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Last updated: 09 November 2010
This section gives you the Five Guiding Principles which provides focus to enhance the resilience of communications, and advice on enhancing the resilience of everyday telecommunications, such as terrestrial (fixed line) and cellular mobile telecommunications, as well the use of satellite telecommunications.
1. Look beyond the technical solutions at processes and organisations. When considering resilient telecommunications considerable emphasis tends to be placed on the technical solutions (such as pagers or mobile telephones). However, the processes used in communicating (such as agreed protocols that make conference calls work smoothly) and the way in which responders organise themselves to respond to emergencies should command equal attention and recognition that none of these three components should be considered in isolation. There is no silver bullet to enhancing the resilience of communications.
2. Identify and review the critical communication activities that underpin your response arrangements. In order to focus the selection of technical solutions on the need to communicate it can be helpful to indentify the critical communication activities that underpin response arrangements to emergencies. An 'activity' is essentially 'what you do' (for example, it could involve a designated person establishing contact with another designated person and exchanging particular information). Critical activities are those that are essential to the effectiveness of response arrangements. For these activities, the focus can be maintained on the need to communicate by assessing the basic 'technology free' communication requirements (such as sending or receiving specific information rather than just 'phoning someone). For further advice see Towards Achieving Resilient Telecommunications: Interim Guidance [PDF, 8 pages, 163KB].
3. Ensure diversity of your technical solutions. For critical activities, the technological means to carry out the communication can then be considered with the objective of increasing overall telecommunications diversity. However, it can be difficult to assess how truly diverse technical solutions are because of the inherent dependency of one technical solution on another. For example, public mobile (cellular) networks are dependent to varying degrees on core communications networks (that deliver land-line telephone services) - failure or degradation of core networks can affect mobile services. Further information on our telecommunications networks can be found in An introduction to the structure of UK telecommunications sector [PDF, 422KB, 34 pages].
4. Adopt layered fall-back arrangements. No technical solution is going to be available all the time. Availability is a consequence of the reliability of the system (associated with faults, and their repair) and the ability to cope with congestion (resulting from excessive demand). Adopting a layered fall-back approach to selecting technical solutions helps mitigate unavailability. A fall-back solution may not necessarily provide the same 'richness' of communication, such as voice telephony falling back to a pager. For further advice see Ensuring Resilient Telecommunications: A Survey of some Technical Solutions [PDF, 37 pages, 480KB].
5. Plan for appropriate interoperability. The NPIA hosts an interoperability programme [External website] that is aimed at to increasing public and personnel safety through improved multi-agency communication and co-ordination.
An important step in enhancing resilience is to help ensure that responders avail themselves of the best possible value from commercial telecommunication services. Steps have already been taken to raise awareness through newsletters, workshops and interim guidance. One of the messages to come back from our engagement with stakeholders was that there is a need for clear and concise advice to assist particularly smaller organisations appreciate the range of technologies available, their strengths and weaknesses, and the steps that might be taken locally (often at little cost) to enhance resilience.
The Centre for the Protection of National Infrastructure (CPNI) [External website] has produced guidance on enhancing the resilience of telecommunications networks and services [External PDF].
Relevant courses at the Emergency Planning College [External website] have been reviewed and extensively revised to support Telecommunications Sub-Groups that have been established to take forward the agenda of enhancing the resilience of telecommunications in each Local Resilience Forum (LRF) area.
The Electronic Communications Resilience and Response Group (EC-RRG, previously TI-EPF), is established to ensure the availability of Electronic Communications infrastructure for the UK and provide an industry emergency response capability through the ownership and maintenance of the National Emergency Plan for Telecommunications. Further details of the Group can be found in its Terms of Reference. The Group has an arrangement in place, referred to as NEAT (the National Emergency Alert for Telecommunications), which supports co-operation across the industry in response to emergencies affecting telecommunications in the UK. Membership of the Group embraces Category 2 Telecommunications Responders (as defined by the Civil Contingencies Act (2004)).
In view of the importance of communications in responding to emergencies Telecommunications Sub-Groups are to be established, as appropriate, within the existing resilience infrastructures. Each sub-group will be responsible for considering all aspects of communications, including the technical means, and how resilience might be enhanced within their area.
Terrestrial telecommunications networks are sometimes referred to as ‘fixed line’ or ‘land line’ infrastructures because much of the physical infrastructure consists of copper (regular wire and co-axial cable) and optical fibres. These networks are used to deliver regular services such as voice telephony and ISDN. The physical network used to deliver these services can be considered to consist of core networks and access networks.
Core networks, which are sometimes referred to as ‘backbones’, are high bandwidth transmission systems connecting together geographically dispersed locations (also variously referred to as ‘nodes’ or ‘points of presence’) which, for voice services, are commonly called ‘telephone exchanges’.
Access networks, often referred to as the ‘local loop’ or ‘last mile’, provide connection between the exchange on the provider’s network and the customer’s premises.
Background information on the role that these structures play in the resilience of UK telecommunications networks can be found in:
and
Core networks generally offer a high level of resilience, however, the ‘last mile’ connection to the customer is invariably the weakest connectivity link. Strategies to enhance the resilience of the ‘last mile’ connection include gaining assurance from your provider that the geographic cable routes and points of presence are physically separate and that arrangements provide diversity of connection in the event of service degradation of failure.
Unless assurance is gained that telecommunications services are delivered to your premises over more than one distinct geographic route you should assume that the connection takes a single path from the point of presence on the providers network to your premises. Outside the customer’s premises, connections are vulnerable to hazards such as road works disturbing cables in ducts or, in rural areas, extreme weather washing out buried cables or bringing down overhead lines. The consequences of these hazards can be mitigated by having more than one physical connection to your service provider’s exchange. This arrangement of diverse routing can be further enhanced by the provision of duplicate connectivity from different points of presence on your provider’s network to different parts of your premises – a scheme that is sometimes referred to as ‘dual parenting’.
Obtaining telecommunications services from more than a single supplier may not enhance resilience. Largely as a consequence of the structure and maturity of the telecommunications industry in the UK, it can be very difficult to gain assurance that two telecommunications links, provided by different suppliers obtained for the purpose of providing resilience, do provide resilience through diverse geographic routing and logical connection. Networks are increasingly becoming virtual with services being delivered over shared infrastructures – for further information see Ensuring Resilient Telecommunications: A Survey of some Technical Solutions [PDF, 37 pages, 480KB].
Does your corporate telephone exchange have stand-by power? While exchanges on the provider’s network generally have robust stand-by electrical supplies – typically being able to work for at least five days from diesel generators – arrangements for a PBX or PABX (Private Automatic Branch eXchange) are the customer’s responsibility.
Wireless handsets connected to fixed lines are dependent on grid-distributed electricity. Predominantly in the domestic environment, very basic telephone equipment wired into the access network is typically powered by the network. In the event of a failure of the local electricity supply the equipment will continue to function as exchanges have robust back-up power arrangements. Handsets that are connected by wireless to a base station (commonly using DECT technology) that is in-turn wired to a ‘wall socket’ are not powered by the network. In both the domestic and corporate environment DECT technology is increasingly being used to provide wireless access for digital portable telephones.
Equipment connected to ADSL Broadband Internet that is delivered over a regular telephone line will require back-up power supply arrangements in order to work if local power fails. While the Broadband and any telephony services that share the line are resilient in the event of a local power failure, additional ‘customer side’ equipment such as a ‘hub’ (containing a modem and router) and computers will require back-up power arrangements to ensure resilience. In the short-term this could be provided by an uninterruptible power supply (UPS) or batteries.
With ISDN services the service provider does not provide supporting power. In order to ensure resilience in the event of local power failure, ‘customer-side’ back-up power arrangements need to be provided for any line termination or interface equipment (usually located where the lines enter the customer’s premises) and for subsequent equipment connected to the service (such as modems).
Review your requirements for resilient telecommunications and interact with your provider. The CPNI [External website] has published the Good Practice Guide for Telecommunications Resilience [External PDF] which provides a helpful starting point from which to address resilience. The Guide contains a risk-based methodology to assist in clarifying business requirements supported by a “Self Assessment Questionnaire”. This process is designed to enable resilience-enhancing dialogues to be established with your telecommunications suppliers. To assist in promoting a meaningful dialogue the Guide offers a list of “Twenty questions to ask your providers”.
Consider arrangements to redirect calls at your provider’s exchange. Equipment can be installed [PDF, 3 pages, 366KB] in your provider’s exchange to redirect in-coming calls to alternate locations in the event that these cannot be forwarded to your premises or, in situations where you are unable to accept them. The type of events that preclude completion of an incoming call include failure of the connection between your provider’s exchange and your premises or failure of the private exchange. Redirecting incoming calls at your provider’s exchange enables business continuity when, for instance, your premises becomes uninhabitable - possibly as a consequence of a major fire or flooding; inaccessible - as a consequence of a Police cordon or, when staff are unavailable to answer the calls – possibly resulting from transport difficulties. The equipment installed in your provider’s exchange is usually programmed in advance to provide call re-direction of DDI (Direct Dial Inward) calls – those starting with 01 and 02 - to alternate locations. These arrangements are then activated with a single call, such pre-planned response arrangements can be customised on ‘the fly’ for unforeseen circumstances.
Ensure that your private exchange has resilient electrical power. Unless your private exchange is provided with a back-up power supply, failure of electricity at your premises will result in failure of telephony equipment connected to the ‘customer-side’. Usually, an uninterruptible power supply (UPS) is installed to provide uninterrupted service in the event of short term loss of power – usually under an hour. For greater resilience, this can be augmented with diesel generation. Facsimile and other equipment may also need to be connected to the back-up supply.
Test back-up power supply arrangements. Untested back-up power supply arrangements invariably fail on demand – batteries and generation equipment either fail to take full load or do not function for the designed time. Confidence in back-up arrangements should be sought through routine stress-testing carried out under realistic load conditions and for a time that tests site specific arrangements. Only under these conditions do problems such as blocked air and fuel filters and contaminated fuel become apparent. For well maintained back-up generation systems practical experience indicates that the likelihood that they fail on demand lies between one in 70 and one in 200. With this evidence it seems worth considering having an additional layer of ‘fast fix’ arrangements in place, such as a call-off rental contract.
Do not rely on GTPS as the cornerstone for providing resilient telecommunications. The current fixed-line privileged access scheme has been used very rarely, largely as a consequence of the draconian consequences of invocation. The core telecommunications networks in the UK are to be renewed. In view of the gradual refresh of the old networks, over which the existing scheme works, we are not encouraging further take-up of GTPS. The new scheme will be called the Fixed Telecommunications Privileged Access Scheme, or FTPAS. FTPAS will be made available as the new networks are rolled-out.
Public cellular mobile telephony has played an important role in responding to recent emergencies. However, both society and the responder community has embraced the convenience of mobile telecommunications often without pausing to appreciate the inherent resilience issues.
Geographic coverage is a widely appreciated limitation of public cellular mobile telephony. Selection of a service provider is frequently made on geographical coverage relevant to customer needs. Selection can be informed using interactive maps available on service providers' websites. Additionally, Ofcom (the independent regulator and competition authority for the UK communications industries) publishes coverage maps for 3G networks [External website]. In use, handsets provide immediate and visual indication of signal strength. Network coverage is closely mapped to population density - in rural areas coverage can be non-existent or very patchy where a dominant supplier may not exist.
Having multiple SIMs available for a handset might cause problems. Many organisation's business continuity plans seek to mitigate shortfalls with coverage and congestion by issuing responders with SIMs obtained from several different UK network operators. Handsets can be locked to a particular service provider preventing SIMs from other operators from working in the handset.
SIMs issued by international operators have their own drawbacks. International SIMs can allow roaming onto available UK networks, thereby taking advantage of available coverage and network capacity. However, UK network operators only allocate limited capacity for roaming users and permission for a handset to roam is sought by the handset from the operator issuing the SIM. This may require access to international telephone circuits. Following the bombs in London on July 7th, 2005 one technique used by network operators to manage the huge increase of inward calls to the UK was to request constraints to be applied on international circuits. In addition, out-bound calls from the handset to UK numbers will have to be prefixed with the UK international access code and in-bound calls to the handset will have to be prefixed with the international code applicable to the SIM. Both activities could result in confusion, particularly in times of stress.
The capacity of public mobile telecommunications networks is finite and they are not sized for an abnormally high level of demand. Networks can become overwhelmed when presented with a high concentration of calls such as those that occur immediately after a major incident and capacity constraints are often an issue at other times such as at one minute past midnight on New Year's morning. Here, the difficulty in 'getting through' is often incorrectly attributed to the called party already receiving a call.
Mobile networks are highly dependent on the availability of grid distributed electricity. In the event of local power failure, network infrastructure is designed to revert to back-up batteries. After around an hour on battery supply services become increasingly degraded.
While 'Pay as you Go' services may appear attractive, telephone numbers can be reallocated if the handset has not been used for a period of time. While this may not present any difficulty for out-going calls if contact lists are not regularly maintained the handset may be inaccessible to incoming calls.
Mobile Privileged Access Scheme (MTPAS). When a major incident has been declared, access to a cellular mobile network can be enhanced through installing a special SIM card. The scheme which manages the distribution of these special SIMs to the responder community's entitled users is called Mobile Telecommunications Privileged Access Scheme, or MTPAS. Privileged access may not work with SIMs issued by overseas service providers that require international access code (00 44) from the UK for out-going calls to UK numbers. However, international SIMs compatible with the UK national numbering system do respond to MTPAS activation.
Keep calls as short as possible. In the event of an emergency, capacity on mobile networks is greatly enhanced by keeping calls as short as is possible - particularly in the hours immediately following the event. For example, following the bombs in London on 7 July 2005 at 08:50, by 10:00 voice traffic on both fixed and mobile networks and SMS traffic on mobile networks had started to increase rapidly, reaching a peak at around 11:00. Typically fixed telecommunications service providers were offering ten times as many calls as normal to mobile network operators. The picture was very different on the fixed infrastructure, typically the number of attempted calls increased by 75% compared to the previous week. On mobile networks, the pattern of use changed - the average call duration rose by a factor of four from 2.5 to 10 minutes. The number of SMS sessions typically increased by a factor of three and at peak demand, the delivery delay was typically between 90 – 150 minutes. By 14:00 fixed line traffic had reduced to 20% above a typical day, tailing off by mid-evening. On mobile networks traffic back to normal by early evening.
When a mobile phone is used to make a call to the emergency service numbers (999 and 112) and the provider's network is unavailable, the call will roam onto alternative network that has the best signal in the area. This facility will be of particularly benefit in rural areas (announced by Ofcom [External website] the communications regulator on 15 October, 2009).
Commercially available satellite communications assist in enhancing the resilience of telecommunications through diversification and can be made available to responders through a centrally-negotiated Catalogue.
Through the network of Regional Government Offices, Cabinet Office has made available a centrally negotiated Catalogue of commercial satellite communications equipment and training. The most popular system has been the Inmarsat BGAN system. If you have satellite communications equipment, please read Getting the best out of satellite handsets ordered through the catalogue [PDF 3 pages, 76KB].
UPDATE April 2009
Cabinet Office is no longer funding equipment and services from the centrally negotiated Catalogue. However, the Catalogue remains available to Public Sector organisations that wish to source, from their own budgets, equipment and services. Enquiries should be sent to: satcomms@cabinet-office.x.gsi.gov.uk
Inmarsat BGAN service - update January 2009
Inmarsat have recently posted additional information [External website] on the satellite movements posted earlier on this site. The information is highly relevant for continued use of Inmarsat BGAN equipment in the UK.
Inmarsat BGAN service – update March 2008
Inmarsat are to add a third satellite to their constellation. As a consequence they have scheduled movements of their existing satellites through November and December, 2008.
The effect of these movements will be that in Scotland and Northern Ireland there will be a five week period where BGAN coverage is unavailable. At lower latitudes, England and Wales should continue to have coverage. Further information is available from Inmarsat [External PDF]. This situation reinforces the need for diverse communications arrangements.
After the moves, the current choice of pointing your portable terminal at one of two satellites (one to the south west and one to the south east) will no longer exist. From the UK we will only be able to see a single satellite further south. However, this satellite will have a greatly increased angle of elevation above the horizon thereby providing improved visibility. If you currently site your equipment through a south west facing window you may need to find an alternative location facing south east. If your satellite capability is delivered through an antenna mounted on the roof of your building the antenna will need to be re-oriented. For those affected, our technology partners will be contacting you to arrange for this adjustment to be carried out for which you will see no charge.
Inmarsat training day - February 2008
Training was provided by Inmarsat for representatives of Telecommunications Sub-Groups to provide a greater understanding of the system and equipment. The training included the following presentation:
Additional links from the Inmarsat website:
UPDATE April 2009
Cabinet Office is no longer funding the satellite handsets connected to the Globalstar network. Enquiries regarding handsets made available by Cabinet Office should be sent to: satcomms@cabinet-office.x.gsi.gov.uk
UPDATE June 2008
In 2005, Cabinet Office provided satellite handsets connected to the Globalstar network and call time for use in training and responding to emergencies to a community embracing Category 1 responders. Cabinet Office has extended these arrangements to the end of financial year 2008/9. The following manuals for the Telit Sat 550 handsets are availble:
The Globalstar service is delivered by a constellation of low-Earth orbit satellites that move across the sky. Although experience of the Globalstar service has been mixed, largely as a consequence of technical problems, the satellites launched by Globalstar in 2007 have improved the service and more are planned. Holders of Cabinet Office Globalstar handsets are encouraged to continue to use them for training and response for which Cabinet Office will cover the cost of additional calls. Advice on using the service can be found on the Globalstar website [External website]
General enquiries: Cabinet Office, 22 Whitehall, London SW1A 2WH.
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