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Confusion reigns part 2: EFM and other TLAs


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In part one of my blog, I looked at how the consumer internet service industry has caused a lot of confusion about what you actually receive from your broadband service. Having cleared up some confusion and explained the terminology, I wanted to take the opportunity to look at some services that may actually deliver what they say on the tin – specifically, EFM.

EFM stands for Ethernet First Mile. In other words, if you are within one mile of the exchange you may be able to get good Ethernet performance to deliver your internet service. It bundles the same copper pairs of cables in the first mile of the internet circuit (typically where the bottlenecks occur) and this helps to increase speed and resilience. It is uncontended so that means if you’re paying for 20Mbps upload and download speeds then that’s what you’ll get.

Typically, some providers offer what’s known as ‘bonded’ ADSL. This is where you bundle together three or four of those contended lines we talked about in the first blog. So now you’re able to receive about 8Mbps in the same scenario (10:1 contented lines), but you are paying four times the amount and any one of those connections could experience delays. This is when EFM becomes a more reliable option for a similar price.

EFM is a great idea, however, like everything in life, the free lunch does come at a price. Don’t be fooled though, it isn’t directly comparable to Ethernet on Fibre – if it was it wouldn’t be so much cheaper. Since it is based on metallic cables running across the analogue circuits from BT Openreach, the electrical signal is susceptible to things like twists and crushed points, cracked or broken insulation and this will affect performance. Fibre doesn’t suffer in the same way.

However, EFM is a cost-effective alternative to ADSL and the ideal solution for using as a backup for Ethernet Leased Lines or where there is no Ethernet coverage. When compared to ADSL and SDSL lines EFM may have an increased delivery time and be slightly more expensive when it comes to rental costs but these are offset by the increased capacity and performance, improved SLAs and agreed bandwidth levels available.

As with all services, pay attention to the small print. Some suppliers don’t even offer EFM within their solutions because their networks are simply too old in design to support it, or they’re unwilling to ‘break-out’ from the core BT network. Others offer only limited QoS (quality of service) and may even charge for a guarantee. Some suppliers start with a very low EFM speed option. Of course it is priced less than standard EFM but in this case you most certainly get what you pay for.

My last piece of advice is that if you’re really unsure what your needs are consider the four wire service. Yes it costs a bit more but you cannot upgrade a two wire EFM to a four wire EFM service, it is a new provision completely. What you can do in an MPLS and internet provision environment is to install a second two pair and run the connection as an active/active (where both lines are working to provide double the bandwidth)!

I hope that you’ve found these two blog post useful and that they’ve helped to provide some clarity.



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