IPTV Feature Article
July 15, 2009
IPTV Over Copper: A Valid Business Proposition?
By Bob Emmerson, TMC European Editor
Fiber to the home is the 100 Mbps end game, but it’s a forklift upgrade that takes time and money. Regular VDSL2 delivers 20 Mbps over copper and this enables the delivery of robust triple-play services, but the bandwidth gap is significant. Push it up to 50 Mbps and the case for copper starts to shine.
Network operators can deploy fiber in various ways. They include fiber to the node (FTTN - a cabinet that serves a neighborhood comprising up to several hundred customers); fiber to the building (FTTB -a small node serving an apartment building); and fiber to the home (FTTH). The latter requires a dedicated fiber to every home, resulting in a significant investment having a long ROI.
Unlike fiber to the home, FTTN and FTTB only deploy fiber for part of the last mile (up to the cabinet, curb, or building). After that VDSL2 is used to deliver IPTV (News - Alert) and triple play services over the copper access network that was originally deployed for plain vanilla telephony.
Therefore the combination of FTTN/B and VDSL2 access architecture represents a cost-effective, expedient way to deploy triple play services, i.e. multiple IPTV streams, VoIP, high-speed Internet connectivity and HDTV.
Unless the copper is old or the lines are long, there is no problem with transmission speeds of 50 Mbps and higher. On shorter loops, which are typically found in FTTN/FTTB deployments, the VDSL line card capacity (and the switching capacity of the multi-service access platform) determines the bitrate that can be delivered to each subscriber.
Unlike fiber to the home, FTTN and FTTB only deploy fiber for part of the last mile (up to the cabinet, curb, or building). After that VDSL2 is used to deliver IPTV (News - Alert) and triple play services over the copper access network that was originally deployed for plain vanilla telephony.
Therefore the combination of FTTN/B and VDSL2 access architecture represents a cost-effective, expedient way to deploy triple play services, i.e. multiple IPTV streams, VoIP, high-speed Internet connectivity and HDTV.
Unless the copper is old or the lines are long, there is no problem with transmission speeds of 50 Mbps and higher. On shorter loops, which are typically found in FTTN/FTTB deployments, the VDSL line card capacity (and the switching capacity of the multi-service access platform) determines the bitrate that can be delivered to each subscriber.
VDSL2: Facts and Figures
VDSL2 (Very High Speed Digital Subscriber Line 2) is an access technology that exploits the existing infrastructure of copper wires. It can be deployed from central offices, from fiber-fed cabinets located near the customer premises, or within buildings.
It was designed to support the wide deployment of Triple Play (News - Alert) services such as voice, video, data, high definition television (HDTV) and interactive gaming.
VDSL2 (Very High Speed Digital Subscriber Line 2) is an access technology that exploits the existing infrastructure of copper wires. It can be deployed from central offices, from fiber-fed cabinets located near the customer premises, or within buildings.
It was designed to support the wide deployment of Triple Play (News - Alert) services such as voice, video, data, high definition television (HDTV) and interactive gaming.
Multi-Service Access
IP DSLAMs (Digital Subscriber Line Access Multiplexers) that have the requisite functionality for triple play services are called MSANs (Multiple Service Access Nodes). In Alcatel-Lucent (News - Alert) parlance they are known as ISAMs (Intelligent Service Access Managers).
These products employ different line cards that are used for the different services and access technologies, e.g. DSL, VDSL, copper and fiber. And while a technology purist may object, they are also the FTTN, i.e. they are the interface between the core network and the access network.
Raising the Rate
Regular VDSL2 delivers 20 Mbps. Back in 2004 an analyst at Heavy Reading indicated that this was the minimum figure needed for a compelling triple play offer. Alcatel-Lucent’s ISAMs, which employ 1Gbps line cards having 48 ports, have been delivering this rate since 2006.
The latest ISAM release (4.0) will employ a 100 Gbps switching matrix and 2.5 Gbps line cards, each of which has 48 ports. Do the math and you get a rate of just over 50 Mbps per port/subscriber. Delivery of what the company says will be the first 50 Mbps VDSL2 line card is scheduled for 1Q 2010.
Is it Enough?
You can never have too much bandwidth but of course you have to look at the deployment cost of copper versus fiber and the return on investment.
IP DSLAMs (Digital Subscriber Line Access Multiplexers) that have the requisite functionality for triple play services are called MSANs (Multiple Service Access Nodes). In Alcatel-Lucent (News - Alert) parlance they are known as ISAMs (Intelligent Service Access Managers).
These products employ different line cards that are used for the different services and access technologies, e.g. DSL, VDSL, copper and fiber. And while a technology purist may object, they are also the FTTN, i.e. they are the interface between the core network and the access network.
Raising the Rate
Regular VDSL2 delivers 20 Mbps. Back in 2004 an analyst at Heavy Reading indicated that this was the minimum figure needed for a compelling triple play offer. Alcatel-Lucent’s ISAMs, which employ 1Gbps line cards having 48 ports, have been delivering this rate since 2006.
The latest ISAM release (4.0) will employ a 100 Gbps switching matrix and 2.5 Gbps line cards, each of which has 48 ports. Do the math and you get a rate of just over 50 Mbps per port/subscriber. Delivery of what the company says will be the first 50 Mbps VDSL2 line card is scheduled for 1Q 2010.
Is it Enough?
You can never have too much bandwidth but of course you have to look at the deployment cost of copper versus fiber and the return on investment.
Fiber services will typically deliver 100 Mbps, but current service offerings only need 20Mbps, which means that the end-user experience of triple play services over fiber will be virtually identical to those over copper. Therefore the business proposition is very simple: leverage the copper infrastructure and thereby generate triple play revenues today and obtain a relatively fast ROI. Relative, that is, to nationwide FTTH rollouts.
In the U.K., BT (News - Alert) recently announced that their rollout will be FTTN, with the final connection to the home being a VDSL2 service over copper. FTTH will be rolled out mostly in new green field areas as well as the Olympic Village that's being built outside London for the 2012 Olympic Games. In addition, BT says that about 90 percent of the fiber-based networks will be leveraging FTTN, while 1 million users will have FTTH.
Conclusions
The combination of FTTN and VDSL2 running at 50 Mbps represents a powerful, pragmatic solution that should enable operators to build a robust market for triple play services. FTTH will be the end game, but the ability to generate near-term revenues is clearly a business-like way to finance that investment, particularly in the current economic climate. Alcatel-Lucent estimates that the cost per subscriber of FTTN/VDSL is around one third of FTTH.
There are issues about line stability and the higher power consumption of VDSL technology. They have been addressed by Alcatel-Lucent and will be covered in a second article together with access network architectures.
In the U.K., BT (News - Alert) recently announced that their rollout will be FTTN, with the final connection to the home being a VDSL2 service over copper. FTTH will be rolled out mostly in new green field areas as well as the Olympic Village that's being built outside London for the 2012 Olympic Games. In addition, BT says that about 90 percent of the fiber-based networks will be leveraging FTTN, while 1 million users will have FTTH.
Conclusions
The combination of FTTN and VDSL2 running at 50 Mbps represents a powerful, pragmatic solution that should enable operators to build a robust market for triple play services. FTTH will be the end game, but the ability to generate near-term revenues is clearly a business-like way to finance that investment, particularly in the current economic climate. Alcatel-Lucent estimates that the cost per subscriber of FTTN/VDSL is around one third of FTTH.
There are issues about line stability and the higher power consumption of VDSL technology. They have been addressed by Alcatel-Lucent and will be covered in a second article together with access network architectures.
Bob Emmerson (News - Alert) is TMC's European Editor. To stay abreast of the latest news affecting the European market, check out Bob's columnist page.
Edited by Stefania Viscusi
