At the heart of an excellent VoIP service is an excellent connection to the Internet. But what does a good internet connection look like? Is it a download speed? An upload speed? A connection ratio at the DSLAM?
In saying “connection to the Internet,” we aren’t just referring to your internal network, router and switches etc., but also the folk who route your calls globally, the Tier One Telephone providers. Most of which will be using VoIP service themselves. So where to start?
Well it’s simple, it all comes down to stability
While there are many factors to a good internet connection, at the core is stability. A lot of internet traffic uses the TCP/IP Protocol – a tactic that has been used since the 1970s. In those days, internet speeds were a fraction of what they are today and relatively unreliable. One handy feature of this protocol was if a packet (a piece of data) happened to get lost, the software would be aware and request it to be resent.
While this works for video and music streaming (through buffering), it’s useless for voice. Shouting HELLO over and over again doesn’t quite work. Voice demands a more stable connection than any other application.
At byphone, we use a measure called Jitter to assess the stability of a connection. We access the variability over time of packet latency (delay) in a network with no latency generating a score of zero. A high-quality network will have a score of under 4ms. If the Jitter score is high (above 10ms), then it’s likely that voice data will arrive after it’s useful. The moment will have passed, and it will get dropped from the call.
A quick measure of Jitter will tell you whether an internet connection has the potential to carry voice. However, stability implies time. Jitter tests should be therefore be conducted over some time, to build a more accurate picture of the overall connection stability.
So, what are the factors that affect your networks Stability?
1. How efficient is your standard broadband for voice?
Many people will tell you that their internet connection will get download speeds of 10mbps and up, (theoretically enough to carry 50 voice calls), so it should be fine. Well, several factors can affect this.
ADSL (the standard in broadband) works using electrical signalling. Electricity can be unstable and can vary with power surges or contact with substances like metal, magnets etc. The longer the connection has to run to an exchange point, the higher the potential for interference. Proximity to your connection is critical when using this type of broadband, as a connection a mile away from an exchange (electrical signal) will be more stable than one that is 5 miles away.
2. Is Fibre better?
The simple answer is, yes. As this technology uses optical light pulses, there is no degradation in signal when connecting to the local exchange. Your connection will be as secure at five miles away as it is as at one mile away.
3. Bonded Pair – are we stronger together?
Ethernet-based multi-pair bonding technology is connections made for businesses and carries performance assurances that can provide stability. However, they are expensive and have limited capacity. It can be hard to justify the additional expense given the more restricted the capacity. These types of connections are best when using a leased line or when a fibre line is not available.
4. Leased Lines, is it worth the price tag?
These lines are a business-grade product that guarantees enhanced performance and provides the most stable connection. This improved performance is a little more costly, but the expense can be shared with data connection and used to improve your overall stability.
If you choose this route, it’s essential to partition part of the line specifically for voice to protect against data swamping (more on that later). The line needs to be partitioned at installation, to avoid being hit with substantial additional costs when routers are then required to partition the line.
5. Is Contention an issue?
This only affects those connections with limited capacity. Mainly, if the local exchange is busy, then the connection will get shared with all the other users and can have a noticeable effect on stability when the connection is weak already.
6. Data swamping – Does capacity improve stability?
Internet protocols try to download files as quickly as the connection or equipment will allow. So if you are file-sharing or streaming from YouTube, the connection may become saturated or fully utilised. Sometimes the Internet providers will throttle the connection a little, particularly during video sharing where they may limit the speeds to a 1 Mbps set by the local exchange.
Take Fibre, for instance – with a shared Fibre connection (data & voice) the aim is that the capacity or throughput of the connection doesn’t fill up. However, we are relying on the ISP to throttle the download speeds and quality of service (QOS) settings on the router to throttle the upload speeds.
Even with this, voice can get swamped by data on the network itself. As the protocol instructs packets to fill all available bandwidth, the swamping can occur at switch or router levels before the data can be managed.
So technically, a shared high-speed data connection with reasonable quality routers should be enough to avoid data swamping. However, this isn’t always the case. Sometimes the call quality suffers – it’s recommended to keep the voice and data separate on the network and divide connections to the internet.
Using separate connections, therefore, makes it impossible for data to swamp the voice as they use different networks and connections to the Internet.
7. Is your internal equipment up to the job?
Switches need to have enough processing power to handle the voice traffic promptly. Older switches combined with high traffic can lead to stability issues.
Routers depend on the speed of their processors. To handle large amounts of data, they need modern processors and can also manage outbound traffic with quality of service (QOS) settings. This prioritises the outbound voice traffic going through that router.
Cabling that is older than ten years may have degraded to the point that it affects stability. In some cases, our engineers have seen cabling secured by metal stables which impairs the stability of the electrical signals.
What’s the best course of action?
A good connection needs stability, with the capacity to serve as a buffer for other variables that can affect performance.
A strong recommendation is to separate the voice and data networks with separate connections to the internet. By combining the connection, you are relying on a much more comprehensive management system and hoping that the ISP throttles some inbound services.
That’s why at byphone, we developed the Voxbox series of tests, to assess the suitability of a network and a connection for voice connections.
