Business Continuity
How to improve business continuity in
the remote office
Out-of-band tools can ensure
networked devices are always accessible,
even when connectivity is lost.
by Ben Grimes
Businesses today rely on 24/7 system
availability, and while remote system
availability is just one of the many factors
contributing to business continuity, it is
critical. Network outages and related
disruptions in services account for
significant losses in both productivity and
revenue. Traditionally, organizations have
built redundant infrastructures at remote
sites to ensure the stability of the
network. Companies today, however, are
considering whether they can justify the
cost of complete infrastructure redundancy
across multiple sites for the sake of
improved business continuity.
Driven by the advent of IP-based remote
management technologies, businesses with
remote data centers and offices increasingly
are turning to cost-efficient centralized IT
management solutions. These solutions are
not without associated risks. IP-based
access solutions (also called “in-band”
solutions) are dependent on the Internet for
remote access to the infrastructure. An
alternative path, or “out-of-band” access,
to devices within the IT infrastructure is
necessary if Internet access becomes
unavailable for any reason. As IT
administrators consider remote access
solutions, a comprehensive suite of tools
that leverage out-of-band technology to
enable access to business critical hardware
should be considered, even in the absence of
network connectivity.
Traditionally, remote offices have
improved the resiliency of their networks
through hardware redundancy and in-band
management solutions. One way to protect
against hardware failure is to locate
backups for critical hardware on-site. For
certain classes of hardware, most notably
hard drives, this strategy works well. Hard
drives are inexpensive, and mature standards
such as RAID automate backup drive
maintenance and failover.
For more complex or more expensive
classes of hardware, redundancy may be
impractical. In the absence of RAID
controllers or their equivalent, maintaining
mirrored hardware configurations requires
administrators to configure multiple devices
with identical settings, patches and
add-ons. This overhead is difficult to
justify in remote locations that are short
on IT staff.
IT administrators typically monitor the
remote infrastructure using IP-based
management solutions. This software assumes
various forms, including virtual terminal
servers, telnet sessions or browser-based
consoles. The IP-based systems are referred
to as in-band because they require a
properly functioning network (typically an
IP-based network, such as the Internet or a
WAN). If the network connection between the
administrator and a remote device fails, the
application is useless until the network
connection is restored.
From a business continuity standpoint,
in-band management systems pose a
significant problem: They can fail at
exactly the time when they are needed most.
If network access is unavailable due to a
service outage, router malfunction or other
disruption in service, in-band access will
not work. To address this, technology
providers have created a new class of
out-of-band management tools. Unlike
strictly IP-based in-band solutions,
out-of-band tools provide a secondary path
to the remote site for use when the primary
network is impaired.
Out-of-band technology allows network
administrators to dial into a remote
keyboard-video-mouse or serial switch,
viewing the screens of any non-responsive
devices and diagnosing the problems. With
remote power management in place,
administrators can perform hard restarts of
systems, often restoring full functionality
without ever leaving the central office. If
the problem requires on-site staff, the
central office can dispatch the proper staff
for the issue at hand, based on the remote
diagnosis.
Out-of-band management typically requires
a serial console server at the remote site.
When connected to the remote site’s IT
assets (e.g., routers, switches), the serial
console can be securely accessed via a
dial-up connection over the PSTN. If the ISP
is experiencing a network outage, the remote
location can still be accessed via a dial-in
connection. Secure out-of-band access via
dial-up to a serial console server ensures
that networked devices are always
accessible, even when connectivity is lost.
Ben Grimes is CTO and senior vice
president of corporate strategy at
Avocent Corp., Huntsville, Ala.
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