STRUCTURED CABLING: Superior Technology, Lower Prices

The biggest worries for network administrators are downtime and lack of

repeatable, installed performance. Researches have pointed out that more often

than not inferior cabling system is the cause. This is ironical, given the fact

that the structured cabling system investment is about just five percent of the

total network investment and it outlives most of the other networking

components.

Ironical still is the lack of attention for the selection of cables for the

network. The more visible and relatively hi-technology connectivity components

attract most of the mind share. The fact is that cable quality is the bottleneck

in most networks, and given that once installed cables are difficult to replace,

this bottleneck remains for the network’s life. Installing standards-compliant

structured cabling systems can reduce downtime to a large extent. Of course,

what is important here is that networks remain standards-compliant post

installation rather than under test conditions. For example, twisted-pair cable

must provide the user with superior electrical performance both

"on-the-reel" and in use.

The user (read enterprise) needs to view structured cabling as an investment

protection. The first step in deploying a structured cabling solution is to

establish the aims of network implementation. Besides software and hardware,

understanding the networking trends helps. Local area network (LAN) technology

has been around for over 20 years. The first decade of the LAN technology

development was on a department basis. It consisted primarily of Ethernet and

Token Ring products that delivered about 200—500 kbps per user. The entire

network was capped at 10—16 Mbps. But today, the corporate computing

marketplace has been almost completely converted to the LAN-based model, with

over 80 percent of all PCs attached to corporate LANs. The rate at which these

LANs process critical information has multiplied and new higher-speed LAN

technologies like switching, multiple 100 Mbps Ethernet replacements, and ATMs

have come to the forefront.

Technology Options

Cat 6 Must-haves...

Following are the top three areas that required new development work for Category 6 specifications:

n A Single

System: Today’s structured cabling is a single cabling system (copper or

fiber), which covers the whole building for all voice and data (including CCTV

and video) requirements. A structured cabling system consists of outlets, which

provide the user with an RJ45 extension. The outlets are either one or two RJ45

connectors mounted in a standard single gang face plate, or as single snap in

modules which can be fitted into floor boxes, single gang face plates (up to two

modules) or dual gang face plates (up to four modules). The system enables each

user outlet to be cabled back to a hub using an individual cable of four twisted

pairs of copper. The cable can be Unshielded Twisted Pair (UTP) or Shielded

Twisted Pair (STP), or Foiled Twisted Pair (FTP). And the cable is connected to

the back of the user outlet by means of an Insulation Displacement Connection (IDC)

connector. In India, it is generally the UTP.

Parameters: The most important point about structured cabling is that

every vendor has to conform to the parameters specified by the Standards

Committees like TIA/EIA or ISO. These standards tell you the performance

parameters like how a set cabling system should be and comply with and how the

individual components on the system should measure. The parameters involve:

attenuation, pair-to-pair NEXT, PowerSum NEXT, ELFEXT, Powersum ELFEXT, Return

Loss, Delay Skew, pair-to-pair ACR, and PowerSum ACR. Though all the words are

technical jargons, in short they mean the noise levels rating, the resistance

and data loss as a consequence, etc.

Cable Management: While cables have a very consistent geometry

throughout their length, its when the signal transitions from a cable to a

connector that a potential for discontinuity exists. The use of the cable

manager provides better control over the placement of the wire pairs and

automatically resolves the important issue of keeping the unsheathed wire pairs

as short as possible up to the 45-degree IDC terminals.

Impedance Matching: Impedance defines the best "path" for

data to traverse. For instance, if the signal is transmitting at an impedance of

100 Ohms, it is important that the structured cabling also possess an impedance

of 100 Ohms. Any deviation from this set point will result in part of the signal

being reflected back towards the source of data. Impedance variations can occur

for many reasons. One is from the manufacturing process itself. Any deviation of

conductor-to-conductor spacing or insulation properties will cause impedance to

vary. Another way in which impedance can vary is by mismatched components. In

fact the new Category 6 standard has taken this on board and has brought down

the impedance level from + or - 15 percent for Category 5E to +or- 6 percent for

Category 6.

n Technology

on Copper: Today one hears mostly about Category 5 Enhanced (Category 5E),

Category 6, and Category 7 solutions. Not going into much detail to what each

Category of systems indicate, it must be mentioned that Category 6 is a ratified

standard today. Prior to June 2002, it was Category 5E that was a ratified

standard, while Category 6 was a draft standard. The other standard, we hear is

the Category 7 standard, which is still an ISO development, and not yet

considered by TIA. Though innovations in Copper cabling are relatively few,

there are differentiated products like bonded pair cable solutions that promise

significantly higher levels of post installation performance.

Category

6 is a full duplex Ethernet Physical Layer specification for 1000 Mb/s operating

over Category 6 Balanced Twisted Pair Cabling (1000 Base-TX.). This means

additional performance parameters for rejection of noise, increased performance

criteria for common parameters like channel attenuation and return loss, and

extended bandwidth from the Category 5.

The general difference between Category 5E and Category 6 is in the

transmission performance and extension of the available bandwidth from 100 MHz

for Category 5E to 250 MHz for Category 6. This includes better insertion loss,

Near End Cross Talk (NEXT), return loss, and Equal Level Far End Cross Talk (ELFEXT).

These improvements provide a higher signal-to-noise ratio, allowing higher

reliability for current applications and higher data rates for future

applications. Ideally suited to high performance applications such as gigabit

Ethernet, Category 6 has some significant advantages over and above Category 5E

cabling infrastructure. Full characterization to 250 MHz provides for two and a

half times the usable bandwidth of Category 5E systems.

There is already an increased talk about Category 7. This is an ISO

development only, not even considered by TIA. It is proposed ISO 11801 Class F

and addresses bandwidth up to 600 MHz. Category 8/Class G is again proposed ISO

draft.

This is seen as "Broadband Premises Cabling" for 1 to 2 GHz.

However, the proposed channel length would be contained to 50 m. Now that the

Category 6 has so much more and that there are simultaneous developments

happening in fiber too, experts advise not to bother even beyond Category 6.

n Technology

on Fiber: Two general types of fiber have emerged to meet user requirement:

multimode and single mode. Single mode fibers can propagate only the fundamental

mode. Multimode fibers can propagate hundreds of modes. However, the

classification of an optical fiber depends on more than the number of modes that

a fiber can propagate. An optical fiber’s refractive index profile and core

size further distinguish single mode and multimode fibers. The refractive index

profile describes the value of refractive index as a function of radial distance

at any fiber diameter. The standard core sizes for multimode step-index fibers

are 50µm and 100µm. The standard core sizes for multimode graded-index fibers

are 50µm, 62.5µm, 85µm, and 100µm. Standard core sizes for single mode

fibers are between 8µm and 10µm. In most cases, the material used in the

preparation of optical fibers is high-quality glass.

Market Information

n The Big

Three: Avaya, Tyco, and D-Link were the major shareholders in the Indian

structured cabling market. Avaya and Tyco, which account for close to 60 percent

of the market share, are continuing to dominate the market. Avaya had about 40

percent market share, while Tyco has about 21 percent. D-Link’s market share

stood at close to 17 percent.

Systems integrators today see Tyco as number one in south, east, and central

India, while Avaya is considered strong in north and west. Meanwhile D-Link,

Krone, Molex, Panduit, and Finolex too are consolidating their bases. This year,

some more international brands like Belden and Nexans could be making their

presence felt.

n Copper Rules

the Roost: On the technology front, the adoption of latest technology is

gaining momentum. The market is moving from Category 5E to Category 6. Copper is

winning the horizontal battle, primarily because of the cost of components for

100BaseT and backward compatibility to easily support legacy systems. Though

fiber costs will continue to decrease due to economies of scale, the belief is

that there will still be a substantial price premium on fiber components such as

NICs and switches, and potentially much more infrastructure to replace with a

move to fiber. Category 6 standards copper cables promises enhanced performance

of 250 MHz and copper to desktops, which is still cheaper.

n Fiber

Picking Up: The penetration of fiber in the backbone has been about 30

percent, and rising. The attractive proposition for fiber has come from campus

networks. But fiber to the desktops will take several more years. In India, it

has been the 62.5 micron multimode fiber that has been growing. However, of

late, 50 micron multimode is gaining ground. Single-mode is still sparsely

deployed. It is not because the cost of the cable. Though the cable is cheaper

than the multimode, the electronics required to run on the single-mode are

expensive. Only, telecom companies have been deploying single-mode fiber in

their WANs.

n Price Drops:

In India, most of the cables are still imported and the duty rate too is

high. As a result, significant price drops were not a norm until the previous

years. However, tough market conditions last fiscal saw forced erosion in

prices. The pressure came from the unorganized sector, which offered low-priced

cabling solutions sourced from the gray market. Major vendors made about 10—12

percent reduction on the price front.

n Improved

Channels: The focus of vendors has been on training and consolidating

channel partners. Vendors like Molex, D-Link, Krone, Panduit, and Tyco focused

on roadshows and education. Moreover, they not only have added stockists and

increased their presence to other cities, but have also looked at becoming total

solutions providers.

n More

Manufacturing in India: Players like Tyco, Molex, Krone and D-Link are

having their manufacturing plants expanded and are gearing up to provide

products for the global markets. Molex announced that it would be manufacturing

majority of the Category 6 products in India. Tyco too is looking at India as a

big manufacturing base. Europe would be offloading work to India. It would be

manufacturing copper patch chords, fiber optic accessories, and then follow it

up with IOs. India is the No 1 priority for all these global vendors in the APAC

region.

n New Offers: In

line with the standards and even beyond them, players have been launching new

products in copper. For example, Krone launched the TrueNet Category 6 solution

that offers a 100 percent throughput warranty or a zero bit error rate; Molex

will be introducing data patching systems and the patch chords; Tyco introduced

OM3 fiber for gigabit Ethernet and AMPACT system among several other products.

Belden is bringing into India its patented Bonded Pair technology, wherein

conductors in pairs remain attached to each other, ensuring virtually nil impact

of installation stresses. It is also to introduce a product that guarantees

performance up to 600 MHz. Panduit introduced a complete Category 6 solution and

has also launched Panview, an active cable management system.

Buying Tips

n Involvement:

Remember, you get what you spec and inspect, not what you expect! So remain

involved during technical discussions and evaluation. Don’t leave cable

selection to chance or to a party that has vested interests different from your

objectives.

n Technical

Specs: The technical considerations to keep in mind while designing a

network and choosing components and vendors include:

Lower bit error rate

• Higher throughput of a system

• Less network downtime

• Future proofing

• Easier installation - "reduced testing time"

• Easier migration to higher data rates

• More attenuation & NEXT available for other
  
  components

To achieve the best results keep the following tips in mind:

n Committed

Brands: There would be minimal difference between one vendor and the other

for Category 5e systems. But going for branded solutions from those vendors who

are committed to the Indian market really pays off, as cabling is a very

important investment. The point that needs to be kept in mind is to go for the

technology leaders and those organizations, which are part of the international

standards committees. This would ensure that one is not only getting a quality

solution but also future-proofing the investment. Installing a Category 6

compliant network requires much more effort up front to ensure that genuinely

compliant systems are short-listed, and provide installed performance as per the

recently ratified Category 6 standards

n Standards

Compliance: Standard Complaint solutions are a must. This is because these

standards are independent of both technologies and the vendors. And they are

designed to meet future technology adoptions. With convergence coming to the

forefront, and attention moving towards VoIP in the enterprises, wiring shouldn’t

be an afterthought. Enterprise can migrate to VoIP even if they have a legacy

Categories 3—6 cable with upgrade to 100-Mbps switched Ethernet and above.

The approach to take on standards compliance is "Let The

Manufacturer Hide Nothing". Obtain written performance values on Input

Impedance and RL; Attenuation; NEXT (including PowerSum); ACR (including

PowerSum); Delay Skew; FEXT/ELFEXT; CAP Unbalance.

Obtain all the data for physical, electrical and mathematical

equations and make an effort to compare and contrast values along with

conducting some actual testing. Some manufacturers publish their products’

best performance as their spec, while the best manufacturers publish their

products’ worst performance as their spec. Stick to the latter category and

you are unlikely to go wrong.

n Construction:

Category 6 cables use 0.59 mm (23AWG) plain annealed copper, polyethylene

insulated twisted pairs, laid up around an internal support X-spline within a

PVC jacket. The internal support spline ensures crosstalk advantages, while

providing support for individual pairs and the cable as a whole.

An ideal pair is comprised of two perfectly balanced

insulated conductors that are mirror images of each other. To achieve this

balance, the centre-to-centre distance, or centricity between the copper

conductors of a pair should remain fixed and constant along the length of the

cable. With Category 6 standards pushing the boundaries of performance for UTP,

users are relying heavily on installation techniques to maintain good

performance from their installed system. Typically, when cables are installed

they are pulled on, bent around corners and may kink. Each of these factors

changes the physical properties of the cable, which in turn can degrade the

cables’ electrical performance. Thus it is important to seek products with

construction that is forgiving to varied installation practices such as coiling,

pulling around bends, and pulling from the box.

n Consider

the Environment: When comparing various types of cables, it must be

remembered that the results would be dependent on the implementations, such as

the network cards, hubs, and other devices used and depend on the factors like

the cabling distance, physical location, and environmental effects. For

instance, fiber-optic cable maybe costly on a per-foot basis, but may work out

to be cost-effective a cable has to run for several kilometers. All depends on

the repeaters needed to run the cable. Today Gigabit Ethernet has been approved

for fiber optic cable in 550M and 5 km lengths and for Category 5 copper cable

up to 100 meters. It is important to keep in mind the design consideration of a

structured cabling system including building entrance, equipment room, backbone

cables, intermediate and main cross-connects, mechanical terminations and patch

cords or jumpers used for backbone-to-backbone cross-connection.

n Engage

Consultants: Have a draft plan of action and check if the proposed network

architecture is practical. Engaging consultants will involve expenditure, but

may speed the deployment process up by allowing key issues to be quickly

identified, and questions to be directly and independently answered.

n Go

for Good Integrators: Considering all these parameters, it is advisable to

go for solution providers who have good track record of support and assistance

with a good list of channel partners, installers, and certified professionals.

They could also help in the documentation process. Documentation will help an

unfamiliar person to quickly grasp the network topology.

They can also enable the network to grow in a planned and

well- structured manner. The final performance of your network is highly

dependent upon installation practices. Simple techniques like following the ½

inch rule ("Never untwist pairs more than half an inch at the point of

termination") can go a long way in ensuring superior network performance.

So ensure that the SI you choose is known to pay attention to detail.

EXPERTS PANEL Asish Chand, country manager, Belden DS Nagendra, country sales manager, PremisNET, Krone Communications KK Shetty, country manager, NETCONNECT Solutions Division, Tyco Electronics Sreelal Nellary (RCDD), regional sales and technical support manager, Panduit Int’l Corp.