Your employer - a legal company - is working on a large case,
involving several different regional offices. The client's chief
counsel has sprung a surprise visit on you, and she's arriving from
New York tomorrow. Your legal team has to collect all of the
outstanding case data from several parts of the company, and there
are reams of documents to process - but the broadband network is
down. Your CEO just kicked you out the boardroom, and now you're
kicking yourself for not
building appropriate reduncancy into your network. How could
this have been avoided?
With companies dependent on the Internet for intra-and
inter-company communications, the
threat of network downtime is
more unacceptable. But measures are available to large and
small companies to prevent the worst.
"It starts with establishing a
service level agreement with your main service provider," says
Ted Bissell, managing consultant at the PA Consulting Group. "You
should discuss about
what kinds of outages to expect." If your SLA says your network
will be up in 30 minutes after a failure, that might be
theoretically acceptable.
"When suppliers are a problem, you agree an escalation path. You
define a
series of
outage levels, and in the most severe category you end up with
a quick level of escalation to senior management," Bissell
continues. That sounds fair, but if our legal company's network
stays down all night, no amount of escalation the following morning
will get back the business they'll lose.
To really avoid the problem, two broadband links from different
service providers might be necessary - but beware: "If you take two
service providers, they might both rent the same access from BT and
end up in the same fibre duct," says Margaret Hopkins, principal
analyst at telecommunications market watcher
Analysys
Mason. "So you'd have to talk to your service providers to
ensure your links are in different ducts."
To be truly redundant, connect to different broadband providers
from different sides of the building, says Bissell. "Service
provider A comes in through one part of the building, and service
provider B comes through the waste facility. If a road digger goes
through provider A's line, provider B can happily continue
providing data service." That solves the problem of an immediate
physical rupture, but doesn't avoid problems at the exchange. If
something happens to an exchange and both broadband connections are
housed there, your business users will soon realise how
inadequate your broadband continuity plan is. So, the savvy IT
department will ensure that the different broadband links are
connected to different points of presence. But the further you get
from large cities, the harder this could be, Hopkins warns.
Companies too far out may only have one point of presence to choose
from.
George Yun,
principal at
Interactive Broadband Consulting Group, reminds
network planners to consider the fail-over process between
links. If one link fails, does the network understand how to
automatically bring the other one up and keep it running, and how
long will the switchover take? Several companies provide dual-link
routers that can help with the fail-over process. There is also the
added benefit of aggregation. When both links are up and running,
the local area network (LAN) sees them as a single, higher-speed
wide area network (WAN) link.
Yun also says a wireless connection can help as a back-up for a
data network. "Back-up satellite links might be ideal. They're
often slow, with high latency, he admits. "They're also expensive.
But the problem with
alternative fixed wireless solutions like Wimax is that you
don't have ubiquitous coverage." In the UK there's little WiMax at
all. Microwave links can also be used for high speed line of sight
connectivity, backing up faster links between buildings in a
metropolitan area network.
Will firms with several branch offices want to invest in a
redundant high-speed link for each of them? Such decisions require
a cost-benefit analysis, says Yun. One possibility is to equip
offices with cheap alternative links (maybe even a dial-up modem)
as back-up, providing some connectivity in an emergency. The other
option is to build efficiency into the wide area network at the
start, using caching systems that store certain data locally for
access during a network failure.
Satellite, microwave and highly-redundant landline links from
different parts of the building might be an option for enterprises
and diligent mid-sized companies, but not for many smaller firms.
Hopkins says that many
small office
and home office (Soho) users or very small businesses could get
away with a 3G link, such as the dongle offered by network operator
3 for laptop connections with a flat rate fee. Whichever route a
company chooses, backup is becoming increasingly important. Now
most senior executives are used to always-on connectivity, an extra
monthly investment will leave you safe, not sorry.