BT sure has initiative.........
High speed networks: what comes after ADSL?
Broadband access has spread across Britain in the past couple of years at a staggering rate. But what comes next?
It has been said that ISDN failed to reach its potentially massive market to the sluggishness in promoting and rolling out the technology.
ADSL roll out, on the other hand, has been very slick. But it doesn't stop here - the next big thing is the so-called 21st Century Network (21CN), a converged broadband, Ethernet and voice infrastructure.
This is all part of a general trend among operators to change to Internet Protocol (IP)-based networks. Unfortunately, there are still several questions that remain unanswered.
What version of IP?
Under normal circumstances, the obvious choice for an upgrade would be IPv6, the successor to IPv4. However, the feeling among some industry watchers is that the amount of IPv4 equipment installed means that it will be some time before there is a general move to version six, if ever.
"There is a legacy of how everything has been built up," said Richard Proctor from Waveney Consulting. "There is too much equipment that won't work with version six. The main telecoms networks will be some hybrid of version four."
He said he could only see version six being used in closed environments, such as within a private network. For the main network he said version four would be improved and expanded.
"Version six will disappear into the distant future," he said. "There is no evolutionary route to version six."
IP over what?
As for what the IP will be running on, today ATM is the obvious choice but this will be migrating to MPLS in the near future to achieve the necessary quality of service. MPLS stands for multi protocol label switching and can bring ATM-like quality of service and traffic management features to IP networks.
A lot of existing equipment that was not designed to work with MPLS has been tweaked to do so. However, much of this is not capable of providing full traffic management capabilities, which means that a move to MPLS will involve a lot more equipment being installed. In the short term, though, MPLS is not a complete standard and many companies have their own proprietary versions. A potential standards nightmare could take a few years to sort out.
"When MPLS is fully implemented, it will be good," said Proctor. "But MPLS is not a finished job yet. In three to five years, MPLS will be able to do what it is supposed to."
BT is also looking at Ethernet as an alternative to ATM to provide scaling and flexibility. A key factor is to offer controllability to other service providers who will use the network.
"My system architect colleagues are looking at where to put the control, whether in the MPLS layer or the Ethernet layer," said Angus Flett, director of product management at BT Wholesale. "The great thing with MPLS is that it allows you to set up virtual channels and guarantee parcel performance.
But at the end of the day, it is still just a best-endeavour network."
What about optical fibre?
On broadband in general, the speed at which developers are pushing the limits of copper with ever-faster flavours of DSL has slowed down the roll out of optical fibre. The predicted dates at which there would be fibre to the home or at least fibre to the kerb have been and gone many times, and these days even the best pundits wave their hands and shrug their shoulders to avoid naming the day.
"Fibre to the kerb in this country will probably never happen because the cost would be astronomical," said Proctor. "We will see fibre to the green box on the street and then DSL from there. This will involve updating junction boxes but not digging up the streets. Fibre to boxes is starting to happen and will be widely available in five to ten years."
Even BT is only rolling out fibre on a customer-by-customer basis as economics dictate. And Flett acknowledged that, with the progress on copper, it was unlikely that fibre would be economically viable in a big way for some time.
"The ability of the guys at Martlesham (a BT research laboratory) to get copper networks at higher speeds is incredible," said Flett. "I am not sure it is a big issue now on whether we will replace copper with fibre everywhere until we have exhausted the technical capability of copper."
Likelihood of all-digital?
And so to 21CN, BT's big plan to create an all-digital network based on IP and offering various options for its customers.
The company is taking the work seriously and has earmarked £10bn of investment over the next ten years starting with a pilot programme in Cardiff. During the second half of 2006, existing voice, broadband and Ethernet services in the area will be migrated to the new network.
"A fair proportion of the £10bn will be spent on moving from a historic architecture to a more integrated platform," said Flett. "We want a network with greater economy and efficiency."
About 350,000 customers will be involved in the pilot including many served by other telephone operators, internet service providers and mobile phone companies.
"It is a move away from the existing telephone exchanges," said Proctor.
"Everything will be digital. It is a big leap, but it was going to come sooner or later. It will be everything over IP at the core even if the end user doesn't realise it."
Flett agreed. He said: "We want to move legacy voice onto an IP environment.
The users shouldn't notice the difference."
Part of this will be moving the architecture to being soft-switch based.
This will allow the development of new services and capabilities that would be too expensive on existing networks because it would involve changes to every switch throughout the network.
Proctor said he hadn't seen any sign of other operators in the UK following a similar route and said the only likely one would be NTL. NTL was asked about its plans but said no spokesperson was available.
Flett, though, said that the other operators would benefit from 21CN because they were also customers of BT and used its infrastructure.
"From a wholesale perspective, our customers are also probably our competitors," said Flett. "That is a very positive thing. The likes of NTL, Cable & Wireless, Energis and so on are all our customers. We want them to be able to integrate their applications seamlessly into ours. That is part of being a good wholesaler."
Possibility of 100% coverage?
Meanwhile, BT still has the difficult issue of getting broadband to that final 15% of users who live too far away from their local exchanges to make ADSL workable. Part of that problem is being solved with repeaters that can extend the reach of ADSL, which should take coverage to 95%.
"The final 5% will be really difficult," said Proctor. "This is where users are really remote or on really poor quality cabling."
One answer would be to use wireless broadband technology. This would let the network expand without putting in an expensive infrastructure.
Wireless also is likely to spread into other areas as a way that rival operators can come in and compete with BT without using its wired access.
But Flett said: "We are looking at wireless broadband in the way we are looking at all technologies, but there are no immediate plans to deploy it right now on a large scale."
High speed networks: what comes after ADSL?
Broadband access has spread across Britain in the past couple of years at a staggering rate. But what comes next?
It has been said that ISDN failed to reach its potentially massive market to the sluggishness in promoting and rolling out the technology.
ADSL roll out, on the other hand, has been very slick. But it doesn't stop here - the next big thing is the so-called 21st Century Network (21CN), a converged broadband, Ethernet and voice infrastructure.
This is all part of a general trend among operators to change to Internet Protocol (IP)-based networks. Unfortunately, there are still several questions that remain unanswered.
What version of IP?
Under normal circumstances, the obvious choice for an upgrade would be IPv6, the successor to IPv4. However, the feeling among some industry watchers is that the amount of IPv4 equipment installed means that it will be some time before there is a general move to version six, if ever.
"There is a legacy of how everything has been built up," said Richard Proctor from Waveney Consulting. "There is too much equipment that won't work with version six. The main telecoms networks will be some hybrid of version four."
He said he could only see version six being used in closed environments, such as within a private network. For the main network he said version four would be improved and expanded.
"Version six will disappear into the distant future," he said. "There is no evolutionary route to version six."
IP over what?
As for what the IP will be running on, today ATM is the obvious choice but this will be migrating to MPLS in the near future to achieve the necessary quality of service. MPLS stands for multi protocol label switching and can bring ATM-like quality of service and traffic management features to IP networks.
A lot of existing equipment that was not designed to work with MPLS has been tweaked to do so. However, much of this is not capable of providing full traffic management capabilities, which means that a move to MPLS will involve a lot more equipment being installed. In the short term, though, MPLS is not a complete standard and many companies have their own proprietary versions. A potential standards nightmare could take a few years to sort out.
"When MPLS is fully implemented, it will be good," said Proctor. "But MPLS is not a finished job yet. In three to five years, MPLS will be able to do what it is supposed to."
BT is also looking at Ethernet as an alternative to ATM to provide scaling and flexibility. A key factor is to offer controllability to other service providers who will use the network.
"My system architect colleagues are looking at where to put the control, whether in the MPLS layer or the Ethernet layer," said Angus Flett, director of product management at BT Wholesale. "The great thing with MPLS is that it allows you to set up virtual channels and guarantee parcel performance.
But at the end of the day, it is still just a best-endeavour network."
What about optical fibre?
On broadband in general, the speed at which developers are pushing the limits of copper with ever-faster flavours of DSL has slowed down the roll out of optical fibre. The predicted dates at which there would be fibre to the home or at least fibre to the kerb have been and gone many times, and these days even the best pundits wave their hands and shrug their shoulders to avoid naming the day.
"Fibre to the kerb in this country will probably never happen because the cost would be astronomical," said Proctor. "We will see fibre to the green box on the street and then DSL from there. This will involve updating junction boxes but not digging up the streets. Fibre to boxes is starting to happen and will be widely available in five to ten years."
Even BT is only rolling out fibre on a customer-by-customer basis as economics dictate. And Flett acknowledged that, with the progress on copper, it was unlikely that fibre would be economically viable in a big way for some time.
"The ability of the guys at Martlesham (a BT research laboratory) to get copper networks at higher speeds is incredible," said Flett. "I am not sure it is a big issue now on whether we will replace copper with fibre everywhere until we have exhausted the technical capability of copper."
Likelihood of all-digital?
And so to 21CN, BT's big plan to create an all-digital network based on IP and offering various options for its customers.
The company is taking the work seriously and has earmarked £10bn of investment over the next ten years starting with a pilot programme in Cardiff. During the second half of 2006, existing voice, broadband and Ethernet services in the area will be migrated to the new network.
"A fair proportion of the £10bn will be spent on moving from a historic architecture to a more integrated platform," said Flett. "We want a network with greater economy and efficiency."
About 350,000 customers will be involved in the pilot including many served by other telephone operators, internet service providers and mobile phone companies.
"It is a move away from the existing telephone exchanges," said Proctor.
"Everything will be digital. It is a big leap, but it was going to come sooner or later. It will be everything over IP at the core even if the end user doesn't realise it."
Flett agreed. He said: "We want to move legacy voice onto an IP environment.
The users shouldn't notice the difference."
Part of this will be moving the architecture to being soft-switch based.
This will allow the development of new services and capabilities that would be too expensive on existing networks because it would involve changes to every switch throughout the network.
Proctor said he hadn't seen any sign of other operators in the UK following a similar route and said the only likely one would be NTL. NTL was asked about its plans but said no spokesperson was available.
Flett, though, said that the other operators would benefit from 21CN because they were also customers of BT and used its infrastructure.
"From a wholesale perspective, our customers are also probably our competitors," said Flett. "That is a very positive thing. The likes of NTL, Cable & Wireless, Energis and so on are all our customers. We want them to be able to integrate their applications seamlessly into ours. That is part of being a good wholesaler."
Possibility of 100% coverage?
Meanwhile, BT still has the difficult issue of getting broadband to that final 15% of users who live too far away from their local exchanges to make ADSL workable. Part of that problem is being solved with repeaters that can extend the reach of ADSL, which should take coverage to 95%.
"The final 5% will be really difficult," said Proctor. "This is where users are really remote or on really poor quality cabling."
One answer would be to use wireless broadband technology. This would let the network expand without putting in an expensive infrastructure.
Wireless also is likely to spread into other areas as a way that rival operators can come in and compete with BT without using its wired access.
But Flett said: "We are looking at wireless broadband in the way we are looking at all technologies, but there are no immediate plans to deploy it right now on a large scale."
