by Rich Adam. 10-01-13. It seems to be a tradition here at Virtual1 that most blogs start with a very tenuous analogy to introduce the subject, a tradition I suspect perpetuated by our erstwhile CTO.
Well, all I can promise is that I’ll do my very best not to break the unwritten rules of tradition and to that end I’m going to wheel out the Olympics in the form of these two chaps.
What you can see here is that there is simply too much athlete to fit through the available doorway.
Happily this puts me in mind of Quality of Service (or QOS for short) and I think keeps me well within the bounds of tradition.
QOS is something that we engineers spend a lot of time contemplating and building on our core and customer networks. It’s designed to prioritise one type of traffic over another and the most common use is to ensure applications like voice and video take priority over emails and web browsing. Why? Because voice and video are very latency and loss-sensitive: all packets must arrive in a timely fashion, in the right order and without any delay or loss, or the communication will breakdown.
If it takes too long for packets to get from one phone to the other then conversations can fall apart and before you know it everyone has to suffix each sentence with “over”, over.
If some of the packets get lost or arrive out of order then our voice breaks up or starts sounding like a voice synthesiser as the phone desperately tries to work out what the packet should have looked like and come up with its own. Bzzzzzz.
So how does QOS help? QOS is – in its most basic form – a series of queues that are applied to both ends of the circuits which look at the traffic flowing through the pipe. In periods of congestion, it will queue up less important or latency tolerant traffic while allowing the higher priority or sensitive traffic first. This means that it may take a few more milliseconds for your webpage to load or your e-mail to arrive but you won’t notice because you’re currently on the phone to Bob from order admin about that massive deal you’ve just won.
Setting up QOS is often considered a bit of a dark art and to some extent it is, I’m afraid I cannot debunk a rumour that is largely true. There are a variety of “auto QOS” offerings out there and they do a reasonable job but they kind of miss the point, or the real benefit of QOS, which is that you can choose which programmes have priority over each other, in order to give priority to the applications which are the most important to your/your customers’ business. So to make QOS really work for you and keep your customers happy, you need to work with both the end customer to understand their requirements and the provider to ensure they tailor their QOS offering to the customer’s traffic profile.
Over and out.