21CN
What is a NGN?
An NGN is a broad term used that describes the evolution of a new generation of communication infrastructure in the UK. At the heart of this technology is an Internet Protocol (IP) based packet technology network. The use of this technology is enabling multiple services such as voice, Broadband, TV on demand and other value added services to the end-user.
NGNs are operated by communication providers (CPs), which include companies such as BT, Cable & Wireless, Talk Talk and SKY to name but a few. Whilst each of these CPs may operate their own network (or sometimes purchase services from each other) there is the need to interconnect to each other and equally important, the ability to interface to the legacy network (the current TDM phone network used in the UK). The most well publicized NGN is that of BT’s 21CN, which is explained below.
What is 21CN?
BT is upgrading its existing telephone network to a “next-generation network” (NGN). BT is using the term “21CN” for this. Some of the key facts are as follows:
- The 21CN network uses a Digital Internet Protocol (IP) based network.
- The 21CN core network has already been upgraded. Ultimately this will result in the replacement of equipment in 5500 BT exchanges across the UK.
- The migration of voice & broadband lines to 21CN was planned to include circa 30 million PSTN / ISDN & and 8 million broadband lines. These plans have been dramatically scaled down following a strategic review.
- The migration to 21CN will result in wide availability of high speed broadband access, including a super fast ethernet service.
- 21CN will provide a UK NGN platform for other comms providers.
Customers will be “migrated” from the existing telephone network to 21CN lines over the coming years. Being a digital IP system, there will be some fundamental changes in the operation, which include delays in transmission of data and the effects of interconnecting other NGN providers. Both of these can impact on security equipment as the transmitted signals have a dependency on time between the communicating transmitter (the signaling device at the customers premises) and the transceiver unit (the receiver at a monitoring centre).
Other communications providers are making similar changes to their networks so you may be affected even if you do not use BT.
What is the latest situation with the 21CN migrations?
BT has completed its initial “Pathfinder” migration of approximately 65K PSTN lines in the Cardiff area to 21CN in Spring 2009 and was expected to announce details of the migration of a further 275K PSTN lines in the Cardiff area for later this year.
Following a strategic review of its NGN business, BT announced its intention to withdraw plans to mass migrate both PSTN and ISDN lines to 21CN. Migrations to 21CN will now only be based around customer demand and exchanges where equipment is reaching the end of its life.
Whilst this change is relevant to the "voice" element of the mass migration (where the majority of comms devices operate) the broadband aspect will continue apace.
A statement from BT regarding the outcome of their strategic review can be downloaded by clicking here.
What has BSIA done to assess the impact of this change?
BSIA has worked closely with BT over the last few years, since the emergence of 21CN was made known to us. Through initial testing of security products on the “simulated” network, and then on a “live” 21CN network, we have been able to understand how the effects of this change can impact on equipment.
Through our manufacturers we have produced a security equipment test plan, which provides a rigorous sequence of tests that covers the various signaling formats used in the Industry. The tests are conducted at the BT test facilities In Swansea, with specialist equipment provided by BT.
The BSIA test plan can be downloaded by clicking here.
Note: The BSIA Fast Format guide has recently been reviewed as a result of 21CN and NGN activity and is now available. Previous versions of the guide are available on request. The BSIA Fast Format guide can be downloaded by clicking here.
Through the testing we have conducted to date, and the knowledge we have gained through discussions with BT, Ofcom and other comms providers, we have been able to call on a wealth of experience and develop a risk based assessment of the impact of 21CN on security equipment. This assessment evaluates the likelihood of something happening and the consequence it delivers. The output of this assessment has enabled us to provide a clearer message to end-users, installers, monitoring centres and manufacturers. BSIA members have been briefed on the risk assessment outcome.
BSIA continues to raise awareness of NGN and call routing issues through its regional and Technical meetings, along with seminars and events. We also offer a support service to our members who have / are experiencing signaling failures of this nature.
How do I know if my equipment is at risk of failure?
All BSIA comms equipment manufacturers have attended the BT facility in Swansea and tested their core products against the BSIA test plan. The results of these have been published on the BSIA website.
The test results can be downloaded by clicking here.
The test results focus on the main potential failure mode for 21CN, which is additional network delay. They also provide a 21CN compatibility test.
Reading the results on their own may not provide a straightforward answer to whether certain equipment is at risk, as there are two other factors that can affect the overall delay of alarm signals; these being the type of receiving equipment and the type of network on which it is transmitted. To assist with this, BSIA has also produced a web based “risk calculator” which allows you to enter the two fundamental values under consideration, those being the communicator delay and the receiver processing delay. Once these values are entered, a graphical representation is produced showing you the potential risk of failure on each of the known network routing configurations.
The web-based calculator is available by clicking here.
NB. Whilst every effort has been made to ensure that the results are full and reliable, the BSIA cannot accept any liability for the accuracy of the results or responsibility for any reliance upon the results. The tests which gave rise to the results were dependent upon British Telecoms technical equipment and were carried out by each contributing manufacturer themselves.
Where are we with fibre connectivity?
With the upgrading of the 21CN core network, BT is enabling fibre to the Cabinet (FTTC) and fibre to the premises (FTTP) through its exchanges. BT has accelerated its FTTC roll out (a service known as BT Infinity) which will enable faster broadband access to end-users, whilst maintaining the copper element of the voice network. Current understanding is BT is targeting a 40% coverage of high speed broadband access by 2012. Compatibility testing carried by BSIA on BT’s live FTTC network has seen no issues for existing comms devices.
BT fibre to the Cabinet update (FTTC)
BT Openreach has recently announced its intention to enable up to 786 of its 5500 exchanges for Super Fast Fibre Next Generation Access (NGA) to over 4 million premises; its target to pass 66% of premises by 2015 (16 million in total). The rollout plan will include FTTC and Fibre to the premises (FTTP).
BT fibre to the premises update (FTTP)
BT Openreach has recently announced its intention to launch its voice fibre access solution across the UK during 2012. BT is investing £2.5 billion over the next two-years on the fibre rollout launch. Whilst not on the scale of 21CN, it has the potential to disrupt communication devices (CPE) connected to alarm systems.
BSIA are in discussion with BT Retail with regards to a suitable format for testing CPE, which is available for manufacturers by clicking this link.
Is the BSIA working with other Next Generation Network communication providers?
Since the Ofcom consultation, a communication industry forum called NGNuk has been established. This forum comprises of Communication providers and Ofcom and its primary role is to address issues with NGN and NGA (Next Generation Access) across the UK. BSIA has already established a link with this forum and is addressing the needs of our members, especially around fibre access, testing and network understanding. Members have received personalized presentations by NGNuk to raise awareness of the issues industry faces with the emrgence of NGNs.
Following our earlier discussion with NGNuk with respenct to the Ofcom consultation last year, we were delighted to receive the NICC guidance document; NICC ND 1431: Guidance on CPE Compatibility on NGNs and NGAs. This long awaited document assists manufacturers in the design and operation of voice band detection and voice CPE and provides compatibility testing of such CPE against NGN and NGA networks.
BSIA is still seeking an answer to the maximum network delay expectations, which are not confirmed in the above document; a fundamental issue we have been campaigning to address over the past few years.
BSIA has concluded some earlier testing with SKY on its Voice Broadband Network (SVBN), which is an IP technology based NGN. Whilst identifying an issue that affected digital communicators, testing revealed the problem, and SKY reconfigured their software to resolve the issue. Whilst this is good news, it does highlight the problem with NGN providers changing their network designs, without consultation with industries like ours.
BSIA guidance documents
The BSIA has produced guidance for ARCs, Installers and manufacturers with regards to 21CN and these are available to members of the BSIA on the BSIA members website. We have also produced a "User Guide" which gives basic advice about the changes to the UK telephone system and how it may affect your burglar alarm. This guide can be downloaded by clicking here.
Last updated June 2011
