VoIPowering Your Office: Reduce Hair Loss with VoIP Gateways

By cutting the local telco in on the action (leasing a gateway), you can both improve and simplify your VoIP service.

 By Carla Schroder
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The VoIP world has something for everyone, from hardcore do-it-yourselfers to folks who would rather hire everything done. There are also a lot of in-between options, so today we're going to look at one that applies to a wide range of circumstances and offers what I think is a lot of bang for the buck: using a VoIP gateway.

Comtrend has released a new small business and enterprise VoIP gateway, the CT-814M, which takes a different approach from the usual VoIP gateway device. Andrew Morton, the Vice President and General Manager of Comtrend's North American division, was kind enough to give me some background on the CT-814M and where it fits into your network architecture.

Smart networks, smart endpoints
In the beginning, the telephone network was smart, and the telephones were dumb. They only did one thing: initiate and receive phone calls. All the heavy lifting went on behind the scenes. Then came the VoIP revolution, and the humans were left behind. Well not really, but using IP networks for telephony has finally made advanced services like videophones, conferencing, multiple devices per user, and private VoIP WANS manageable realities. It's also made protection from eavesdropping possible by using ordinary IP network tools such as VPNs and public-key infrastructures, though these are limited in scope, and there still isn't a universal, lightweight, transparent encryption protocol.

Splitting the workload
VoIP gateways are not new; there is a large number of brands and models to choose from. Typically you can choose from features such as FXS/FXO interfaces, Ethernet, T.38 support for faxing, 911 support, PSTN fallback, T1/E1 interfaces, multiple codec support, jitter buffer and echo cancellation, QoS and packet filtering, conferencing, and so forth. They are good, cost-effective devices that solve a number of problems, with SIP NAT traversal and QoS at the top of the list.

Using a standalone VoIP gateway removes a significant processing burden from your iPBX server. Asterisk was invented back when x86 PC hardware was considerably less expensive than telephony gear, so it was cost-effective to use an Asterisk box as a PSTN gateway via Digium's own FXS/FXO interfaces, or those of competitors such as Sangoma and Rhino. But that cost advantage has disappeared, so your iPBX box can be just an iPBX, and not do double-duty as your PSTN interface.

Ideally you will have a dedicated Internet line for your VoIP. Putting a VoIP gateway between your VoIP server and the Internet, on its own dedicated Internet connection, makes it a lot easier to administer and secure, and you'll get better call quality. You'll also avoid conflicts with DHCP and DNS—VoIP servers that support auto-provisioning phones include their own DHCP/DNS servers, so trying to manage these in harmony with your existing nameservers gets complex. It's easier to dodge the problem entirely by putting your IP phones and servers on a separate network.

Many hats
Anyone who wants to manage their own iPBX and network needs a broad skillset: system administration, telephony knowledge, and network administration. Thanks to Asterisk and the VoIP revolution, VoIP do-it-yourselfers have been given unprecedented control and flexibility over their telephony. But it doesn't hurt to look at what tasks you can delegate, and this is where the CT-814M fills a useful niche.

First some specs: The CT-814M is a four-port PSTN gateway that supports four analog phone lines; it includes four Ethernet LAN ports, an Ethernet WAN port, a stateful packet inspection firewall, content filtering, echo cancellation, jitter buffer, 802.1P and Q QoS, and a batch of calling features such as call waiting, call blocking, fax/modem passthrough, click-to-dial, and various other goodies.

Rolling fewer trucks
Moreover, it comes with complete remote administration capabilities, including remote firmware upgrades. While anyone can buy one, the CT-814M is targeted more at ILECs (Incumbent Local Exchange Carriers) and CLECs (Competitive Local Exchange Carriers)—from the customer's perspective, the local telco. The idea is to offer the customer more bundled services with full remote management capabilities. It's similar to ordering a T1 line, and haivng your telco bundle a router into your package. They it install it on your premises, and configure and manage it for you. The only time the telco needs to get a truck to your location is to install the device; after that it's managed remotely.

There are several advantages to this approach: You can probably negotiate a good deal with your telco, and you have technicians from the mother ship taking care of the gnarly bits. Then all you have to do is manage your VoIP server, and this can be any server you care to run—Asterisk, Trixbox, SipX, PBX in a Flash, or any of the many others that we have to choose from.

An even bigger advantage is call quality. By dealing directly with your telco, you can be protected by an SLA (Service Level Agreeement), because the telcos have complete control of their wires. Resellers like Vonage and Skype do not, so you are at the mercy of random events on the Internet. The telco benefits as well, by offering more services and controlling the device remotely, which saves a ton of money and time.

VoIP is growing up
If your business depends on reliable phone service, don't bet the farm yet on VoIP—you still need the PSTN both for reliability and call quality. I've had way too many conversations over bad VoIP and cell connections, and I don't care how cheap it is when most of the conversation is "What? Are you there? Hello?" It's not like the telcos are going to disappear anyway—who do you think maintains the wires the Internet travels on? And no matter how much we tuff old do-it-yourselfers resist, I think the future of VoIP is hosted services. Just like today's telephone services, only far more advanced and cheaper.

This article was originally published on Mar 3, 2008
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