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View Full Version : 3GB Cap vs Port Cap



Merlin2003
02-08-2003, 02:13 PM
I see these two cappings as two different issues, each having it's own consequences. I would appreciate some feedback from the more knowledgable members.

My Version:

The 3GB cap is essentially a measurement on data up or downloaded and occurs over a period of time. There are many issues pertaining to this cap and i will limit it to 2 issues:

1) Is the measurement based on the uploaded OR downloaded traffic or both? (M-Web seems to think it's up OR down and they have an agreement with Telkom to that effect)
2) Is the measurement based on all traffic or just the international traffic? I understood this to be applicable only to international traffic, following discussions with one of the executives about 4 months ago. That is why Telkom was forced to provide the usage tracking page because the international traffic can only be measured in one place, SAIX. If it was a simple case of the measurement of all traffic, we could have done this on our PC's. This has been one of my arguments with ICASA against Telkom, which i believe led to the implementation of the Usage Tracking Page.

The port capping issue is by far the most destructive of the two capping mechanisms and has never been mentioned in any communication by Telkom as being a feature of ADSL. Yet, they have done this. It has only been in existence since about February, following the big disaster that Telkom had during that month where the ADSL service took a massive dip. This port capping feature effectively destroys any traffic that is not HTTP, PoP and FTP.

I am not realy bothered about the 3GB cap because i don't use ADSL for massive downloads, however, I do not agree with it as a matter of principle. I am very much against the port capping mechanism, as I believe this has the greatest impact.

My understanding of the effect of these two capping mechanisms:

3GB Cap

No real impact (theoretically speaking) in terms of data troughput and everyone should still be able to download at theoretical speed of 64KBytes/second. If you do hit the cap, then you, and only you, will be moved to a slower international link. This will greatly affect your data throughput, international only, and according to M-Web, will be a bit slower than 64Kbits/second or a theoretical download speed of about 8KBytes/second.

So, if i understand this correctly, then we should all be happy until we hit the cap. This is not the case as we are all experiencing much less than the theoretical.

PORT Capping

I personally believe this has the biggest impact on our data throughput, especially if you are using ports other than HTTP, Pop and FTP. This imposes a permanent cap on ADSL and any trafic not destined to the above mentioned ports, will be de-prioritised (delayed) and will result in much slower data throughput. So whether you have hit your 3GB cap or not, you will still experience the port capping pain.

We cannot just blame all our problems on these two aspects because there are other factors that influence the data throughput, one being Network Congestion.

Now this is a natural phenomena on all networks and the impact it has depends on how good the network management is. This is a direct result of total bandwidth divided by the number of subscribers. I know there are other salient factors that contribute to congestion, but let's leave it simple.

Now, to put all this into context of Telkom:

Before they launched ADSL they should have considered the following:

Cost of ADSL infrastructure initial setup and projected growth. Now most commercial companies know they have to make an initial capital investment which has to be depreciated over a period. There are many factors that drives this calculation. To keep it simple, they must have had a ADSL subscriber growth projection as part of their Marketing plan. This growth projection will determine at which point ADSL will start making a profit. Obviously, the growth projection will also provide details of the cost growth, as each subscriber will need a modem, DSLAM port, BRAS capacity and bandwidth capacity. The Bandwidth requirements, both local and international, should be based on the number of expected subscribers projected along the timeline.

Typically, this timeline is not shorter than 5 years.

I believe Telkom has done this, but have not fully understood the impact or consequences of ADSL. To justify my comment I have to mention my own understanding of the events since January 2003.

1) The 3GB cap was not enforced initially. It was only brought into play, in my experience, in about February 2003.
2) ADSL initally shared the same ATM network as dial-up. This was changed after they found out that ADSL was affecting the dial-up community by taking all their bandwidth. This was changed quite early by putting ADSL on it's own ATM and were allocated it's own international bandwidth. This was limited to 10mb initially and if i have to believe Telkom, it has been upgraded since to about 14mb.
3) Port capping was never mentioned but is now a feature of ADSL.


So, my humble opinion of ADSL is that it started OK, until Telkom had to face up to the demand that suddenly appeared. I believe they have underestimated the takeon of ADSL and have not made provision for this growth in their initial plan. There are other more politically sensitive issues such as the ISDN or dedicated line population migration to ADSL. I believe Telkom has factored this into their plans, but again, I don't think they realised just how quickly this would happen and the volumes.

As a consequence, Telkom is forced to bring in all forms of capping to stabilise the ADSL network.

If Telkom was a commercial company, they would have failed in their objective to deliver a product. They would have failed to deliver on their initial Marketing Plan.

They would have been bankrupt! Like those many telco's in the world who have failed to make ADSL work. Only the best Telcos managed to do this and do it sucessfully.

So from my point of view, Telkom just demonstrated to me just how pathetic an organisation they are and I cannot believe that they are rated amongst the top 30 in the world!

But allas, they are a monopoly. And as such they feel no need to be open and transparent to their clients and believe they can get away with it. They probably will.

ItalicBold
02-08-2003, 04:38 PM
AFAIK The cap is on total BW (Combined DL + UL of both Int and Loc BW).

DigitalSoldier
02-08-2003, 11:26 PM
nice post merlin i just wish telkom would'nt have capped the ports thats just bs they should have mentioned that in there ads aswell

plug
03-08-2003, 01:32 AM
I seem to have mistakenly believed that the cap has been only for international sites. I downloaded the Redhat distributions from ftp.saix.net somwhere in May/Apr and after I have been capped I phoned the support people explaining the situation. The reply I got was that the bandwidth usage tracked is local and international.

Maybe they recently changed it? Really hoping so.

rpm
03-08-2003, 01:39 AM
Hi Merlin

Thanks a bunch for the excellent posting. It gives all the members a good idea what our problem is all about.

I think most senior people involved in this project would just like it to go away. Helpdesk has informed me that they may not give the contact details of any senior personnel involved, and I think helpdesk is simply there for the sake of blowing off steam. Unfortunately we are reminded about the problems every time we use the net, and I for one will continue to pursue this matter.

The sad truth is that they are continuing to sign on new members without solving any problems. The service is deteriorating as we speak. I just had a ping time of over 100 000 ms on a game site at 01:00 on Sunday morning. My friends with ISDN are finding this rather amusing. I must say that my view is slightly less comical. One thing I will push for is that, if they realize that they cannot provide us with the promised service, that they refund us and give us ISDN at no cost. This will cost Telkom millions, and I think they might just opt for letting the service deteriorate to such an extent that it becomes nearly unusable. We will have to migrate back to ISDN at our own cost. I think it will all hinge on ICASA at the end.

Thanks again for the great posting. I hope there will be many more.

Regards,

RPM


RPM
rpm@myadsl.co.za

DarkHelmet
03-08-2003, 03:18 AM
I don't think it is a port cap, probably more a priority thing to HTTP/FTP/POP3. You can see it as a cap. It is the one thing about the ADSL link the peeves me the most. I connect to a VPN and just use the 256MB outgoing to get my traffic out. The VPN is on a local server...

So why prioritise? Simple, I dunno the stats, but think about it. Most people just browse the web and download mail, they see a significant improvement in their "web" experience. Us powergamers and other powerusers bear the grunt.

We are the minority. Telkom scores, they get a fixed income from surfers who were promised faster speeds. Us few that used to pay R5000 per month for ISDN get corked. They get more money by signing low key users up to ADSL than us few early adopters that want the speed.

The more "average" users they sign up the better, us few that sit online and want bandwith - well we are in the minority

Merlin2003
03-08-2003, 08:18 AM
You are right about it not being a port cap, Dark, but i'm running into sematic and jargon problems here. Some people see it as port capping whilst others see it as traffic deprioritisation.

It is a very crude way of network management, the same applies to the 3GB cap. Both of these mechanisms do not care about Client Satisfaction.

I think you are correct in your assumptions that Telkom wants ADSL to be used by the average user and not by the power users. That is why they are continuing to 'break' the service to get rid of people like us. We cost too much! We are not part of their target market.

The questions on my mind are:

How much in the minority are we? Hopefully this Forum will give us some answers.
How many people can afford ADSL for average usage? This will be answered by the first question.
Is Telkom's target market sufficient to sustain the cost/profit ratio of their model? Let's all cancel and see.

Where do we, the supposedly power users, go to for our requirements?

ISDN? Did you know that network shaping is also applied to ISDN?
Get a dedicated line? Not on my budget.

<b>Conclusion :

We are up the creek without a paddle or between a rock and a hard place! </b>

<b>The hard part about this is that Telkom knows it.</b>

rpm
03-08-2003, 01:04 PM
Hi Merlin

It is unacceptable that Telkom makes decisions, and implement them, without even informing their clients. Port prioritization is similar to limiting phone calls to any 0800 or non-local number in order to limit traffic. There will be a tremendous uproar if they even try to implement phone call limitations, but it seems like many people simply accept this scenario when it comes to data services. Maybe a lack of knowledge plays a big part.

The part that gets my back up is that Telkom ignores us. They are not even willing to tell us what we are paying for! I informed them in my letters that I can guarantee them that we will not lose steam, and that the longer they procrastinate, the bigger the problem for them will become. I will do my best to ensure that it gets tough for them, and hope I will have some support.

Regards,

RPM


RPM
rpm@myadsl.co.za