Copper conundrum

Although the 10GBase-T standard is not expected to be ratified until next year, 10Gigabit Ethernet over copper is garnering a lot of interest in the Middle East, with several vendors bringing products to market. The technology promises to bring affordable high bandwidth passive infrastructure to the enterprise but is it mature enough for network managers to buy the sales pitch?

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By  Simon Duddy Published  May 23, 2005

|~|10jig_m.jpg|~||~|The 10Gigabit bandwagon appears to be well and truly rolling with several vendors releasing unshielded twisted pair (UTP) 10Gigabit solutions, although the 10Gigabit Ethernet over copper standard (10Gbase-T) has not been ratified yet. The UTP products have attracted the lion’s share of attention because of the great difficulty in creating a workable solution due to concerns over alien crosstalk. This is electromagnetic noise that occurs in a cable that runs alongside one or more other signal-carrying cables and can impair performance. Some vendors have persisted with UTP, rather than migrate to shielded solutions for 10Gigabit because UTP is easier to craft, has a large installed base and is cheaper. The UTP products join a plethora of Cat 6 shielded twisted pair (STP), Cat 7 copper and fibre 10Gigabit solutions on the market. All of these solutions have the potential to facilitate the enterprise’s move to 10Gigabit. But does the enterprise really need the extra bandwidth? Many commentators say the enterprise is still getting to grips with the transition from Fast Ethernet to Gigabit Ethernet, with many companies happy with Fast Ethernet on the horizontal. For these companies there is unlikely to be a need to go to 10Gigabit on the backbone, at least until they migrate to Gigabit on the horizontal. However, cabling vendors are stressing that companies should consider the long-term (20-25 years) implications. They say investing in a Gigabit infrastructure now may be short-sighted as demand could exceed capacity within 20 years due to the increasingly bandwidth hungry applications deployed by the enterprise. This places great pressure on the network managers of the Middle East to be able to judge how much bandwidth they will need in the long term. A decision to opt for 10Gigabit should not be taken for granted, as companies using modest PC applications, will thrive on Gigabit or even Fast Ethernet networks for many years to come. One IT professional who has faced this dilemma is Mohammad Abdulwahed, IT manager for the Al Fozan group of companies in Saudi Arabia. Abdulwahed took the view that a 10Gigabit solution offers the necessary headway for the long term development of its new head office. The firm opted for one of the pre-standard UTP solutions, the X10D from Systimax. “We needed performance and bandwidth so we went for the newest technology,” says Abdulwahed. “We have an eleven storey head office in which 7,000 metres of 10Gigabit Ethernet UTP cabling has been installed on the horizontal. We have yet to decide whether to extend this to the vertical also or to go for fibre,” he adds. Future proofing is central to Al Fozan’s strategy as the network currently operates at Gigabit speed. The company feels it will need the extra bandwidth as it takes on more applications such as video in the years to come. For companies looking to invest in 10Gigabit bandwidth, fibre has traditionally been the medium of choice, with copper a relatively new option. While no one can deny the robust performance of fibre, copper is able to muscle its way into the reckoning due to being widely regarded as a more cost-effective choice. Not everyone agrees with this opinion, however. Chris Moore, MENA regional manager for active device manufacturer Extreme Networks believes that similar costs when compared to fibre solutions in some circumstances means it will struggle for uptake. “We do not see a strong trend of 10Gigabit Ethernet copper being used in data centres as normally patch cables are used to connect the servers to the network. Replacing these copper cables with fibre versions is not a big installation issue. Looking at cost, we expect that 10Gigabit Ethernet on copper will be more expensive than short range 10Gigabit Ethernet optics,” says Moore. While some are un-convinced by copper, particularly for short distances, other vendors are holding out the promise of significant cost savings if enterprises opt for copper over fibre, especially for horizontal installations up to 100 metres. “Copper is cheaper than fibre, and it’s not just the cabling, the copper interfaces are also typically three times cheaper than fibre interfaces,” says Craig Tindle, United Arab Emirates (UAE) country manager for Systimax. For reasons of cost effectiveness, most enterprises are looking closely at copper. Choosing copper is not a simple matter though, as many different competing technologies and approaches are trying to grab the attention of network managers, each with its own claim to offer the best solution. The first dilemma that confronts the enterprise is what category of cable to opt for, with solutions available in both Cat 6 and Cat 7 formats. Individual manufacturers will often champion one technology or the other, so network managers should keep the big picture in mind when they talk to vendors. Cat 7 is the more modern design and provides higher bandwidth. Although Cat 7 has not been standardised, the cabling was designed to carry live video and it is widely accepted that it can carry 10Gigabit transmission over at least 100 metres. As it is a shielded solution, it is not susceptible to alien crosstalk, which has proved a formidable challenge to vendors producing UTP Cat6 solutions stretching to 100 metres. “Cat7 has exceptional performance,” says Rob Tansley, regional director for Siemon EMEA. “This is particularly true when looking at our TERA Cat7 system, which is able to deliver 1.2GHz bandwidth over each pair. The segregated pairs in the system mean video, voice and data can be delivered over one cable,” he adds. Cat 7 vendors are emphasising that they have the copper option with the least risk, and are hoping that this will win customers over, despite it being more expensive than Cat 6. “Cat 7 offers an unconditional 20 years warranty with absolutely no risk,” says Tarek Helmy, regional director for Nexans. “Today’s augmented Cat6 UTP solutions are based on incomplete specifications and so have a higher risk. Plus when taking into consideration hidden costs for testing, Cat6 solutions are about the same price as Cat 7,” he adds. On the other hand, Cat 7 has a number of significant drawbacks that have so far limited its uptake. The priority when designing Cat 7 was maximising bandwidth and this has resulted in bulky cables with individually shielded twisted pairs within an overall screen. For these reasons, Cat 7 is more difficult to install than UTP. The system also requires a RJ45 connector to be backwards compatible with Cat 6 based networks. “The connector choice for Cat 7 is confusing. There is a ‘preferred’ connector that is a 10-pin ‘RJ45’, which has not enjoyed much support with Cat 7 proponents or end users,” says Darren Stratton, sales director at Systimax Solutions, Middle East & North Africa. “The second option is a non-RJ45 connector, which has not found much favour with end users since it requires special cords with non-RJ plugs on one end, even for voice applications,” he adds. Cat 6 cabling, in contrast, has the main advantage of easy availability. The vast majority of new cabling that is installed worldwide is Cat 6, which makes it an easy fit for the existing networks of most enterprises. This also makes it an inexpensive option, and when compared with Cat 7 cabling it is smaller and easier to install. Complicating matters further for network professionals, there is also a dichotomy within Cat 6 with vendors generally throwing their weight behind either UTP or STP solutions. This is important for end users to bear in mind, especially with regards to 10Gigabit transmission, where UTP and STP solutions face contrasting challenges. Cat 6 was not originally designed for 10Gigabit speeds and had to be re-designed to mitigate alien crosstalk and support 500MHz bandwidth. It is the limitations inherent in Cat 6 that led vendors to push for augmented Cat 6 (Cat 6a), which is designed to allow vendors to create 10Gigabit UTP solutions for distances up to 100 metres. That said, some vendors say that augmented Cat 6 is not always necessary to run 10Gigabit. For short distances, standard Cat 6 may suffice. The Institute of Electrical and Electronics Engineers (IEEE) has ratified the TSB-155 standard, which provides for 10Gigabit Ethernet over UTP to a maximum distance of 55m on existing Cat 6 cabling. This standard is ideal for specialised installations, such as data centres and storage area networks (SAN), which have higher bandwidth needs but typically short distance requirements. “If you have standard Cat 6 and you want a 10Gigabit solution to perform under 55 metres you should be okay. Plus you can use mitigation techniques. Cables are sensitive to the method of bundling, for example, loose bundling creates less alien crosstalk than tight,” says Paul Kish, director of systems and standards at Belden CDT. Similarly as shielded cabling does not suffer from the effects of alien crosstalk, STP solutions are more readily adaptable to 10Gigabit transmission. Several vendors have put STP 10Gigabit cabling solutions on the market and although, like the UTP version, it is not standardised, there is little controversy over the effectiveness of the solutions. That said, STP solutions tend to be more inflexible and expensive than UTP. Most concern has therefore been focused on pre-standard 10Gigabit UTP products. ADC Krone, Belden, Systimax and Panduit have released solutions and these have drawn attention because the susceptibility of UTP cabling to alien crosstalk. These vendors claim to have solved the alien crosstalk issue but they have met with a barrage of criticism from other vendors. Felice Guarna is the training programme manager for R&M, which has a STP 10Gigabit solution but says it will not release a UTP version until the 10Gbase-T standard is ratified because of alien crosstalk concerns. “We don’t have UTP products because there is no consensus yet. We are a responsible company, and we don’t want to offer something that is not future proof. How can we sell something that could change tomorrow? After all, people are still discussing whether the connector should be changed,” he explains. The more cynical commentators in the marketplace are labeling the 10Gigabit UTP solutions as vendor-led and not in the customers’ best interests. They say that the pre-standard nature of the products coupled with the tough requirements for 10Gigabit transmission make them an excessive risk. Sceptics also say that even if a pre-standard solution is backed by a vendor’s guarantee, this will not cover how the product interacts with components from other vendors. They argue this makes pre-standard products proprietary and promotes vendor lock-in. “Never install a component before it is fully defined, tested and independently verified,” says Aizaz Karjikar, managing director of Heritage Technology, a strategic partner for Turkish cabling vendor HCS in the region. “Installing cables based on not-yet defined parameters, such as alien crosstalk, is careless and unprofessional and may lead to substantial loss of time and money,” he adds. End users are also often cautious about deploying pre-standard solutions, after all very few enterprises want to commit to having a homogeneous passive infrastructure for a 20 year period. Most companies would like the option to mix and match components from different vendors to maximise cost effectiveness. However, this is only possible with standardised products and the consequence of mixing vendors in pre-standard configurations could be disappointing performance. “We do not expect to deploy a solution without the appropriate standards being ratified and due assurances and warranties being provided by the manufacturers,” says Mubeen Khan, network analyst at Zayed University. “However, we are considering 10Gigabit over copper for our new campus, which is a little over 15 months away from completion [which means the standard may be ratified when it opens], therefore we will be monitoring the standards developments very closely,” he adds. End users also need to be aware that there are a variety of standards being created, which have criteria that varies in its stringency. Most IT department staff would look first to the Institute of Electrical and Electronic Engineers (IEEE) for guidance, but there are a number of other respected bodies and the savvy manager will make himself and his team aware of the criteria for each. Many figures in the industry are recommending that users should consider the most stringent requirements, especially as the standard is still in the potentially volatile draft stage. “The proposed International Organisation for Standardisation (ISO) 11801 Class E Edition 2.1 is the most stringent standard,” says Sylvain Bloche, business development manager at Panduit EMEA. “It requires performance out to 625MHz and doesn’t have any relaxations in the slope for internal crosstalk noise. The IEEE and Telecommunications Industry Association (TIA) both have a relaxation in the slope for internal crosstalk noise at 330MHz,” he explains. Testing for alien crosstalk in the field is also a difficulty. Fluke Networks is one of the key vendors providing network testing equipment and while it has a field tester for alien crosstalk, it says the process is proving too time consuming. “We must assume that cables will have to meet alien crosstalk requirements in a worst case scenario unless somebody finds a way to select a representative sample for testing,” says Christian Schillab, segment product manager of infrastructure supervision at Fluke Networks. The vendors that have already released UTP solutions, needless to say, strongly disagree with the assertion that alien crosstalk difficulties are insurmountable in pre-standard products. They also say that the release of products has been prompted by end user demand. “It’s not the manufacturers who are trying to push a new system on to the market, it’s a requirement from network managers to future proof new networks knowing that the active equipment manufacturers will be shipping 10Gbytes/s [copper compatible] equipment as soon as next year,” says Henk Schoeman, regional director for ADC Krone. “Against this backdrop, very few network managers are prepared to take the risk of putting in a network infrastructure now that will be out of date in far less than its design life,” he explains. Vendors are pushing hard to reassure customers that they should not worry about installing pre-standard solutions. Systimax released its X10D solution in late 2004 and says it has a proven track record of releasing successful products pre-standard, so customers should not be concerned. The vendor has also emphasised that its solution exceeds the minimum draft requirements that have been specified by the standards bodies to date and is covered by a 20 year warranty. “For those end users searching for peace of mind, the last milestone reached in UTP cabling was the introduction of the Cat 6 standard in 2001, yet Systimax launched its Cat 6 solution in 1997. Even with the passing of five years, the Systimax Cat 6 product still exceeded the ISO and International Electrotechnical Commission (IEC) specification when it was ratified in 2002,” says Stratton. “Since installed cabling is expected to last for up to 20 years, customers cannot afford to wait for standards ratification before deploying next generation cabling infrastructures that can support today’s applications while anticipating the needs of tomorrow,” he explains. With many new and pre-standard solutions being touted, competence in installation and maintenance is more important than ever. This is due both to uncertainty over specifications and because the pressures of 10Gigabit transmission push Cat 6 right to the edge of its limits. “When preparing to install new copper cabling systems which support high frequencies, enterprises need to realise proper design and implementation is critical,” says Kandasamy Ganesan, divisional director, OnLine Distribution. “This means designers and installers must be fully trained on the design guidelines of the various components in their cabling systems,” he adds. We spoke to most of the cabling vendors in the market in the Middle East and they can be categorised according to the solutions they sell, although many of the vendors sell a variety of products and will look carefully at an enterprise’s situation before recommending an appropriate fit. Systimax, ADC Krone, Panduit and Belden have all released pre-standard UTP solutions, while R&M and Tyco are primarily recommending shielded Cat 6. Siemon and Nexans in turn put Cat 7 solutions to the forefront. Each solution has its own advantages and disadvantages so end users should be wary of following the lead of any one vendor too closely. Nevertheless, for the enterprise looking at building passive networks to last 20 years, 10Gigabit over copper is certainly an enticing option. While the decision to use copper as the basis for 10Gigabit networks may turn out to be a wise one, Network Middle East would advise enterprises to wait until the standard is ratified if possible. If the enterprise cannot wait and decides to opt for pre-standard products, network managers should seek clarifications and watertight guarantees from cabling manufacturers.||**||

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