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erol · 18-04-2004, 22:47

Just some general info on BT based DSL products. This may not be the right / best place for this info so mods please move it if you think appropriate.

BT based ADSL services fall into the following categories depending on the BT wholesale product used by the ISP in question.

BT IP Stream based services
BT Data Stream based services
LLU based services

BT IP Stream.

This wholesale product essentially moves data all the way from an end users house to a central POP for the ISP concerned (typically it moves it to telehouse but not always). The connection from the end users house to the local exchange is uncontended. From the local exchange to the ISP's POP it is contended. BT offer two _maximum_ contention ratios for this section fo the connection (though in reality the actual contention is much lower) and they offer two speeds. So you end up with four options

512/256 @ 20:1
1024/256 @ 20:1
512/256 @ 50:1
1024/256 @ 50:1

The majority of ADSL ISP's use the IP Stream product. The wholesale price for these products id 'flat rate' (that is there is no usage charge element for the ISP)

BT Data Stream

This wholesale product essentialy moves data from the end users house to the local exchange. The ISP then has to pay BT or a third party supplier to move the data from the local exchange to their POP. The ISP is free to contend this section of the journey to any level they see fit. This product is also the same price for the ISP regarldess of what speed service they actualy supply to the customer. That is the datastream cost to the ISP is the same for a 512 user as for a 1meg user. The datastream product still uses BT's DSLAM* in the local exchange, but then allows for the data to be moved onto a competitors network from there. As such the products that can be offered via this system are limited by the capabilites of BT's DSLAMs

LLU

Local Loop Unbundling was a regulator (EU) mandated product that BT was required to offer. With this system the ISP put's their own DSLAM into a local exchange. They pay BT for 'space' in the exchange and they also pay BT a fixed fee for each phone line attached to thier DSLAM. They also have to pay someone (BT or 3rd party) to move the data from local exchange to thier POP. As the ISP owns and specifies their own DSLAM they can offer services that are not available using BT's DSLAMs (like SDLS and others). There are basically only two companies using LLU for commercial/retail services atm. Easynet (aimed at business users) and Bulldog (aimed at reidential and business). These 'extended' services can only be offerd on those exchanges where the ISP has put a DSLAM in. In areas where they have not put in their own DSLAM they use datastream.

So basically with IPStream the ISP is dependnet on BT as to what services they can offer and the contention ratios of these services. With IP Stream the ISP get a bit more flexibility but is still limited to what the BT DSLAMs can support. With LLU based systems the ISP has ultimate flexibility in the serivces they can offer. This is why Bulldog's products (where they have put a DSLAM in the local exchange) are so different from all the other ISP's offering (excpet for easynet which also use LLU).

18-04-2004, 22:47	#437
erol Inactive Join Date: Oct 2003 Location: cyprus Posts: 510	Re: [merged] Price increase Just some general info on BT based DSL products. This may not be the right / best place for this info so mods please move it if you think appropriate. BT based ADSL services fall into the following categories depending on the BT wholesale product used by the ISP in question. BT IP Stream based services BT Data Stream based services LLU based services BT IP Stream. This wholesale product essentially moves data all the way from an end users house to a central POP for the ISP concerned (typically it moves it to telehouse but not always). The connection from the end users house to the local exchange is uncontended. From the local exchange to the ISP's POP it is contended. BT offer two _maximum_ contention ratios for this section fo the connection (though in reality the actual contention is much lower) and they offer two speeds. So you end up with four options 512/256 @ 20:1 1024/256 @ 20:1 512/256 @ 50:1 1024/256 @ 50:1 The majority of ADSL ISP's use the IP Stream product. The wholesale price for these products id 'flat rate' (that is there is no usage charge element for the ISP) BT Data Stream This wholesale product essentialy moves data from the end users house to the local exchange. The ISP then has to pay BT or a third party supplier to move the data from the local exchange to their POP. The ISP is free to contend this section of the journey to any level they see fit. This product is also the same price for the ISP regarldess of what speed service they actualy supply to the customer. That is the datastream cost to the ISP is the same for a 512 user as for a 1meg user. The datastream product still uses BT's DSLAM* in the local exchange, but then allows for the data to be moved onto a competitors network from there. As such the products that can be offered via this system are limited by the capabilites of BT's DSLAMs LLU Local Loop Unbundling was a regulator (EU) mandated product that BT was required to offer. With this system the ISP put's their own DSLAM into a local exchange. They pay BT for 'space' in the exchange and they also pay BT a fixed fee for each phone line attached to thier DSLAM. They also have to pay someone (BT or 3rd party) to move the data from local exchange to thier POP. As the ISP owns and specifies their own DSLAM they can offer services that are not available using BT's DSLAMs (like SDLS and others). There are basically only two companies using LLU for commercial/retail services atm. Easynet (aimed at business users) and Bulldog (aimed at reidential and business). These 'extended' services can only be offerd on those exchanges where the ISP has put a DSLAM in. In areas where they have not put in their own DSLAM they use datastream. So basically with IPStream the ISP is dependnet on BT as to what services they can offer and the contention ratios of these services. With IP Stream the ISP get a bit more flexibility but is still limited to what the BT DSLAMs can support. With LLU based systems the ISP has ultimate flexibility in the serivces they can offer. This is why Bulldog's products (where they have put a DSLAM in the local exchange) are so different from all the other ISP's offering (excpet for easynet which also use LLU).