... frikkin nightmare!

    Lync is another option depending upon how you license your Microsoft software. If you have Enterprise CALs it's pennies more and a comparable price to Asterisk.

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    Wow great comments here, just one basic question I wonder if there is an agreed answer:

    What steps should I take before arriving at a decision to install a VOiP system?

    Thanks again!

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    Quote Originally Posted by matthogan View Post
    Wow great comments here, just one basic question I wonder if there is an agreed answer:

    What steps should I take before arriving at a decision to install a VOiP system?

    Thanks again!
    The most important aspect to consider when thinking about this is infrastructure. Can you guarantee that your switches will be able to provide the level of service that a phone system demands? If your switches are congested, you'll need to look at upgrading them before your phone system is even considered.

    What about backup plans? If your network goes down, what do you plan to do instead? Will you need UPS's on all switches or just on those areas which are vital?

    Can your switches provide PoE to your phones? If not, how will you power them? Individual plugs (what if the power goes off?)? New switches? PoE midspan devices?

    What capabilities do you need from your system? Do you have *nix knowledge to use an asterisk system yourself, or would you want to get a commercial voip system in?

    I'm sure there's more. I'll post again if I think of it.

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    Great considerations

    Quote Originally Posted by localzuk View Post
    The most important aspect to consider when thinking about this is infrastructure. Can you guarantee that your switches will be able to provide the level of service that a phone system demands? If your switches are congested, you'll need to look at upgrading them before your phone system is even considered.

    What about backup plans? If your network goes down, what do you plan to do instead? Will you need UPS's on all switches or just on those areas which are vital?

    Can your switches provide PoE to your phones? If not, how will you power them? Individual plugs (what if the power goes off?)? New switches? PoE midspan devices?

    What capabilities do you need from your system? Do you have *nix knowledge to use an asterisk system yourself, or would you want to get a commercial voip system in?

    I'm sure there's more. I'll post again if I think of it.
    Great just want I want any more considerations I need to make will help?

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    Quote Originally Posted by pcstru View Post
    Even a G.711 64kbs uncompressed codec wouldn't stress a 100Mbs connection. But where you have multiple lines going through the switches, then being able to prioritise VOIP traffic through the switch is essential. You won't run out of bandwidth but if latency rises, the call quality will tank. For the original poster, this is one area you MUST deal with before arriving at a decision.
    QoS is only needed if you have congestion on the network. If your devices forward at wirespeed (which is most things these days) and you're not hitting any interface limits then the frames aren't getting queued anyway so there's nothing to prioritise. If you do have congestion then yes look at QoS or even better increase your connectivity.

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    Quote Originally Posted by funkymunky View Post
    QoS is only needed if you have congestion on the network. If your devices forward at wirespeed (which is most things these days) and you're not hitting any interface limits then the frames aren't getting queued anyway so there's nothing to prioritise. If you do have congestion then yes look at QoS or even better increase your connectivity.
    True as stated, but without QOS you would need to guarantee that you will never hit those limits. All it takes is a number of people transferring largeish files over those switches at the right time and the quality of someone's call is likely to tank. Without QOS you can't guarantee the quality of calls. Unless you are massively over-specifying your network, you are putting yourself in a position where you are waiting for a problem to happen before you fix it. And if you are massively over-specifying your network then you are effectively wasting money.

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    Quote Originally Posted by dhicks View Post
    What happens if there's a power outage - do we need to have phones or PoE switches attached to UPSes capable of running the handsets for a given amount of time?
    Does anyone use a UPS with a PoE capable switch or midspan? Is it even a practical idea?

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    Quote Originally Posted by dhicks View Post
    Does anyone use a UPS with a PoE capable switch or midspan? Is it even a practical idea?
    We have a UPS on our admin office PoE switch, and another on the central core switch. Works fine, and keeps the phone system running for a good hour during power outages.

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