Reliability in the Local Loop

If you have a call center of any size, with voice and data needs and don’t already have a redundant route into your facility, then this story is for you.   Digital facilities that connect to your premise from a long distance company are called local loops, and they traverse what is sometimes referred to as the ‘Last Mile’.    To make those facilities truly redundant you need to do more than simply order and install more than one circuit.  You need to ensure that those redundant facilities are designed in a fashion that they are likely to survive most of the common events that cause local loop outages.  

Let’s say you order two T1’s from two different long distance providers.  While it is true that those two facilities may traverse the country on two different networks, chances are they are coming in to your building on the same copper or fiber optic cables from your local phone company.  So if a backhoe down the street drops its’ shovel through that cable, you and all your phone services are going to be down despite having 2, 3 or any other number of long distance providers.   If High Availability is important to you then you need to make sure your local loop is ‘Highly Available’ as well.  Different Local Phone companies may have different names for the product, but most of them should have a family of services known as Self Healing Network Services (Qwest calls their service SHNS).  The idea is to install two sets of cable (usually fiber optic) to your building, where each cable takes a path or route that ensures that the cables are separated by enough distance that something such as a backhoe cannot cut through both cables at the same time.  They will usually even try to enter the building at different points.    Both of these cables will be connected on each end to electronic systems that are able to detect the loss of any one of the cables, and quickly switch traffic to the other cable without disruption of service.  If you are serious about redundancy and service protection, you should talk to your local phone company about their self healing network services.  It is not cheap, and it will probably require a multi-year contract but it is essential if you want to try to ensure reliable services in to your facility. 

So you installed a self healing network in to your building, you’re safe right?  Not necessarily.  In 1988, there was a fire in the Hinsdale central office near Chicago that caused severe outages over huge sections of the country, not just the immediate area around the central office.  Central office fires do not happen often but when they do, it is usually disastrous.   If the central office servicing your network catches fire,  you are probably toast unless you went the extra mile and had the services installed using two central offices with your carrier facilities strategically installed in to each of the two CO’s that service your building.   Going to lengths such as this are usually only cost justifiable when you have very large telecommunication needs, but it is an option.

So, when ordering Intelligent T1s or even your own local dial tone services, consider your uptime requirements, the number of calls or the amount of data you handle and if you need the extra protection for your services, consider looking in to a self healing network solution.