Cabling: 10G on tap
10 Gbps over fibre has been around for a long time in the
backbone. Now, as 10 Gigabit Ethernet over copper (10GbE) emerges into the sunshine,
it is proving to be a viable alternative to expensive fibre optic cable. The
cost differential is on account of the fact that 10G on fibre uses active components
that cost eight times as much as passive ones making fibre too expensive for
large-scale implementations of 10Gbps Ethernet. Thats why a copper solution
was sought. 10GBASE-T is being touted as that solution. By Faiz Askari
the density of devices in enterprise networks and data centres rises, there
is an emerging need for low-cost, 10GbE over twisted-pair cabling. 10GbE copper
cabling system has been verified to comply with the newly-ratified Institute
of Electronics and Electrical Engineers (IEEE) 802.3an 10GBASE-T standard for
10GbE transmissions over a copper cabling system. The 10GbE over copper system
was the first UTP (unshielded twisted pair) augmented Category 6 cabling system
to fully comply with the IEEE 10GBASE-T standard. A 10GBASE-T standard that
is in the works will support 10GbE over new wiring at distances of up to 330
feet and existing wiring at distances of up to 182 feet.
10GBASE-T doubles the bandwidth
offering a 500 MHz channel (end-to-end) and it can work up
to 330 feet offering fibre-equivalent throughput of 10 Gbps. In comparison,
Cat 6 offers 250 MHz over 10 metres topping out at 1Gbps. The ratification
of the IEEE standard is an important milestone as it removes specification
uncertainties for the manufacturers of 10GBASE-T switches and will lead
to the commercial availability of electronics within the year
10GBASE-T doubles the bandwidth offering a 500 MHz channel (end-to-end)
and it can work up to 330 feet offering fibre-equivalent throughput of 10 Gbps.
In comparison, Cat 6 offers 250 MHz over 10 metres topping out at 1Gbps. The
ratification of the IEEE standard is an important milestone as it removes specification
uncertainties for the manufacturers of 10GBASE-T switches and will lead to the
commercial availability of electronics within the year. For customers, the promise
of near-term 10GbE electronics is critical in their selection of 10G Ethernet
cabling system over lower performance cabling alternatives.
The 10 Gigabit Ethernet Standard is an extension of the basic
IEEE 802.3 standard protocols to a wire speed of 10 Gbps. As an extension, 10G
is still fully Ethernet compatible and retains the key Ethernet architecture,
including the Media Access Control protocol, the Ethernet frame format, and
the minimum and maximum frame size. Just as Gigabit Ethernet followed the standard
Ethernet model, 10G continues the evolution in speed while using virtually the
same architecture thats been used in other Ethernet specifications. 10G
can be deployed with existing network equipment retaining the existing principles
of network operation and management.
There are specific casesfor e.g. data centres, SANwhere
there are genuine requirements for such transmission rates. As of now, though,
penetration is low. Rajesh R Shenoy, Business Head, Building Network Group,
Belden explains, Today customers are waiting for a switch manufacturer
to come out with a robust 10Gbase-T switch. People are waiting to hear from
switch vendors. Cisco and Foundry seem to be ready for a launch in the coming
months. With this the market may move forward. This segment has good prospects
in the near future.
Gaurav Sharma, Senior Consultant, WAN specialist, Network Solutions comments,
10GbE over coppers popularity is definitely picking up in India.
A lot of interest has been generated for this in the last year or so. As modern
day applications are bandwidth-hungry and require lower latency, enterprises
and financial institutions including banks are evaluating 10GbE as a solution
for their data centres or Storage Area Networks (SANs) as it merges with the
existing Ethernet infrastructures.
Although, at this point of time, 10Gbps over copper has found few takers in
India, once support over active devices, especially switches, becomes available,
the technology should take off.
Eliminating external noise
10GBASE-T solves an important issue with Cat6. As transmission
rates climb and signals extend into higher frequencies, other noise sources
come into play; external noise source and alien crosstalk (ANEXT) thats
caused by signal coupling between adjacent cabling channels. Although the magnitude
of alien crosstalk is usually less than crosstalk (NEXT) within the cable, its
effect on channel capacity is greater because it is more difficult to suppress
ANEXT through digital signal processing techniques commonly used in todays
Says Milind Tamhane, Vice-president, Manufacturing, D-Link India: These
are more robust cables, predominantly shielded varieties though there are solutions
with UTP, that are popular in India. More systematic cable dressings to avoid
alien crosstalk, superior jacks and plugs are required.
|Demand for bandwidth has shot up as a result of the
way businesses are using networking to improve productivity. The development
of enhanced client-server applications, and convergence of voice, data,
and video have also fuelled this demand. Sharma of NetSol explains, The
high demand for bandwidth has resulted in an increased demand for higher
speed switches and routers. To help fill this gap, the IEEE has formed a
task force to develop a standard for 10GbE over structured copper cabling.
Tamhane of D-Link points out, Issues like a 10-fold speed boost in
connectivity and the convenience of using copper, are key drivers for this
technology in the Indian market.
Bandwidth-hungry applications, proliferation of
data centres, switches with the 10G capabilities and faster speed and
higher uptime are all factors that are expected to boost the adoption
Higher bandwidth and future proofing
LAN backbones are expected to adopt this technology at the earliest. 10GbE will
encompass all IP networks across the enterprise. It is the preferred LAN backbone
connectivity option today. With 100 Mbps Ethernet to each desktop and 10GbE
connecting the wiring closet switches to the backbone, 10 GbE provides a scalable
interconnection between the LAN backbone switches. Most enterprises are already
migrating to 10GbE on the desktop. It is the preferred interconnect for most
enterprises and is expected to be deployed for applications such as video streaming
to the desktop, aggregations between server farm and service provider data centres,
data centre communication from LAN switches to storage networks, and grid computing.
It is consequently being adopted in desktop and server farms, on campuses.
Dabinder Singh, Head, IT, Greenply Industries says, 10GbE copper technology
is perfect for load balancing and we are also evaluating the technology for
last mile connectivity at selected locations. The technology is helpful where
zero delay is required for resource-intensive applications such as ERP, CRM
Daya Prakash, Senior Manager, IT, LG CNS Global adds, 10GbE over copper
will help speed up throughput and in case the Internet Service Provider uses
this technology it will help provide optimum reliability to users. This technology
can be a boon for mission-critical applications such as ERP and for messaging
and collaboration. It is also beneficial for video streaming.
In the Indian scenario, 10GbE is
already being used within buildings for LAN uplinks. For example, 10GbE
uplinks from the switches to the core are expected to happen in six to
eight months. In the case of inter-switch links, situations where two
large Ethernet switches have to communicate, 10GbE is a must
In the Indian scenario, 10GbE is already being used within buildings for LAN
uplinks. For example, 10GbE uplinks from the switches to the core are expected
to happen in six to eight months. In the case of inter-switch links, situations
where two large Ethernet switches have to communicate, 10GbE is a must. On the
server side NICs will be 10GbE. In green-field set-ups large businesses will
consider 10GbE on copper to future-proof their network because it
is difficult to replace cabling inside walls and in ducts under floors. The
rationale behind this is that cabling will last for at least eight to 10 years
and will support four to five generations of equipment during that time.
10GbE over copper is expected to bring in change in IP SANs that will move towards
10GbE as it offers a simplified and cost-effective interconnect mechanism when
compared to other technologies that are available. Cabling vendors are of the
opinion that the adoption of 10GbE over copper will make high-speed IP SANs
a viable option.
An alternative to fibre?
In terms of capability and uniqueness, in the 10Gbps network, transmission protocols
like 1000Base-T need only 65 MHz of the available 200 MHz (in Cat6). This makes
a Cat6 cabling solution quite stable at 1 Gbps. On the contrary the 10GBase-T
will need the full 500MHz of a Cat6a-augmented solution. This means that a bad
Cat 6a solution will fail faster. It also makes it riskier for customers who
are going in for a Cat 6a solution, that does not provide greater headroom.
With regard to 10 GbE networks being considered a substitute for optic fibre,
Shenoy states, I disagree from the standpoint that says that fibre will
be replaced by 10 GbE in the near future. I think both fibre and copper will
co-exist. They have different uses and capabilities.
Tamhane has a similar view, 10GbE transmission includes all types of fibres
10GBase SR addresses multimode fibre at short wavelength (850nm), 10GBase LR
is using both multimode as well as single mode at 1310 nm wavelength and 10GBase
ER is the extended range of beyond 40 km using single mode fibre at 1550 nm.
As to whether 10GBASE-T will be an alternative to fibre optics, the answer is
a clear no, because both the media have their specific applications.
The environment where one expects reasonable low electronic noise, shorter distances,
less MAC (moves, adds & changes) and cheaper solutions may move to 10 GbE.
Copper vs FTTD
As to whether 10GBASE-T will be
an alternative to fibre optics, the answer is a clear no,
because both the media have their specific applications. The environment
where one expects reasonable low electronic noise, shorter distances,
less MAC (moves, adds & changes) and cheaper solutions may move to
The idea of fibre to the desktop (FTTD) has been around for quite some time.
Early proponents of FTTD cited problems with UTP systems and limited distances
as reasons for their recommendations. There are 10GBASE-X fibre applications,
and in fact, those needing 10G bandwidth have had fibre options for some time
now. In evaluating copper versus FTTD, it is important to include overall network
costs (including electronics), not just cabling costs.
Fibre components for 10G are expected
to settle at a cost that is roughly 10x the cost of
a gigabit port. On the copper side, however, the cost
will be about 3x the cost of a gigabit port or roughly
one third the cost of a 10G fibre port. All PCs shipping
today come with 10/100/1000 Mbps copper network interfaces.
In order to use FTTD, that investment will go to waste
and a new fibre card will need to be procured. The same
cost differential applies. It is also noteworthy that
the 10GBASE-T copper chips will auto-negotiate from
10 Mbps up to 10 Gbps. This means that one chip will
be used for all network connections. It is far less
expensive to mass produce one chip than several varieties.
As 10GBASE-T chips begin mass production, they will
begin to surface in server NICs, switch ports etc.
In any growing market, identifying initial challenges and how to deal with them
is a decisive factor in a technologys future. 10GbE networks are gaining
ground but some challenges remain to be tackled.
Highlighting key elements that need to be worked upon, Shenoy says, Customer
awareness is low as to what a real 10GbE solution is. Customers take a call
on the basis of market perception rather than the technical reality. This could
hamper adoption of this technology in the long run. 10GbE vendors should show
the path by telling the customer what the pros and cons of going for a Cat6a
solution are as the technology hasnt been ratified yet.
Sharma states, The future of 10GbE market is definitely bright in India.
To quote the data from a survey done in India, it was quite evident that nearly
50 percent of organisations understood the importance of upgrading their networks
and considered future-proofing their backbone cabling infrastructure using the
latest 10G Ethernet equipment.