NETWORK RESILIENCE
Understanding the difference between
By Steve Cummins, VP,
Opengear
resilience and redundancy to ensure
www.opengear.com
uptime and business continuity
The distinction between network resilience and network
redundancy may remain puzzling for many businesses,
but the importance of understanding such differences is
absolutely essential. While a resilient network may contain
some redundancy, a redundant system isn’t always resilient
to a competent standard.
Redundancy is a process through which alternate or
additional instances of network devices, utilities and
equipment are installed within the network infrastructure
and other elements such as backup generators, or alternate
cooling circuits are brought in to support the smooth
operation of the network.
Typically, a redundant network duplicates critical elements
and devices that keep the network running, so that if one
path fails, another can be used. That’s fine as far as it goes,
but it doesn’t solve the problem of business continuity –
far from it. After all, if there’s a primary network failure or
something goes wrong with any piece of equipment other
than the redundant elements, the network remains down.
Just adding switches or routers won’t resolve this issue.
If an engineer cuts through a cable, the network may go
down no matter how much duplicate equipment is in place.
Redundancy can often be expensive too. Unsurprisingly,
organisations often baulk at spending large sums on data
connections that will be idle most of the time.
Maximising uptime with resilience
If a business is serious about maximising network uptime,
it has to go beyond redundant equipment. That’s where
end to end resilience is so important. Resilience is all about
recovering quickly to ensure that the company is operating
normally soon after a network outage. Part of this is knowing
there’s a problem in the first place. Many organisations today
face issues in being able to quickly identify and remediate
reliability or resilience issues. Again, redundancy on its own
won’t deliver this awareness, but resilience can.
Take a large organisation with a Network Operations
Centre. They may have lots of offices around the world with
attendant time zone issues. As a result, they may struggle to
learn that an outage has even occurred because they’re not
proactively notified if something goes offline. Even when they
are aware, it may be difficult to understand which piece of
equipment, at which location, has a problem if no one is on-
site to physically check.
This enables a system reboot to be quickly carried out
remotely. And if that doesn’t work, it might well be that an
issue with a software update that’s the root of the problem.
With the latest smart out-of-band (OOB) management
devices this can be readily addressed because an image of
the core equipment and its configuration can be retained,
and the device quickly rebuilt remotely without the need for
an engineer visit. In the event of an outage, therefore, it’s
possible to deliver network resilience via failover to cellular,
while the original fault is remotely addressed, enabling
business continuity even while the primary network is down.
Building in resilience through the OOB approach is
expensive, but it’s money well spent. You might use this
alternate access path infrequently but when you need it, you
really need it. Moreover, resilience is typically far cheaper than
having to buy in large volumes of redundant equipment, for
example. This is increasingly the case as the deployment of
edge locations increases. An organisation may be able to
afford redundancy at a core data centre, powering multiple
businesses and processes, but that same redundancy can’t
be built into every single data rack or data closet at a small
remote location.
Maintaining continuity
So, network redundancy can help businesses mitigate
the risk of unplanned outages and help ensure business
continuity, but it doesn’t necessarily bring resilience. Simply
implementing redundant equipment will never ensure that
a business can get its full network ecosystem from core to
edge up and running normally again quickly. Ultimately, it’s
having that resilience in place that’s key to businesses. After
all, networks are the fundamental backbone to the success of
organisations today, and many businesses will benefit from
bringing network resilience into the heart of their approach
from the very outset.
Dealing with outages
True network resilience is not just about providing resilience to
a single piece of equipment, whether that be a router or core
switch, for example. In a global economy, it’s important that
any such solution can plug into all of the equipment at any
data centre or edge site, map it and establish what’s online
and offline at any given time.
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