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28 E L EC TR I C AL CONNEC T I ON
AU T UMN 20 1 6
of the International Organisation for
Standardisation and the International
Electrotechnical Commission (ISO/
IEC JTC 1) share similar missions of
developing, maintaining, and promoting
standards related to information and
communications technology. However,
while TIA standards represent the
consensus positions of their North
American corporate constituents, ISO/IEC
JTC1 standards represent the consensus
positions of their member countries.
As a result, voting within these
organisations is also different, with
TIA recognising one vote per member
company and ISO/IEC recognising one
vote per member country. A voting
practice that accommodates regional
preferences is the key reason why there
are additional shielded options, such
as Cat 7A/Class FA specified in ISO/IEC
standards compared to TIA standards.
(See Table 2.)
While specifications for same-
bandwidth balanced twisted-pair copper
cabling systems are well harmonised
between TIA and ISO/IEC, there are a
few differences that stand out-most
notably the naming convention for these
cabling systems. In ISO/IEC standards,
structured cabling components (e.g.
cables, connecting hardware, and
patch cords) are characterised by a
performance “category” and are mated to
form a permanent link or channel
that is described by a performance
“class.” In TIA standards, components and
cabling are both characterised by
a performance “category.” ISO/IEC
and TIA equivalent grades of cabling,
arranged in order of increasingly more
stringent transmission performance, are
shown in the table.
Note that, although ISO/IEC Class
I and TIA Cat 8 cabling systems are
specified to 2,000MHz, they will not be
electrical supersets (i.e. exhibit superior
performance) of ISO/IEC Class FA cabling
up to 1,000MHz.
Both the ISO/IEC JTC1 and TIA TR-42 are
developing requirements for the balanced
twisted-pair media that will support the
25GBase-T and 40GBase-T applications
that are currently under development
by IEEE 802.3. ISO/IEC is developing
requirements for Class I cabling
constructed from Cat 8.1 components,
and Class II cabling constructed from
Cat 8.2 components. TIA is developing
requirements for Cat 8 cabling
constructed from Cat 8 components and
is also undertaking an initiative to develop
Class II cabling requirements that will
harmonise with ISO/IEC. Class I and Cat
8 cabling specifications support modular
RJ45-style connectors. The performance
associated with Class II cabling can only
be realised when Cat 8.2 cables are used
in conjunction with non-RJ45 interfaces
such as the Siemon TERA connector.
Draft ISO/IEC Class I and II, and TIA Cat
8 cabling specifications, are mature and
currently circulating for industry comment
and review.
Note that Class I, Class II, and Cat
8 cabling is characterised to 2GHz
and intended to support 30m cabling
channels that contain no more than two
connectors. These channels and the
emerging 25/40GBase-T applications that
they support are specifically targeted for
deployment at the data centre “edge,”
where server-to-switch connections are
made. Data centre designers who can
arrange their rack and cabinet layouts
to support maximum 30m channel
connections at these locations today
will be well-positioned to migrate to
25/40GBase-T when the technology
becomes available.
Q: What steps can a customer take
today to design their facilities in such a
way that they are “future-ready” to install
Cat 8 when product becomes available?
Answer provided by Panduit product
development manager Frank Straka:
Cat 8 is a 30m channel, comprising a
24m permanent link and up to 6m of patch
cable. Therefore, when planning data
centres with end-of-row or middle-of-row
topologies, ensure that your jack-to-jack
links are no more than 24m in length and
that you do not need more than 6m of
patch cords in total. What this means for
patching is you could have two, 3m patch
cords, a 1m and a 5m patch cord, or any
combination that adds up to 6m or less.
For top-of-rack topologies, the 3m
reach should be more than sufficient to
cover any direct switch-to-server links,
especially if the data centre had been
using technologies like SFP+ that have a
reach limit of about 5m.
Q: How similar canwe expect Cat 8
products to be compared to jacks and plugs
existing in themarket today?Will products
be field-terminable? Andwith Cat 8 being
a shielded technology, are there any
anticipated concerns for installers?
Answer provided by Frank Straka:
Cat 8 products are anticipated to
be significant upgrades over existing
Cat 6A products due to the four-times
increase in bandwidth. However, these
upgrades will primarily occur internally
to the jack and plug in order to meet that
bandwidth. Externally, they will be about
the same form and fit as prior category
jacks. This makes sense, as they need
to work with the same patch panels,
switches, and other equipment with
which users are familiar today.
Cat 8 will be field-terminable. Now given
that Cat 8 is shielded, field-terminable,
and with a very high bandwidth, expect
there to be at least some improvements
made to how jacks are terminated in the
field to both meet this new bandwidth
and to ensure a good bond with the shield.
For many contractors, the biggest change
will be going into a shielded system
and ensuring that the cable is properly
grounded. If we connector companies do
our job right, grounding the Cat 8 cables
and connectors will be a seamless process
for the installer.
This article originally appeared in
Cabling Installation & Maintenance.
Reproduced with permission.