We're looking at moving our office shortly and we'll need to get our own internet connection (we currently have a 7Mbps LAN connection in our current building).

We're based in the UK (centre of London) and we'll need at least a 5Mbps connection. We currently have 10 in office people with 2 VPN users: however, we'll be looking at expanding (within 2 months: hence the need for the new office) to at least 18 people in the office and 6 VPN users. We would also like to use the internet connection for Voice calls using VoIP. 4 people tend to use it for basic email/basecamp work (around 5-10Mb files), others a graphic designers (50Mb files), a couple watch streaming video from time to time (mainly the big boss), there is some online game play (not MMOs though: more flash games) for research and then 3 developers working with around a 100Mb code base.

Given the choice between a leased line, ISDN lines, Bonded ADSL or just a bunch of ADSL lines: which would you recommend and why? Any you would particularly avoid and why?

I know my choice/recommendation, but I'm asking here as somebody else here has a widely differing opinion and I'll like to check with true techs!

  • In any case, we will be having an additional ADSL line for emergency failover/backup (but obviously we won't be able to run fully on it for any length), but would still require a high QoS on the main system.
    – Richy B.
    Aug 4 '09 at 11:53
  • For the record, we've settled on a 10Mbps leased line from Enta.net .
    – Richy B.
    Aug 13 '09 at 9:52

Avoid ISDN like the plague. I'm honestly shocked that telcos are still offering it in London; it's seriously old-hat tech, won't give you adequate bandwidth, and will cost you a small fortune (actually come to think of it I'm not surprised telcos are offering it...)

My own feeling is that cost is only one factor to consider here. You're going to be in a position where reliability of the connection and the ability to guarantee a certain level of performance (which will have to be at least comparable to your old 7 meg circuit) will be crucial.

Bearing that in mind, I would lean towards keeping things as simple as possible - the less there is that can go wrong, the less there is that will go wrong - and running with a leased line. I don't know what costs in the UK are like, but you might find that if you run a procurement/tendering exercise you can get substantially lower prices than if you just go direct to BT or whoever.


You can bond 4 ADSL Max Premium lines together easily so that you can get around 2.4mb usable bandwidth upstream. It's theoretically possible to bond more than that, but at that point it's worth looking at the management of your bandwidth more carefully rather than letting everything have a free for all.

It is also possible to bond SDSL and ADSL Max together.

So with that you get big upload of the SDSL and the big download of the ADSL Max together, with all the failover and resilience of having it bonded.

VoIP can be prioritised too, depending on how many concurrent calls you use - you might want to dedicate a line to VoIP, while maintaining failover to other lines in the bonded connection if it goes down.

Check out www.evolving-networks.co.uk and they'll show you reference customers with all of those set ups.

  • Many thanks - what advantageous/disadvantageous would you say Bonded ADSL has over a Leased line? (which is more what I was after)
    – Richy B.
    Aug 4 '09 at 12:51
  • Advantages - certainly cost is the biggest factor. Mixing SDSL and ADSL Max is great for not relying on one particular technology at the exchange - faults can develop that affect either/or, so if the SDSLs go down, you still have the Max lines and you only notice the speed decrease. Disadvantages - Most people point to the SLA for a leased line, but if you read the small print, the SLAs are very similar these days, and you aren't likely to get much money back if the connection goes down, even going direct to BT for a leased line.
    – Nic
    Aug 4 '09 at 12:59
  • You can still have a static public IP range as well with a bonded broadband connection, and it's not tied to any single line. So you can lose for example, all but 1 line (any line) and still maintain a fully routed connection.
    – Nic
    Aug 4 '09 at 13:00
  • DSL needs BT at some stage, even if you go for LLU, BT still maintain that last mile, so there is always that to consider. But most bonded providers will manage that relationship anyway, so its their hassle not yours!
    – Nic
    Aug 4 '09 at 13:02

I am not an expert in this field but I would like to add that a leased line is also not limited to lower speeds like some of the other technologies are, there is nothing to stop you (with the exception of cost!) upgrading the leased line to higher speeds in the future should your business require it.

For example, whilst 5Mbps might be OK now, you may find you wish to upgrade to 10/20/50 Mbps in the future.

Hope this helps,


  • +1 for upgrade potential, very important point. Aug 4 '09 at 15:30
  • Yep, we've just got to make sure if we go down the leased line route we have the appropriate bearer installed. A 10Mbps copper or fibre bearer means we can't upgrade over that much, but a 100Mbps fibre bearer whilst giving us more expandability will cost more for the install (and per month for some reason according to some quotes).
    – Richy B.
    Aug 4 '09 at 16:17

A lease line will be expensive. ISDN will not give you anywhere near the bandwidth you require. A bunch of ADSL lines will be a complicated setup.

I'd recommend Bonded ADSL.

  • But would Bonded ADSL provide the upstream bandwidth we require without additional complexity (I've only come across 2 UK bonded ADSL provides: and they only seem to support a couple of ADSL lines bonded). We'll be using it for VPN and VoIP along with normal internet access.
    – Richy B.
    Aug 4 '09 at 11:56

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