BY CLAIRE SWEDBERG
FOR DATA CEN TERS THAT S TILL USE COPPER, Category 8 (Cat 8) cabling promises to quadruple speed to 40
gigabits. Cat 8 could operate at a bandwidth frequency of 2 gigahertz. This increased capacity doesn’t mean copper
will replace fiber optics, but it will offer a relatively low-cost, high-speed alternative.
Several standards organizations are still working on the documentation
for the new category. The Institute for Electrical and Electronics Engineers
(IEEE) is defining the operation of 40 gigabits per second (Gbps) for its
802.3bg standard, while the Telecommunications Industry Association
(TIA) is developing its specifications with three documents—two related
to testing in the lab and in the field and the other related to components.
The International Organization for Standardization (ISO) in Europe also is
developing a standard.
By the end of 2016, the IEEE and TIA should release all documentation,
said Mark Dearing, senior product manager for copper at Leviton Network
Solutions, Seattle, and a TIA committee member.
The TIA-568-C. 2-1, Balanced Twisted-Pair Telecommunications Cabling
and Components Standard, Addendum 1, was remanded to the committee
to address comments at the association’s April meeting. The standard’s
publication could follow shortly or may take a few more months, according
to Stephanie Montgomery, TIA vice president of technology and standards.
Anatomy of Cat 8
Cat 8 cable is composed of four shielded-copper twisted pairs no larger
in diameter than its Cat 6a and 7 predecessors. It uses RJ- 45 connectors,
and it can support 40 Gbps lengths up to 30 meters.
The energy going through the cable will amount to 2 gigahertz (GHz).
Cat 8 will also support lower data rate versions, including 10 GHz for a
distance of 100 meters.
The cable will need more shielding as a result of the additional en-
ergy—in fact, it will need two shielding layers: an inner layer of foil
sheath for each twisted pair and an outer foil sheath for the entire cable.
It’s designed as a short patchcord at the end of a series of cabinets
Therefore, Cat 8 suits high-speed applications between 7 and
or a single cabinet, but it’s not intended to provide cable for the entire
infrastructure. Cat 8 offers a cheaper high-speed alternative to fiber. It
can be longer than a twin axial cable that has a shorter distance limita-
tion (at about 7 meters) than the new Category 8.
“This is really meant for the edge,” Dearing said.
Cat 8 is designed to run at both 25 and 40 Gbps, which fills a gap in
the industry. Through fiber cable, the industry learned there was a need
for the midlevel bandwidth. Fiber transitioned from 10–40 Gbps, and the
jump was too big for the market’s needs at the time.
Cat 8 comes to market
It will be 2017 before the manufacturers can have the products in place
with the proper lab and field testing.
The number of projects that will specify Cat 8 right away is still un-
known. The growth may start slowly.
“I don’t anticipate anyone ripping out their 10G or 40G fiber to re-
place it,” Dearing said. “But, if they need more than 10G, they’ll look at
This could be 40-Gbps fiber or the less expensive Cat 8 in copper.
“This is meant to be an alternative to fiber and twin axial,” he said.
“Category 8 is specifically designed for the data center. You won’t be
using it for anything but a data center.”
While RJ- 45 (already used for Cat 3 through Cat 7a) is the connector
for Cat 8 cable at this point, the ISO is also considering Class 2, a version
of Cat 8 that would not use RJ- 45 connectors but instead would use three
or four other plugs that are common in Europe.
“TIA has chosen not to adopt Class 2 [at this time],” Dearing said. “So,
it remains to be seen how much Class 2 gets adopted.”
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