Intelligent Solutions

Network changes

Simon Woodhead

Simon Woodhead

24th August 2018

We invested hugely in our network in 2017, or more accurately, continued the program we’d started in 2016. That hasn’t really stopped, with the addition of DDoS mitigation capabilities and substantial increases in our transit edge capacity through 2018.

We don’t actually use much in the way of transit as 90% of traffic enters or leaves the network over public peering (LINX etc), or more-so over bilateral private peering (direct fibre between us and other networks). However, it is essential we have that transit capability to ensure availability of multiple sites in a number of different failure and attack scenarios. We’ve added over 60Gb/s of new edge transit capability, much more than that in private peering, and have 1Tb/s+ of DDoS scrubbing on standby in addition to that, should it be needed.

We’ve also been growing our optical capabilities, replacing what was layer2 ‘ethernet’ connectivity between sites supplied from third parties, with our own or mutually leased dark-fibre, or optical waves wherever possible. Either way, where we’re lighting the fibre, we’re in control and issues don’t get obscured lower down in the stack. We don’t use much in the way of our inter-site capacity for voice either, as we tend to service voice customers from the PoP they land on, but it is essential for the survivability of the network and customer services, e.g. a transit customer in Slough reaching a directly connected peer in London.

All of this flows through our highly available multi-Terabit Arista core, which at the time represented a new (and conventionally ‘barmy’) way of doing things – using ultra-low-latency switches as routers in order to improve port-density. We’ve talked about this lots over the last 2 or 3 years and are reassured that others are now moving this way. It has certainly paid off for us.

Our transit, optical connectivity and ethernet are all available to customers – get in touch if you have a requirement! Similarly, if you are not already directly connected, please speak to us.

There’s one notable exception to all of this progress however, and that is Manchester. We’ve long had a dark fibre ring there but the presence in 3 data centres wasn’t a choice, it was a necessity brought about through market consolidation. Manchester has missed out on many other upgrades and continues to do so. Quite frankly, there has never been the business case to justify the investment. So whilst it runs newer equipment than many networks, it isn’t current Simwood generation like the rest of the network. We only have a handful of directly connected customers there and it carries a very small proportion of our voice traffic – less than 1%. Considering, Slough and London carry 79% of traffic between them, and even our new US PoPs carry 21% (yes, we’re flying over there!), this is insignificant enough to be lost in rounding and certainly doesn’t justify presence in 3 data-centres.

Manchester historically provided a strategic location in that it had the only transit out of the UK that didn’t depend on London; this isn’t the case any more. It also completed the triangle of our three Availability Zones by providing a backup path between London and Slough. This role, and indeed the role of being somewhere for DR customer equipment is now fulfilled by our Bristol office, which is fully on-net at high speed. Bristol also houses our secure lab and is used for staging / testing production customer installations before deployment to a full data centre. This is tremendously useful as we’re physically on-hand there and have a great working environment which customers are welcome to make use of.

If you haven’t already guessed, the upshot of this is that we will be retiring Manchester at least as far as customer facing equipment is concerned. We have SS7 interconnects there so we won’t be leaving completely, but it’ll essentially drop off our IP network map. The logical time for this is February 2019 given contracts on the buy and sell side, but we will be winding it down between now and then. We’ll be in touch with affected customers with more specifics.

This is not a cost-cutting exercise, lest the usual suspects try and misrepresent it that way! The saving is substantial but that will be committed to other PoPs. In fact, we’ve already begun committing the savings that won’t come until next year to ensure the network remains quite simply the best in the world for voice business. By consequence, it’ll also remain amazing for cat pictures and porn!!

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