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We are moving into a new space and moving to a full VOIP environment. Up until now we have used standard land lines and used consumer routers (like the LinkSYS RV042).

In our new space we are getting faster Internet (100mbit) and going to 14 VOIP phones.

New space details:

  • 14 people
  • 14 LinkSYS SPA-942 VOIP phones
  • 100 mbit Internet connection
  • 18 mixed Windows, Mac and Linux desktops
  • Several internal servers (not public facing)

I'm wondering:

  1. Do you recommend the VOIP phones go into the same router as the rest of the network or two routers (1 for VOIP, 1 for all else)?
  2. What kind of router or routers do you recommend to handle all this traffic?
  3. With 14 VOIP phones do we need to do anything to prioritize traffic for the phones on the router, or is not not necessary with a small deployment?

Thanks!

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Very interested in this. One of our remote office is using consumer routers and was working fine until the numbers increase. Then suddenly seemed like the NAT tables couldn't cope and all the VOIP phones started failing randomly during the day. Powering off some laptops or phones fixes the problem. –  Ryaner Dec 23 '09 at 21:20
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4 Answers

up vote 3 down vote accepted

There are two schools of thought as far as the network for the phones goes --

  1. Keep voice and data separated so that a failure of the primary network doesn't affect the phones. The phones gotta work, man, so they should have their own switches and have the voice network terminate in PBX that has it's own connection to the firewall.
  2. Make the whole network as reliable as possible. Why should the voice part of it be the only thing that's reliable? All ports should be able to provide POE and dial-tone VOIP QOS. End of story.

I firmly believe that with modern equipment it is pretty easy to create a unified network that provides high levels of reliability for VOIP and standard data applications.

For instance, with something like the Enterasys C3 switches you can create policies that give one class of device (based on 802.1x or MAC) super high QOS but only at most 300kbps of bandwidth. Everything else gets a lower QOS but is allowed as much bandwidth as needed. They do lots of other cool policy based stuff as well as the standard POE / L3 routing (static routes, ospf and rip).

Just be sure you've got big UPSs on all equipment that's needed to support 911 / emergency calls.

If you're going to go with unmanaged switches or switches that can't protect your network from things like broadcast storms or other DOS type things, you will want to chop your network into voice / data, but I believe doing so makes the network unnecessarily complex.

Oh, and as far as your border goes, use a router such as a netscreen 5gt that can make sure that you have bandwidth and memory and ephemeral ports set aside for the VOIP traffic, if you're using a sip trunk service such as callcentric.

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I presume that you are connecting the phones to a VoIP phone system elsewhere, rather than to a local VoIP phone switch. If that is true, the phone provider will likely have an opinion. Be aware that their opinion serves their needs (reducing support calls), not necessarily your needs (ease and cost effectiveness).

Do you recommend the VOIP phones go into the same router as the rest of the network or two routers (1 for VOIP, 1 for all else)?

I recommend a single network. Set the phones at the desk, connect them to the main switch, and plug the PCs into the phones. A single 24 port switch will suffice, provided it has PoE. Confirm that the switch can provide maximum load to all of the ports at the same time! I have had good luck with HP ProCurve. Get redundant power supplies on the switch, and a good UPS with battery backup. Do the math to make sure you have several hours of battery life.

Plug the internet router and the servers into the same switch. You will end up with a clean, easy to manage network that will perform well.

Setting up two networks sounds cleaner, but it isn't. You end up with twice the hardware, which means twice the expense and triple the management hassle. You may need to setup VLANs and put the phones on a separate VLAN, but I doubt it will be necessary with 14 phones. You should be able to configure DHCP to allocate the phones and PCs to different pools if you are so inclined.

What kind of router or routers do you recommend to handle all this traffic?

I defer to others on this question, as I have only done local VoIP. That said, I don't think it will be that much bandwidth ( < 800 Kbps max). You do need to make sure that the router supports QoS, and ideally that you can get QoS all the way to the phone provider.

With 14 VOIP phones do we need to do anything to prioritize traffic for the phones on the router, or is not not necessary with a small deployment?

With 100Mbps to the internet and local Gigabit, you should be fine as long as you get sufficient bandwidth (~ 800Kbps) to the phone provider. Check with the phone provider to see if they require anything. They likely recommend Quality of Service (QoS), and may require it.

If you start getting bandwidth-related problems, setup QoS. The telltale sign of bandwidth issues is the calls getting tinny. You setup the phones, the switch, and the internet router, and have the internet provider configure it.

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"Set the phones at the desk, connect them to the main switch, and plug the PCs into the phones." If you are setting up a new office and have enough cables & wall outlets, I would not use the phones' switches, but connect the PC's directly to the main switch. Just seems cleaner to me. –  Marie Fischer Dec 28 '09 at 16:45
    
Then you need twice as many switch ports. For managed PoE switches, these are more expensive than the phones! –  tomjedrz Dec 29 '09 at 6:45
    
Yes, but adding an abstraction layer between my PC and the Intertubes just slows it down, ever so slightly. –  Justin Dec 31 '09 at 16:08
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  • What do you mean by router ?
  • What kind of switches do you use ?
  • Do you have a voip provider ?
  • How the voip phones are set up ?
  • Do you have budget to do it right or it has to be cheap ?
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- A router is a device that lets you create a network. See: en.wikipedia.org/wiki/Router - We have an un-managed Dell swich ATM, but we can buy new ones. - RingCentral - "How the voip phones are set up ?" Please explain this - "Do you have budget to do it right or it has to be cheap ?" Bit of a dubious question. We have the budget to build an efficient, secure and reliable network, yes. –  Justin Dec 24 '09 at 14:48
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It'd almost certainly go for a Cisco Catalyst 3750V2-48PS. The reason is that it's a very capable L2/L3 switch with 'Power-over-Ethernet' that I know for a fact works great with that specific phone and plenty of people have the same combo. It's not the cheapest L3 switch out there but it's pretty damn powerful, small, takes a redundant power-supply if required and is reliable as you get for this kind of work. You may also wish to consider the upgraded, 1Gbps-capable, version the Cisco Catalyst 3750G-48PS, more expensive obviously but will deal with your PCs and servers far better than the 100Mb-only option.

Feel free to come back to me with any follow-up questions ok.

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I have had good luck with the HP ProCurve line. It is cheaper and has lifetime warranty. –  tomjedrz Dec 24 '09 at 9:23
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