Cabling Special: Cabling Technologies

Get wired for the future

Akhtar Pasha takes a peek at the latest cabling technologies that are expected to hit the market in the near future

When deciding on an IT deployment, it is usually the hardware and software that attract the most attention. Yet, the successful performance of a network relies heavily on an element that often takes a back-seat—the cabling infrastructure.

Making a choice about the right cabling systems is a key decision. When a company’s cabling system is inadequate for the amount of traffic running over it, the network slows to a crawl and may crash. As Venkatesh Babu K S, technical manager, India & SAARC, Systimax Solutions puts it, “Cabling is just five percent of the total investment in IT infrastructure. But [the remaining] 95 percent is at stake as it [poor cabling solution which cannot meet a company’s future requirements] can send the network crashing.”

Deciding which cabling infrastructure systems to invest in depends on the performance level you need from the network which in turn is based upon the applications to be run now and in the future. Advanced business applications such as voice over IP, IP-based videoconferencing, IP-based security and IP-based storage (IP-SAN) are taxing networks and are pushing cabling infrastructure to the brink.

Customers choosing to install older technology such as Category 5 or 5e will lose out on the extended life cycle of their investments. You can either pay more for Cat 6 or pay less today for Cat 5 or 5e and face the cost of reinstallation tomorrow.

In India, the structured cabling market predominantly comprises Unshielded Twisted Pair (UTP) cables and all new installations after October 2003 are on Cat 6. It becomes necessary to understand the reasons driving this trend.

Which ‘Cat’ has more lives—Cat 5e vs. Cat 6?

Venkatesh Babu K S says that cabling infrastructure is just five percent of the total IT infrastructure investment. But the remaining 95 percent is at stake as that 5 percent can send the network crashing

The Cat 5 standard has been supplanted by Cat 5e. The most popular horizontal cabling systems today are Cat 5e or Cat 6 UTP. Both these systems are capable of carrying data at Gigabit speeds. The biggest selling point for Cat 6 is its ability to transmit data at 250 MHz—two and half times the frequency of Cat 5e over a distance of 10 metres.

Rajesh Shenoy, key account manager-India, Belden CDT (Networking Division) says, “Cat 5e is 24 AWG (American Wire Gauge), while Cat 6 is a 23 AWG, which is thicker in diameter and reduces the loss of electrical signals. This when combined with the twist in the lay-length of the cables (twist of the cable) controls the cross talk.”

Vikas Pinjarkar, general manager-Sales (SCS), D-Link India says, “This (Cat 6) technology includes better insertion loss, near end crosstalk (NEXT), return loss and equal level far end crosstalk (ELFEXT). These improvements provide a greater signal-to-noise ratio, allowing higher reliability for current applications and higher data rates for future applications.”

Because of its improved transmission performance and superior immunity to external noise, systems operating over Category 6 cabling will have fewer errors vis-à-vis Category 5e for current applications. This means fewer retransmissions of lost or corrupted data packets under certain conditions, which translates into higher reliability for Category 6 networks compared to Category 5e networks.

Enterprises deploying Cat 6 solutions and structured cabling vendors agree that there is no application today that calls for investment in Cat 6. Dileep Kumar R, technical & product manager, PremisNEt, Krone Communications, says, “Though there is no application available today that demands Cat 6, customers are investing in it for ‘future-proofing’.” It is difficult to replace cabling inside walls and in ducts under floors. The rationale behind this is that cabling will last at least 10 years and will support at least four to five generations of equipment during that time. If an application in the future requires equipment running at much higher data rates which in turn requires better cabling, it will be very expensive to pull out Cat 5e cabling and replace it with Cat 6.

Hughes Software Systems’ new facility in Bangalore has deployed Belden CDT Cat 6 cables for the horizontal systems. Its (Hughes) senior project manager-IT Charles Padmakumar states the reasons for HSS’ Cat 6 investment. According to him, cabling infrastructure is similar to the electrical wiring of a house. You would not like to take chances with your expensive electrical appliances by using them with poor wiring. The same holds true here. “Typically when we looked at Cat 6 deployment we were looking for capital investment protection for at least 10 years. The investment in Cat 6 is justified if you own the facility or even if you have taken a lease with a tenure of 10 years. The third aspect that makes Cat 6 a better option is the price performance of Cat 6 over Cat 5e. Cat 6 comes at a premium of 20 to 25 percent but it gives you investment protection for the next 10 years,” adds Padmakumar. However, companies renting a place for three to four years will find Cat 5e to be a more cost-effective proposition.

What’s next

Cat7 is the answer that comes to mind. But wait. Did we hear someone talking about 10-Gigabit Ethernet (10GBASE-T) over copper UTP? Trade analysts and vendors say that 10GBASE-T (10GbE over copper UTP) in the backbone and horizontal cabling systems is going to be the next big thing. This technology is called augmented Cat 6. Although it is not ratified by TIA/TIE, augmented Cat 6 is supported by IEEE 802.3 a (10GBase-T) for UTP.

What 10GBASE-T does is that it doubles the bandwidth offering a 500 MHz ‘channel’ (end to end) and it can work up to 100 meters offering a throughput of 10 Gbps, which is equivalent to fibre. In comparison, Cat 6 offers 250 MHz over ten metres topping out at 1Gbps. K K Shetty, country manager, AMP NETCONNECT, Tyco Electronics Corporation India says, “100 Mbps is already available at desktop and if an enterprise has, say, 100 users they can use 10G at the backbone to support their network infrastructure. We have customers who have pushed 10G at the backbone so that they can offer 1G at the desktop. In comparison, 10G on fibre using active components is eight times costlier. This amount can be saved using 10GBASE-T. 10GBASET over 55 meters is something that we already have and customers are showing interest in it.” Fibre solutions are proving to be too expensive for large-scale implementations of 10Gbps Ethernet, so a copper solution is being sought.

Additionally 10GBASE-T solves an important issue seen in Cat 6 cables. As transmission rates climb and the signals extend into higher frequencies, other noise sources come into play such as external noise source, alien crosstalk (ANEXT). It is caused by signal coupling between cabling channels adjacent to one another. 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 today’s equipment.

Who would deploy augmented Cat 6?

Just about any organisation running a data centre will need to consider 10GBASE-T in the next 5 to 10 years. Just take a look at the current take-up of 1000BASE-T (Cat 5e) and then consider what was said about it only two or three years ago. Vendors say that 10GBASE-T will be deployed in enterprise data centres, in clinical trials, IP-SANs, telemedicine and for distance learning. Offering a contrasting viewpoint, Deepak Jagtiani, national sales

manager, Molex (India) says, “10GBASE-T is no more than a marketing promo as they [vendors cheering 10GBASE-T] have nothing to lose and everything to gain. There is no-clear means or method to measure alien crosstalk which 10GBASE-T handles. Additionally the standard is not ratified by TIA/TIE.”

Anyone for Cat7

Though there is no application available today that demands Cat 6, customers are investing in it for 'future-proofing', says Dileep Kumar R

Cat7 provides a 600 MHz channel and offers 10G on STP (Shielded Twisted Pair) that essentially fixes alien crosstalk. Cat7 utilises PiMF (Pairs in Metal Foil) cables where each individual pair is wrapped with a foil shield along with an overall shield braid around all four pairs. The individually shielded pairs virtually eliminate crosstalk between pairs in the same cable. The downside is that individual shielding of cables makes Cat 7 cabling bulky, heavier and increases the overall circumference. If you have not provisioned for laying Cat7, you will need a larger groove to accommodate it. Shetty says, “Cat7 can be ideal in an industrial environment where electrical interference is high.” Tyco has recently bagged a contact for its Cat7 cable from a PSU.

Fibre for backbones

Optical multimode 3 (OM3) fibre supports extended gigabit driving distances to 550 meters, pushing the evolution and extension of enterprise networks. Kumar of Krone Communication says, “OM3 is a 10G standard that allows data transmission over a distance of 300 meters and beyond at 850 nm (nanometres).” Since 80 percent of mission-critical data travels over the backbone, network architects should develop vertical networks capable of supporting terabits, petabits and beyond.

OM3 fibre is essentially a multimode fibre that can utilise lower-cost light sources, such as light-emitting diodes or vertical cavity surface-emitting lasers (VCSEL), to achieve speeds and distances previously possible only through more expensive single-mode fibre solutions. OM3 fibre is different from other multimode fibres, due to the quality of its glass. In standard multimode fibre, there are small imperfections called index depressions on the axis of the glass. These index depressions alter the refractive index and parabolic profile across the diameter of the fibre. With advances in fibre technology, these imperfections had no effect because LED systems use the whole parabolic profile across the full diameter of the glass. OM3 fibre is being made flexible enough to support fibre-to-the-desk applications. With MT-RJ and VF-45 small form factor (SFF) connector technology, terminating fibre is faster and easy.

Whatever new technologies one may decide upon, today’s structured cabling decisions will determine tomorrow’s business capabilities.

akhtar@expresscomputeronline.com