FEATURE
DAC AND AOC
CABLES ARE A
CRITICAL PART
OF EVERY DATA
CENTRE’S TOP-
OF-RACK AND
END-OF-ROW
DEPLOYMENTS.
Experienced data centre
managers understand all too well
that issues with a single cable
can delay the deployment of a
new system by not only days, but weeks
or even months. Direct Attach Cables
(DACs) and Active Optical Cables (AOCs)
are widely deployed to quickly and simply
turn up service in Top-of-Rack (ToR) and
End-of-Row (EoR) environments. Delays
in procuring the correct cable or even
pressure to respond to tight schedules,
offer complexities that can derail data
centre installations.
New data centre service deployments
often pose challenges to data centre
managers for several reasons. For
instance, each Original Equipment
Manufacturer (OEM) device requires
proprietary coding capabilities, locking
users into limited options for scaling
and integrating numerous OEM devices
throughout their network. Historically, OEM
ecosystems have locked network buildouts
into a single supply source, leading
to derailed installations. Innovations in
DAC and AOC cables resolve challenges
regarding interconnectivity, broaden
supplier sourcing options and decrease
the amount of inventory needed to
be held. These benefits remove the
complexities and keep infrastructure
projects on schedule.
Interoperability is key
Top-of-Rack (ToR) deployments are
credited for simplifying data centre
deployments. Reduced cabling costs
and easy integration of modular rackand-stack
cabinets are key drivers for
the adoption of ToR data centre designs.
ToR directly connects network elements
within a rack to a 1U or 2U switch installed
at the top of the rack. ToR typically uses
lower-cost copper DACs to offer costeffective
in-cabinet cabling in comparison
to designs that run bundles of cables from
one cabinet to the next.
Direct connecting switches, servers and
other appliances pose the challenge
of interoperability. Interoperability in
a ToR environment refers directly to
the compatibility of DACs connecting
devices from different OEMs. Top-of-Rack
deployments that mix switches, servers,
load balancers, or storage appliances
from multiple OEMs must address the
challenge of interoperability.
Many OEM switches and servers
require proprietary cables to ensure
compatibility. When plugging an OEM (for
illustrative purposes this will be called
OEM ‘C’) DAC into a switch, the user
expects a plug-and-play experience, so
the switch will recognise the cable and
not present any alarms. No additional
work around commands or special action
should be taken.
However, if the user was to take the
other end of the cable and plug it into
a server from OEM ‘H’, the server may
not recognise the cable or may present
messages or errors which will alert
network monitoring tools. Dominant
OEM network equipment vendors are
in the business to sell their exclusive
ecosystem. They do not offer a solution
to ensure interoperability across multiple
OEM hardware elements in a direct
connect scenario.
Luckily, third-party solutions are available
to solve this interoperability challenge.
DACs and AOCs can be programmed
in the factory for compatibility to each
OEM. Furthermore, each end can be
programmed for a different OEM.
The hybrid or multi-code DAC solution
offers assurance that multi-vendor
connections are plug-and-play.
Even 40G/100G breakout connections
for multiple OEMs can be supported by
hybrid cables coded for multiple OEMs.
www.intelligentdatacentres.com
Issue 19
45