Help me understand ADSL & ISP's

Grant

Grant

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So, Telkom provides us with an ADSL line for internet access.
Then, we need an ISP.

Just what is it that an ISP is adding into the line Telkom gives me, that is not already there ?

Am I right in assuming an undersea cable links cape town / south africa with the rest of the world.
That cable lands at / connects to who, SAIX ?
Then others (telkom, mweb, afrihost etc) are connected, or join us to SAIX (again, not sure if SAIX is correct).

Exactly what function does an ISP serve, or as questioned earlier, what is it they add that is not already there ?

I feel really dumb - but hey !
 
Telkom only provides the physical layer from your door to the breakout point wherever that is.

Your ISP does the "management" of the data usage of that line together with the billing and cost of bandwidth etc.

Your ISP runs an authentication server that you connect to which also does accounting of your usage and then bills you accordingly.

The only reason it gets complicated is because Telkom is also an ISP.
 
grantza said:
right, this is where my confusion comes in.

where do they get that "data" from ?
is it not from that same undersea cable
Click to expand...

Yes, but Telkom only has one of those cables (or is it two now) while there are a few others by other companies.

Your ISP pulls those all together and brings you multiple options.


Also the cables operators (of which Telkom is one yes) aren't interested in dealing with the dramas of 50 million users across the country, they only want to deal with a handful of partners and have them deal with the 50 million users.


So they sell in "bulk" and their resellers (the ISP's) do the legwork.


Put it this way if you had to deal with Telkom directly....you would need to be a Cisco engineer to have any understanding of what was going on.
 
SauRoNZA said:
Also the cables operators (of which Telkom is one yes) aren't interested in dealing with the dramas of 50 million users across the country, they only want to deal with a handful of partners and have them deal with the 50 million users.


So they sell in "bulk" and their resellers (the ISP's) do the legwork.


Put it this way if you had to deal with Telkom directly....you would need to be a Cisco engineer to have any understanding of what was going on.
Click to expand...

But Telkom is already an ISP, that people deal with on a daily basis
 
grantza said:
But Telkom is already an ISP, that people deal with on a daily basis
Click to expand...

You have just discovered a very important fact: If Telkom ISP was any good there is no business case to be made for the other ISP's....
 
chrismine said:
You have just discovered a very important fact: If Telkom ISP was any good there is no business case to be made for the other ISP's....
Click to expand...

Why? There are many reasons to have active competition than a monopoly.

Then there is the whole LLU debacle…
 
Okay let me see if I can give an explanation that works:
An ISP is simply any entity (company or individual) which provides Internet services. In general a company presents itself as an ISP if its primary line of business is providing internet connectivity to customers or to "lower tier" ISPs - contrary to their claims MWEB and Telkom are NOT Tier 1 ISPs. Internet connectivity entails the ability to transmit (send/receive) IP packets to (every - at least theoretically) other connected node on the Internet but this is not accomplished by having connections to every node but rather having autonomous networks interconnect (forming an internet or global area network)

So at Internet Exchanges autonomous networks exchange packets and the consequence is that as soon as you can get a presence at an INX where you can share traffic with other autonomous networks. In theory you should have a situation where the owners of networks simply share traffic on the basis of recouping costs from members of their network but the reality is that one network (the smaller one) usually pays the other a transit fee on the basis of the amount of traffic.


Now the South African ADSL setup is broadly speaking as follows:
There is a copper line between your house and an exchange (telephone not Internet) this line is leased by the customer from Telkom at a subsidized rate (the analogue line rental).
There is a DSLAM or MSAN or whatnot which the line is plugged into and which connects to and is aggregated at an ESR and put onto Telkom's backhaul network. This is handled by Telkom and either the customer pays Telkom or purchases the product on a wholesale basis through their ISP (the ADSL rental).
The traffic is taken off the Telkom national backhaul network and put onto an ISPs network and this is done at an ESR and the ISP pays Telkom for IPConnect on a capacity basis. It is important to note that Telkom Internet is an ISP that purchases IPC on the same terms and conditions (and pricing) as other ISPs and at this point the ISP has control of the traffic. Because the traffic has to follow through on Telkom's last mile (and actually hundreds of miles) ISPs have little ability to enforce quality control but ultimately the determining factors of the sort of internet connectivity depend on the ISP (which if you are using Telkom is Telkom).
Traffic which is destined for the ISPs own network continues on that ISPs network whereas traffic destined for another network is handed over where convenient and appropriate. Now most SA ISPs peer with each on a free peering basis and so at the INXes - JINX and CINX for example traffic is handed over to the destination ISP as part of peering, also a lot of content is hosted on different ISPs networks locally. BUT transit is not intended so traffic that has an international node to which it needs to connect to then the packets will have to be carried to an international INX where peering or connecting to a transit network is possible. To accomplish this South African ISPs lease capacity on the undersea cables who in turn connect to other networks and INXes. One of the reasons our Internet costs will be higher than other countries if because we have to pay to get our traffic to them whereas they are simply there waiting for people to peer in their home turf (the Netherlands and the UK for example).
Finally it should be remembered that most brand ISPs don't have their own massive network but rather assemble up using another backhaul network - so Afrihost uses MTN and other guys use IS. What the ISP that you pay a bill for really does is pay a whole lot of other bills to other wholesale ISPs (and in the case of Telkom pay over to another part of the company) and they try to get as much value in a very competitive market with different vendors.
 
My next question - line speed & their respective costs.

How is this determined ?
Let me try articulate a little better:
We can opt for different line speeds at different costs, why the availability of the various speeds at their respective prices, slower than the maximum available speed in the country. Why is everyone not connected at the maximum speed that is available ?
 
grantza said:
My next question - line speed & their respective costs.

How is this determined ?
Let me try articulate a little better:
We can opt for different line speeds at different costs, why the availability of the various speeds at their respective prices, slower than the maximum available speed in the country. Why is everyone not connected at the maximum speed that is available ?
Click to expand...

Because we don't have unlimited backhaul bandwidth. If you use more, you pay more. The more people that make use of a faster speed at a dslam, means Telkom needs to lay more fibre which costs more.
 
grantza said:
But Telkom is already an ISP, that people deal with on a daily basis
Click to expand...
There's a difference between Telkom Wholesale, and Telkom Internet. The one is the operator, the other is the ISP. 2 different entities.
 
grantza said:
But Telkom is already an ISP, that people deal with on a daily basis
Click to expand...

The ISP is run as a separate business all together.

When you call Telkom about a line issue I don't even think you can ask them to put you through to the ISP section, it's a whole different company.
 
Is there possibly anything one can do to get there sync speed up? Caused by distance from the exchange.
 
James1996 said:
Is there possibly anything one can do to get there sync speed up? Caused by distance from the exchange.
Click to expand...

If your problem is caused by distance from the exchange then well sadly your only solution would be to move closer to the exchange. Unless you have other line issues? Give this and this a read.
 
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