1. Delivering telecare services during the transition to “all IP”
Huw Saunders, Director, Network Infrastructure
16th October 2017

2. Agenda PSTN switch off – what is it and why is it happening?
Issues for current analogue “voiceband data” services including telecare
Ofcom’s work programme
Future “all IP” service issues

3. What’s the problem: PSTN “switch off” and replacement is now underway…..
Incumbent CPs have been looking to migrate from obsolete Public Switched Telephone Network (PSTN) systems for some time
Replacement strategies are centred on Voice over IP “softswitch” platforms
Initial migration strategies focussed on “emulating the PSTN”, broadly meaning to continue the use of traditional analogue transmission on existing copper networks.
Increasingly, focus is turning to “Voice over Broadband” (VoBB) or “derived voice”
With the near universal adoption of broadband for internet access and other services, this allows consolidation on a single access technology and will be the way forward in the UK. In some cases, this bearer may be a wireless rather than a fixed line connection
Many such systems are already obsolescent and support costs are increasing rapidly as both hardware and software are becoming increasingly difficult to maintain
Increasingly based on the standardised approaches of SIP and IMS, which offer multi-vendor support and easier interoperability and interconnection
This was the intention of BT’s 21CN programme before implementation problems became so great that they had to abandon the voice element of the project. This approach is, however, now being successfully adopted by some incumbents in other countries in Europe and elsewhere

4. The migration of separate voice service to just another application over broadband
When the internet first came along, it ran over telephone lines
(remember dial-up?)
Nowadays we have separate “bearers” for the internet and for the phone
Soon, phone calls will be carried over the same “bearer” as internet connections, as we move to “all IP”
Cable
Fibre
* Cable has a similar but not identical migration to DSL

5. Specific PSTN legacy “non voice” service issues that need to be addressed
PSTN replacement networks will not necessarily support services that rely on conventional end to end “POTS” delivery
In particular, DTMF tone transfer will be affected in ways that may make some security and care alarms malfunction - such problems will also extend to fax machines and other devices that use voice band modems
This problem is already evident to some degree with VoIP being used by some relevant B2B providers and transit carriers (BT IPX), and the BSkyB/TalkTalk VoIP “PSTN emulation” being used by consumers.
This problem may also extend to other security applications and will need service re-engineering and/or complete service/CPE replacement to rectify
VoBB will also not have the “line powering” capability of the PSTN – telecare and other non-voice services will need alternative power arrangements.
Most obvious are that those that require “baseband” connectivity such as Redcare and related security applications that will cease to work

6. OFCOM’s work programme - scope
We recognised the challenges that PSTN evolution could involve in our 2016 Connected Nations report (section 7.18 onwards)
The responsibility to ensure that migration does not result in disruption to end users lies with industry
Ofcom will monitor progress, recognising there will be a need for coordination
PSTN switch off requires a complicated dialogue, involving a wide range of parties - Ofcom has formed a cross industry working group with CPs and OTT service providers

7. Ofcom’s work programme - outputs
Ofcom aims to set out PSTN migration implications shortly, possibly as part of the Connected Nations Report 2017
This will require input from all parties:
CPs need to provide realistic migration timetables
Service providers need to better understand how existing services may fare in the new environment, so as to focus activities on service assurance during transition, including testing plans and schedules
NICC “All IP” technical standards sub group is a vehicle for the technical and testing work
Ofcom is emphasising to CPs contemplating PSTN switch off that they have a number of responsibilities to both consumer and broader stakeholder groups, particularly with regard to service compatibility issues
Need to ensure that suppliers and OTT service providers have access to telecommunications test environment(s) that are representative of the eventual deployments and that a clear explanation and evaluation of the system or service failure scenarios that could result can be derived
CPs will have to provide good quality information on the schedule of transition to ALL-IP and endeavour to work with service providers to minimise threats of disruption
They will also be asked to determine if customers have services/equipment that may pose compatibility issues before migration and commit to explaining the potential impact and resolving problems as they arise

8. PSTN/VBD based services really need replacement with connectivity solutions with a long term future
Longer term solution is to move to a “data centric” or “all IP” approach
Existing consumer “wireline” broadband may have some drawbacks – these services may not be available in all premises and don’t always provide high levels of resilience - typically local mains power failure will cause loss of service unless supported by UPS or battery back-up
Generally, existing broadband connections may be supporting multiple services – in order to ensure any “safety of life” service works effectively, some level of prioritisation for the relevant data traffic may be necessary
Security will also be a concern – if something is connected to the Internet, someone will try to hack it.

9. What does the right service solution look like?
Industry needs to define desired attributes to meet applications needs - coverage aspirations (say ~100% of domestic premises), resilience (say 1 hour battery power to cover mains failure), data throughput required, preferred network protocols etc – and then look to procure
Non – internet IP connections may be a preferable option – smart meters use separate wide area wireless connections to provide broadly equivalent connectivity with better coverage, security and resilience
View the need as a classic Internet of Things application for which a range of solutions are developing