Quite possibly the Achilles’ heel of ADSL, is the fact that its coverage is entirely dependant on two variables:
1. Local exchange being ADSL-enabled
2. Distance from the exchange
3. Line quality
Providing the local exchange is ADSL-enabled, you cannot be any further than 5.5 kilometres from the exchange. Providing that the local exchange is enabled, and you live within the 5.5 kilometres, there is a third hurdle to jump over – the quality of the line, between exchange and building, must be of a high enough quality to successfully carry the data signal. For the many colleges and projects either on the fringes/in the suburbs of a town or city, this is easier said than done, and many rural areas will be left out in the cold, until either BT or someone else find a way of bringing them into the system, possibly via wireless and/or Government-funded projects.
Secondly, BT Ignite has only recently begun to give service-level agreements (SLA’s) to ISPs, on their commercial ADSL packages [7]. Naturally, an ISP would be taking a large risk in producing an SLA off its own back, and subsequently the end-user wouldn’t usually receive one. This is dynamite: with no SLA, nothing is guaranteed, from speeds, to even uptime. The link being down for a few hours on an afternoon would be catastrophic to a college that has grown reliant on its presence, never mind a couple of day’s downtime. This is perhaps why many organisations are using ADSL as their main link connection, but a number of ADSL routers are equipped to use ISDN as a backup link; should the main ADSL link fail, the router automatically connects to the ISP via ISDN, providing a redundant, if not limited link, ideally suited to restore only primary systems, such as very basic web browsing for an academic network, or email. At this current time, no SLA’s exist for users of “residential” packages, which could cause large problems if online systems are implemented at educational establishments, for the deployment, development, and submission of tasks and assignments online.
Finally, from a security perspective, ADSL does offer a larger risk from intruders, compared to traditional Internet links.
Commonly with modem and ADSL links, the system disconnects periodically, and you are allocated a new IP address (dynamic) every connection.
Providing that a hacker/cracker (or whatever your terminology suggests) was making headway in breaching a college network, then this would be lost upon reconnecting, and the potential intruder would generally have a very hard time finding you again – if they ever came online again before their patience wore thin, of course.
Considering the large databases an academic institution, such as student records as well as a large number of personnel files which are increasingly being held electronically across the organisation’s local area network (LAN), this is a very real and important danger, which requires significant attention, effort, and possibly money in order to ensure security systems are in place, as well as effective contingency planning should the worst occur.
ADSL Problems
