Getting the most from your broadband connection


With remote access to College suddenly being thrust to the fore during the current Covid-19 pandemic and now becoming an essential service rather than a 'nice to have' option, here are some tips on troubleshooting common problems and getting the most from your connection.

Broadband providers

Generally, all of the well-known internet server providers (ISP's) provide a service usable with Imperial College online services but there are significant differences in cost, reliability and in the consistency of upload/download speeds.

For heavy usage or extensive remote working you might want to consider a business broadband connection. These don't cost much more than a domestic residential connection but do have some advantages that may be important to you; line faults and roadside cabinet faults get fixed on the same day they are reported or by the next business day, there is much less network bandwidth contention with other users, one or more static IP addresses are available and nearly all TCP ports are open and usable (port 139 used by Windows for SMB network discovery is almost always blocked on business connections to protect customers from themselves!). With most ports open you can run mailservers, webservers and all sorts of things which are always blocked or prohibited on residential connections.

Here are some sample screenshots of broadband speed test results; these were all taken within a few seconds of each other on a PC that could be switched quickly between connections to both TalkTalk and Zen Internet FTTC (Fibre To The Cabinet, also known as VDSL, fibre or SuperFast) services and VirginMedia's Voom 500 cable broadband service.

TalkTalk:

TalkTalk DSL broadband

As you can see, TalkTalk is not providing the connectivity speeds you'd expect from a VDSL/FFTC connection (~76 Mbit/s download, ~18 Mbit/s upload) at this time although this connection has reached these figures at other times.

Zen Internet:

Zen Internet DSL broadband

On the other hand, the Zen Internet connection consistently meets the stated download/upload speeds at all times together with high reliability. All Zen Internet connections give you a static IP address which is useful if you want to connect to devices within your home from outside such as security cameras or if you are running gaming and webservers at home.

Virgin Media cable:

Virgin Media cable broadband

If you live in an area served by Virgin Media cable, very fast download speeds of around 550 Mbit/s (just over half of what you would expect from a standard college Ethernet gigabit network connection) are possible on a business broadband connection with up to 300 Mbit/s available on residential services although long-term reliability of the connection is not quite as good as BT or Zen Internet.

For all three of the above connections the ISP's supplied routers were not used (in the case of the Virgin Media connection, the supplied Hitron cable modem/router was retained but switched to modem-only mode feeding into a separate router) and DrayTek 2860 series routers were used instead which does make a big difference to performance and reliability. Despite their quaint retro 1980's look and beige casings, they offer a vast range of features (the English language version user manual alone runs to almost 1000 pages) with a high network throughput - highly recommended if you are a network geek!



Andy Thomas

Research Computing Manager,
Department of Mathematics

last updated: 8.5.2020