To answer that question, one may need to ask another. What is the goal of the 3gb cap?
Just to put the cap in perspective :
It is not a technical means of limiting bandwidth utilisation. It does not throttle your bandwidth utilisation at any point in time, until you hit the cap at which point you will be technically throttled ( and mentally as well [

]).
I quote from a Telkom letter.
'The 3 GByte cap protects users from a small minority of people who abuse the service and use it for purposes it was not intended for.'
<i>Maybe we should start a thread to get people's views of what they think the ADSL service is intended for, as clearly, according to Telkom, there is a minority out there who doesn't [

] I include myself in that minority of course</i>
How does a 3gb cap protect the users. In my opinion, it is a cheap way of trying to manage bandwidth consumption. It is a very negative approach because if this limit is exceeded, the client is <b>punished</b> by degrading his service to such an extent that it almost becomes unusable.
There is also a lot of uncertainty as to how this cap is calculated. Again I quote from the same letter.
'The 3 GByte is measured on total usage, both local and international, volumes up- and downloaded.'
That's maybe what Telkom would like people to believe, but i know for a fact that this is not the case. Or at least it was not the case a few months ago. Maybe Telkom decided to change their minds as they often do without due consultation.
When i first encountered this cap in February/March, I approached one of the senior officials in Telkom and challenged him on the fairness of the capping system. Telkom expects it's clients to adhere to this volume cap or else they are penalised. How does a client monitor his own utilisation? If I cannot measure my utilisation, how the hell am i supposed to know when i've exceeded my cap? Well in the good old days, you just woke up one morning and found yourself capped. It was so bad that I logged a fault the first time it happened only to be told that i've been capped.
As a result of this discussion, or it may have been discussed already, Telkom decided to introdue this usage page where you can now see how much you are using.
Be it as it may, it still does not answer the question of what the goal is. In my humble opinion, Telkom expects people to consider their overall utilisation and as a result would force people to slow down their downloads and spread it over the month. This is a very crude and maybe effective way of managing volumes. Does it happen? Clearly not, as we still sitting with a very crappy service. I think you made a comment in one of your other posts as to how people can circumvent the 3gb cap. Get a second account. What if we all do it? Now we are slamming the network with 6gb each per month.
<b>Does it work? NO! </b>
This is clearly proven by the fact that Telkom was forced to implement yet another crude solution in the form of network shaping. This does limit utilisation in a big way, but I believe that they have now succesfully destroyed the ADSL service by doing it. Again it was a decision Telkom made without due consultation.
<b>Is it a good thing? NO!</b>
There are other ways of managing a network by using more sophisticated technology where people can be given a choice as to how much they want to download and what type of access they require. It can be used to provide a tiered service where people pay a premium for more volume and could also cater for a more sophisticated bandwidth allocation based on the client's specific requirements. What this premium should be may be yet another topic of discussion.
Obviously Telkom does not see the need to spend the extra cash to ensure a good service to their clients. What's new[

!]