Business cost consultants focusing on energy, water and telecommunications services
Next Generation Networks - a technology update by Ian Cobley of Frontline Network Services
29 August 2007
In June 2004, BT announced the most radical shake up of its nationwide network in the 25 years since the first digital switches were introduced. They are transforming their core network from old circuit-switched, narrowband technology to modern IP (Internet Protocol) broadband transmission, while leaving the copper access networks in place.
This new converged network (BT is calling it 21CN or 21st Century Network) will transform all calls into voice over IP (VoIP). It will be the first time a PSTN (public switched telephone network) has been ported to IP.
Usually 'next-generation network' is used to describe the backbone that communications companies are rolling out for their voice and data services. Next-generation networks are already transforming the way businesses communicate today, and will ultimately revolutionise how communication services are delivered in the future.
The majority of traditional voice and data networks are underpinned by multiple network platforms that employ a variety of different transmission protocols. In comparison, next-generation networks (NGNs) take a converged approach to network services. All types of network traffic - whether it's voice, video or data - are transmitted on a single, coherent platform, based purely on a single common protocol. Working on an all-IP platform, BT's 21CN will ensure that voice traffic is treated the same way as data, and carried as a series of digital signals between caller and recipient.
BT's plans for its 21st Century Network, based around a fully converged IP infrastructure, asserts the commitment all operators are demonstrating in the acceptance of IP as the main protocol for networks now and in the future. However not all are taking the same approach to implementing their versions of NGN.
Opal Telecom a subsidiary of Carphone Warehouse plc, is a long standing traditional voice services operator, the 4th largest in the UK after BT. Utilising the resources of Carphone Warehouse Networks, Opal is well on the way to upgrading its traditional network. They have their Gigabit Ethernet core infrastructure in place and with Sonus softswitch technology implemented for voice prioritization over MPLS they have over 300 million minutes a month already on the new network. Their aim to have executed their network roll-out well in advance of BT is on course.
In tandem with the building of the NGN, Opal are taking advantage of the Local Loop Unbundling (LLU) of BT's network. LLU is a process whereby the incumbent operator, BT, makes its local network (the copper cables that run from customers' premises to the local telephone exchange) available to other Local Loop Unbundling Operators (LLUO). The cables are physically disconnected from BT and reconnected to the other LLUO. The LLUO is then able to upgrade the individual lines using DSL technology to offer services such as high speed always on Internet access direct to the customer.
In contrast to other LLUO's focusing on broadband, Opal's intention is to pursue a fully unbundled strategy, enabling them to take physical control of the switched voice line as well as the broadband connection.
One of the more significant building blocks of the new BT network will be the deployment of a multi-capability box in local exchanges that will replace the work of much specialised equipment, the Multi Service Access Network (MSAN). MSANs will be able to bring voice, IP, Ethernet, ATM, SDH, ISDN and just about any other fixed telecom technology into the same bit stream.
By only fitting MSANs into BT exchanges Opal's full unbundling strategy enables them to accept calls in whatever format customers send them - standard analogue voice, data or VoIP - relieving customers of the need to ensure compatibility. A single bill will cover both voice and broadband. In the coming years, Opal are looking ahead to offer "triple play" (including mobile services) and "quadruple play" (IPTV and VoD).
While IP has been adopted as the transmission mechanism for next-generation networks it is not the whole story. THUS plc has made the transition from a regional to major national, business-focused data and telecoms service provider in the UK. In the process it was one of the first operators to build an NGN. First fully deployed in 2003, the THUS network now comprises 10500 km of fibre optic cable with more than 190 points of presence throughout the country and 15 metropolitan area networks in the UK's most populous areas.
The core optical network uses DWDM (Dense Wavelength Division Multiplexing) technology to provide scalability to many hundreds of gigabytes of bandwidth, in line with growth demand. In addition, THUS has deployed a truly converged network based on MPLS technology.
Multi-Protocol Label Switching (MPLS) is the ideal platform to carry IP-based voice, video and data traffic across a converged infrastructure reliably. It enables a variety of services that can provide flexible, customisable any-to-any network connections to multiple sites as well as Quality of Service (QoS) prioritisation for different service types. MPLS operates as a separate layer to the specific networking protocol, such as Internet Protocol (IP). It works by adding its own envelope label information to each packet of data that is sent over a network, ensuring that it gets routed as quickly as possible, no matter what type of data it happens to be.
As early as 2004, THUS began deploying softswitch technology for Voice over IP (VoIP) services. THUS has installed Call Server technology in order to support a full suite of VoIP and multimedia applications. This investment not only provides basic SIP server capabilities, but is also a carrier-class implementation that will support all future converged voice services. Softswitch technology offers the same quality of service as customers have come to expect in the legacy telecoms world, but also offers the performance, flexibility and functionality that can only be associated with the next-generation era.
The other component that contributes to converged, end-to-end communications is the ability to extend the benefits of the core network all the way to the customer's premises.
THUS has a wide portfolio of access services, ranging from dial-up to Ethernet, which can be used according to business needs. Customers can select from a range of access types, and still benefit from converged communications and applications. For example, for a next-generation MPLS virtual private network, THUS can offer access options ranging from fibre to Leased Lines, supporting Ethernet, MPLS or IP. Even dial-up or DSL can be used as an effective way to extend the reach to peripheral offices or mobile/remote workers.
Whether taking the BT, Opal or THUS approach to deployment, NGN is a term that represents many perspectives on the future of communications. The current emphasis is on network technology, but this is only the beginning, and the real revolution will be witnessed once the boundaries between networks and applications are removed.
Fundamentally, because all voice calls on an NGN become IP traffic, eventually there will no need to have to think about what type of device is being used to connect to an IP network. It could be a mobile phone, desk phone, or a computer - but will have exactly the same number. The system will be based on software rather than hardware, so a call is just that, no matter where located or what device is being used.
Eventually you won't have to call someone on their landline, then call them on their mobile when they're not available, then try to connect via instant messaging if they're out of range. You will just be able to say, 'I want to get in touch with Steve,' and have the system work out the best method of contacting him.
If you need more information or have a specific query as a result of reading this article please, in the first instance, contact Steve Bellerby on 01952 825 820.