^ White, C.M.; Teague, K.A.; Daniel, E.J. (November 7–10, 2004). Browse Conference Publications > Signals, Systems and Computer ... Help Working with Abstracts Packet loss concealment in a secure voice over IP environment (PDF). Signals, Systems and Computers, 2004. Conference Record of the Thirty-Eighth Asilomar Conference on. 1. pp. 415–419. CiteSeerX doi:10.1109/ACSSC.2004.1399165. ISBN 978-0-7803-8622-8.

Choose the service that is appropriate for your calling needs. Residential VoIP plans are cheaper than business VoIP plans because: (1) they have fewer features and (2) residential phones are used less frequently than business phones. Don’t use a residential VoIP service for a home-based business unless you’re willing to pay overage fees or to have your VoIP service canceled. VoIP providers are serious about enforcing their Fair Use guidelines.
As a consultancy marketing business for small-business owners, part of our business is to help small-business owners set up their VoIP and local phone numbers. We used to have RingCentral, and we advised our clients to use it. RingCentral gives you a local phone number regardless of whether you are in the building or not—or even in the city. You will always have a local phone number that you can redirect to any cell phone, depending on who’s working in the company. RingCentral offers good customer service and has great flexibility, but it’s a bit expensive.
If you want to compare pricing for multiple residential service providers you can use our Home Phone Rates Tool. Please note that the pricing does not include additional fees like sales tax, regulatory fees and any other taxes/fees that may be relevant to your location. These tend to be the same for each provider as it is based on location, however, some providers may include additional "recovery" fees for the overhead involved in state and regulatory compliance (e.g. FCC reporting compliance).
BYOD stands for bring your own device. This term refers to employees conducting company business on personal laptops, tablets, and phones instead of on company-owned gear. Most VoIP companies offer BYOD features and solutions within their plans, either included or at additional cost. However, extra IT security layers and company guidelines for BYOD are on you.
Businesses working remotely should keep in mind, though, that Ooma doesn’t offer any videoconferencing tools. Instead, you get a conference line that lets at-home employees collaborate over the phone. That puts Ooma a pace behind some of the other providers on our list, but with providers like Nextiva currently offering their video collaboration tool to businesses for free, it shouldn’t be a major issue.
Network routers on high volume traffic links may introduce latency that exceeds permissible thresholds for VoIP. Excessive load on a link can cause congestion and associated queueing delays and packet loss. This signals a transport protocol like TCP to reduce its transmission rate to alleviate the congestion. But VoIP usually uses UDP not TCP because recovering from congestion through retransmission usually entails too much latency.[16] So QoS mechanisms can avoid the undesirable loss of VoIP packets by immediately transmitting them ahead of any queued bulk traffic on the same link, even when the link is congested by bulk traffic.
SIP is built to work on a peer-to-peer (meaning endpoint to endpoint) basis. Those two points are called the "user-agent client" and the "user-agent server." Remember that those points can be swapped, so that in SIP, the endpoint making the call is the user-agent client initiating the traffic and endpoint receiving the call is the user-agent server receiving the call.
If that all is starting to sound more complex than it's worth, remember that turning your PBX into a software solution means significant opportunity for flexibility and integration that you simply can't get any other way. After all, programmers can now treat your phone like an app. Where that's taken us is to the fast-changing UCaaS paradigm (more on that below). Here, traditional VoIP providers, like the ones we review as part of this review roundup, provide additional software capabilities that are all implemented and managed from a single, unified console.
A critical part of the discussion with your IT staff will be whether your existing data network can handle the extra load that will be placed on it by the new phone system. You'll need a network that can handle more advanced network management capabilities, including tools to fight jitter and latency as well as to provide Quality of Service (QoS) and different kinds of network segmentation, especially virtual LANs (VLANs). Only tools like these can help free up your network from too much congestion, which can cause your call quality to decrease or even crash the VoIP system entirely.  
It is much cheaper than a regular landline - most providers offer unlimited calling plans (including long distance) in the USA and Canada for under $10 per month. There are also some great promotional deals available such as 2 year specials that cost around $6 per month (includes all your calling). Comparing this to a regular PSTN (landline) phone service that can cost in the region of $60 per month can result in savings of over $500 per year for many home phone users. If you also regularly call International numbers you can save even more, with rates typically starting from around 1 to 2 cents per minute to many countries.