For connectivity there are 4 key metrics that need to be consistently met. If the performance of the connection drops even slightly for any of these metrics at any point sensitive applications like VoIP will suffer. Significant or longer issues will have a notable impact on every aspect of your business.

• Bandwidth – how much data your connection can pass in a given time
• Latency – how quickly your data gets from your office to the service provider network
• Packet Loss – how much data reaches the destination
• Jitter – the variation in latency

To ensure business grade call quality for VoIP the following should be consistently achieved when measured from mouth to ear:

Latency <150ms

Packet Loss <1%

Jitter <45m

SLAs are based on a calculation that uses network monitoring statistics to determine performance. A Calculation then compares these statistics to your SLA thresholds to determine if there is a fault. How the SLA is calculated and over what time frame are therefore important details. For example;

A circuit with a 99.9% uptime SLA measured annually could be down for a whole working day yet be within SLA

The same SLA measured monthly gives a maximum outage of only 44 minutes before breaching SLA.

Which of these SLAs better suits your business?

What does a guarantee actually offer? A good SLA will tell you what happens if the SLA isn’t met. This may for example be service credits until the issue is resolved which is a huge incentive to the supplier to keeping pushing for a resolution.

However look out for “guarantees” that don’t solve your problem. A provider who offers a discount on your rental if your bandwidth drops hasn’t resolved your issue – the service may be useless, you’ve just reduced your bill slightly.

What use is a guarantee that reduces your service fee but doesn’t rectify the shortcoming?

There’s a good reason performance SLAs are offered on some circuits – because these circuits are designed for consistently high performance. The type of performance that ensures demanding applications like Voice over IP work consistently.

SLAs are a clear differentiator that allow you to make an informed choice. If there is no SLA available chances are that the technology either cannot support a consistent guaranteed level of performance or the service provider has designed the service to reduce cost.

All connections should be offered with a support SLA so make sure you understand which service level you sign up to.

Different circuit types are capable of supporting different performance SLAs. For example a Broadband circuit such as FTTC broadband by design has many variables that make it difficult for a service provider to offer any useful level of performance SLA. You may get a minimum target bandwidth or prioritised traffic but even these are rarely underpinned by any contractual obligation. Conversely ethernet circuits are designed to optimise network performance and remove the unpredictability caused by network congestion. Performance SLAs do still however vary. It is not uncommon for a performance SLA to only be offered on a proportion of the allocated bandwidth. This may well suit your needs but requires careful router configuration to ensure the mechanisms in place are correctly utilised.