May 18 2018

3 Tips for Switching to Cloud for VoIP

A second internet circuit and firewall can help you on your way to lower costs and higher-quality calls.

School districts moving their phone systems from old-style analog or digital private branch exchange to cloud-based Voice over IP expect to benefit from lower overall costs, higher quality and modern features. But it’s important to lay the foundation in order to reap the rewards. Making the switch means revisiting security mandates and ensuring the network is sound and prepared for VoIP. Here are three tips for making the switch:

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1. Get Started with the Right Bandwidth

Cloud-based VoIP doesn’t take a lot of bandwidth, but it’s not tolerant of poor-quality bandwidth either. Therefore, don’t share your normal internet circuit with VoIP traffic. Take advantage of low internet service prices and add a second internet circuit dedicated to your cloud-based VoIP. The cost should easily be covered by the money you don’t spend on analog or digital services from the phone company. Plus, a second circuit comes with a nice bonus: You can fail over from one to the other for improved reliability.

Of course, there’s a catch: Internet traffic is asymmetric — much more download than upload. VoIP traffic is the exception to that, very symmetric, with equal volumes of inbound and outbound traffic. This means that your standard low-cost asymmetric DSL circuit won’t do; you’ll need fairly hefty upstream bandwidth for cloud-based VoIP. It doesn’t have to be symmetric, but for a typical VoIP codec, you’ll need at least 50 kilobits per second per expected simultaneous call; 100Kbps is even better. If you’re using a 64Kbps codec, bump that to 100 to 180Kbps — and for voice and video at the same time, multiply those numbers by 10.

2. Don’t Let Your Firewall Slow You Down

Most unified threat management firewalls — the most popular for schools — will cause brief slowdowns as they scan for viruses or perform other threat mitigation. UTM slowdowns are imperceptible to web browsers but conspicuous with VoIP traffic. So while you’re installing a second circuit, consider getting a second firewall at the same time.

The good news is that you don’t need to pay for a UTM subscription. Dedicating a second firewall to a single application — cloud-based VoIP — means that you can use a simpler configuration and don’t need to apply all of the subscription-based UTM features, such as URL filtering, anti-malware and intrusion prevention. You’ll need to choose a firewall that has a good VoIP application layer gateway and customer support, but that’s about it. As always: Test before you commit. Not every firewall is compatible with every phone system.

3. Don’t Worry About LAN Segmentation

In large VoIP networks, people often go to great lengths to segment their LAN data and VoIP traffic with special VLANs, 802.1p quality of service and other complicated features. That’s fine — it won’t hurt anything. But a typical school’s gigabit LAN with 100 or 200 stations per subnet is not going to have a problem mixing VoIP and other data traffic.

Of course, every network is different, and if you do have very high loads (for example, if you’re running disk-to-disk backups over the same LAN), segmentation might help.

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