It is widely recognised
that the UK PSTN (Public Switched Telephony Network)
infrastructure is one of the most reliable infrastructures
in the world with examples of services being quoted
as having “five 9s availability” i.e.99.999%
availability equating to some 5 minutes downtime
across the whole network over a twelve month period.
Unfortunately, the same cannot be said for the connectivity,
- the telephone circuits, installed by the various "Tier
I Providers" e.g. BT, COLT, C&W, NTL:Telewest
etc – between their respective Local Exchanges,
located on the periphery of the PSTN and end-user customer's
premises: commonly referred to as "The Last Mile".
Why? Because the various Providers simply cannot be
held responsible for the integrity of these circuits.
They invariably run in 5cm diameter pvc ducts and located
only some 15cm beneath the pavement surface where they
are very susceptible to damage caused during incessant
road works and/or heavy vehicles driving over badly
consolidated excavations.
Add to this vulnerability any number of reasons why
it is not always possible to gain access to conventional
offices or other places of work (including severe weather
conditions, fire, police cordons, transport strike
etc.), not to mention the three main risks of a ‘flu
pandemic, terrorist attack and extensive flooding,
such as occurred throughout 2007, and it can be easily
appreciated that it is the "last mile" that
needs very careful thought when considering the implementation
of business continuity plans.
The vulnerability of "The Last Mile" is
again highlighted in the excellent "Good Practice
Guide Telecommunications Resilience" prepared
by the NISCC (National Infrastructure Security Co-Ordination
Centre) in conjunction with the leading Network providers
and the Civil Contingencies Secretariat, first published
in May 2004 and subsequently up-dated in March 2006
in which they state:-
"...
One of the principal areas of concern is the route
congestion between customer premises and local exchange
or Point of Presence (POP). This is of particular concern
in built up or high density areas such as the City
of London and is often a classic example of a single
point of failure. Due to the historical position of
BT as the incumbent telecommunications Provider before
privatization, the "local loop" or last
mile in the majority of cases is a BT asset. Local
Loop Unbundling (LLU) obliges BT to allow other Providers
use of these assets resulting in third party Providers
selling circuits over the same cable routes as BT.
As there is no requirement for either Provider to discuss
the use of these circuits with the other, they may
be unaware that the customer possibly intended the
circuits to be separated. In this way the customer
may be lulled into a false sense of security. True
separation, or separacy, as it is known, in this example
would have been possible by asking one Provider for
two separate circuits. It is worth noting here that
buying two similar circuits from the same Provider
may actually be more economical than buying one circuit
each from two Providers. This in turn, however raises
concern over the dependency on a single provider..."
This
document also incorporates two extremely relevant questionnaires - one
designed to ask an organisation's Provider and
the other to address key issues internally within an
organisation - which will go some way to identifying
the level of preparedness for a telecoms failure.
Putting this into the context of business continuity
planning, the Civil Contingencies Act 2004 requires
Category 1 responders to maintain plans to ensure that
they can continue to exercise their functions in the
event of an emergency, so far as is reasonably practicable.
The business continuity management (BCM) duty in the
Act relates to all the functions of a Category 1 responder,
not just its civil protection functions. Hence the
legislation requires Category 1 responders to maintain
plans to deal with emergencies and put in place arrangements
to warn and inform the public in the event of an emergency.
But it also requires them to make provision for ensuring
that their ordinary functions can be continued to the
extent required.
There are various options available for providing "The
Last Mile" with greater resilience, connectivity-wise.
These range from the provision of "Dual Parenting" (involving
the provision of duplicate circuits from a second local
exchange) to varying degrees of "Diverse Routing" (again,
involving the provisioning of duplicate circuits but
this time being delivered from the same exchange).
However, all of these options carry a significant additional
cost and the availability of these additional services
may vary from Provider to Provider. Care should also
be taken to ensure that when considering the adoption
of the Diverse Routing option that the Provider is
able to guarantee that the duplicate circuit(s) will
follow a completely separate route from the local exchange
to the customer premises from that of the original
circuit to ensure that the necessary additional resilience
is actually provided.
However, in order to provide a truly resilient solution
for protection against a failure of "The Last
Mile"; - which should include, not only
protection against cut/failed circuits running between
the local exchange and the organisation's premises,
but also a failed premises based PBX or, more importantly,
the inability of some, or all, of an organisation's
employees to gain access to their normal place of work
for any number of reasons; it is necessary to
look beyond the concept of simply providing additional
resilience to the telephone circuit connectivity. This
was clearly in evidence during the floods of 2007 when
it was simply impossible to access Humberside Police
HQ in Hull and in Carlisle in 2005 when the main Carlisle
City Council offices, local police station and fire
station were all rendered inaccessible as a result
of rising flood water forcing the Council to relocate
some of their key personnel to their recovery site
located on higher ground. Unfortunately, in both of
these instances, no provision had been made to recover,
by re-routing, their incoming calls to alternative
DDIs in their designated recovery sites.
The instantaneous and seamless recovery of all inbound
calls directed to any organisation's individual
geographical DDI numbers (local numbers starting 01
or 02) is seen as being absolutely key to any organisation; and
particularly relevant to Category 1 stakeholders who
have specific responsibilities under the Civil Contingencies
Act.
The ability to quickly recover, by re-routing, individual
geographic DDI numbers is not something that the Tier
I Providers specialise in providing but there are a
select few specialist telecoms technology companies
who have focused on the delivery of telecoms business
continuity, including one (GemaTech) that can also
provide network based secure voice recording of all
inbound and outbound calls, together with the recording
of all inbound and outbound calls following an invocation.
The provision of voice recording is seen as a great
advantage in the aftermath of any outage when it is
necessary to investigate what actually happened during
and following any outage. These solutions are also
available via In-house providers as well as under existing
local purchasing framework agreements.
What is vitally important however, is the ability of
any telecoms recovery solution to be able to link into,
re-route calls to, and receive calls from, both Satellite
phones; made available to all qualifying Category
1 Stakeholders via a Civil Contingencies Secretariat
initiative; and also Airwave hand sets to ensure
full interoperability between Local Resilience Team
members and related Emergency Services.
Also vitally important is the ability to invoke partial
invocations, to allow for the fact that only some of
an organisation's employees are unable to travel
to work on a specific day. In those circumstances it
should be possible to re-route only those calls to "missing" members
of staff to their homes or alternative places of work
whilst allowing all other inbound calls to all remaining
members of staff through to their normal desk positions.
Alternatively it may be necessary, on occasion, to
invoke a business continuity plan for a certain section
of the building because of some localised problem affecting
a small number of employees. Flexibility is the key.
For more information on GemaTech's products and
applications email us at web@gematech.com: visit our
web site www.gematech.com or call 0800 328 8354
For more information on Telecoms Resilience generally
visit the Government web site www.ukresilience.gov.uk
and specifically
http://www.ukresilience.gov.uk/preparedness/resilient_telecommunications.aspx
GEC/12th August 2008
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