Heavy-Duty Networking

Upgrading a copper (copper) unshielded twisted pair (UTP) network to be able to transmit 10 gigabits per second (Gbps) per IEEE’s Ethernet standard 802.3an requires some deliberation. You need to know how the network functions, what it is composed of, why you would upgrade it and if an upgrade to 10 Gbps is necessary for the type of business it is being used/planned for. Depending on a company’s five- or 10-year plan, it may be overkill.

How an Ethernet network works

According to technical information on HowStuffWorks.com, a single shared cable can serve as the basis for a complete Ethernet network. However, in some cases, there are practical limits to the size of an Ethernet network. A primary concern is the length of the shared cable. Electrical signals propagate along a cable very quickly, but they weaken as they travel. And electrical interference from neighboring devices (fluorescent lights, for example) can scramble the signal.

What constitutes an Ethernet network

Ethernet is a physical method of cabling that connects devices on the local area network (LAN), and standards govern communication on the cable. The most relevant standard is IEEE 802.3. Over the years, the Institute of Electrical and Electronics Engineers (IEEE) has set various standards (802.3ae, 802.3an, etc.), which are applicable based on a network’s specs. An Ethernet network must comply with its appropriate standard.

IEEE knew the physical layer needed to be able to transmit 10 Gbps, or the equipment’s capability wouldn’t matter. So, IEEE teamed up with the Telecommunications Industry Association (TIA) to develop a performance standard for a 10 Gbps Ethernet-capable physical layer that cabling manufacturers could follow to build products. TIA did so, and IEEE adopted its information and came out with IEEE 802.3ak, IEEE 802.3ae, and IEEE 802.3an.

Why upgrade to 10 Gbps?

If we find ourselves easily working and functioning business-wise on 100 BASE-T (copper) systems, it may seem unnecessary to install a structured cabling system with the high capacity 10GBASE-T delivers. However, the world of Ethernet is constantly evolving, and many organizations are looking to the benefits of 10 Gbps Ethernet to support higher speeds across the entire network. Being interoperable and scalable, 10 Gbps Ethernet is an ideal solution for organizations with growing bandwidth needs. Furthermore, 10 Gbps applications are best used in data centers, high-end workstations and Web-enabling applications. Some examples follow:

• Data-center backup/disaster recovery

• Computer cluster farms that transfer data at high speeds

• Network-attached storage (NAS) and storage-area networks (SAN) to improve network efficiency and manageability

• Scientific modeling file transfers between workstations (CAD drawings, 3-D images, DNA sequencing)

• High-resolution medical imagery file transfers

• Business-management applications (Oracle or SAP)

• Media viewing between workstations

• Live video and/or audio broadcasting over the Internet for training

• Voice over the data network cabling to the Internet or voice over Internet protocol (VoIP)

• Digital video conferencing

• High-definition video and/or audio e-mails

Consider upgrading to 10 Gbps in two ways—one from the copper standpoint and the other from the fiber standpoint.

10 Gbps vs. UTP copper cabling

Ten Gbps performs for 100 meters over augmented Category 6a cabling or Class EA cabling—a four-connector, 100-meter channel at 500 MHz.

TIA’s new standard for Cat 6a is 568-B.2, Addendum 10, and it mates up with the IEEE 802.3an 10GBASE-T standard to support 10 Gbps data rates using balanced twisted-pair copper cabling. While the standard recognized that Cat 6 cabling systems could support 10 Gbps Ethernet over limited distances (37–55 meters), the new augmented Cat 6 copper cabling systems had to support 10 Gbps data rates up to 100 meters—the No. 1 goal of a structured cabling system.

The standard also includes requirements for alien crosstalk up to 500 MHz. Alien crosstalk is the main electrical parameter that can interfere with 10 Gbps Ethernet performance over a UTP copper structured cabling system. It is noise (a coupled signal) coming from a signal in a neighboring cable. Canceling alien crosstalk has proved to be very difficult—the internal channel noise can be done, but noise from the outside is extremely difficult. This is where the new Cat 6a UTP cable comes in to support a 10 Gbps data rate. The improvements include cable separation in bundles or added foil tape, and new connectors were designed so that the improvement achieved by the Cat 6a cable itself is not lost in the channel. The components and cable together support today’s high-bandwidth applications.

A building’s cabling can support a company’s users as well as the company’s data center. If a company has standards-compliant Cat 5 or 5e already, it can have 1 Gbps transmission and can get 10 Gbps for distances shorter than 100 meters. If Cat 5/5e is mixed with Cat 6, it will not automatically get up to 10 Gbps. It will get the lowest category of cabling—cable and connectors—for the network capability.

If a company wants 10 Gbps to work for 15 meters, it can upgrade to twinaxial coax in the data center. If a company wants 10 Gbps to work for 100 meters, it will have to consider upgrading the user community to Cat 6a or a Cat 7 (Class F) cable from Europe.

Be aware that when the customer identifies that it wants to use Cat 6 or 6a cabling, you may find most of its users will not be using high-speed applications, such as AutoCAD or imaging, and that the additional bandwidth in Cat 6a cable would be unnecessary. But, if justifiable, the cost should be considered very carefully. Cat 6 UTP is typically a 10 to 25 percent premium over Cat 5e. Then, Cat 6e can be 50 percent more expensive than Cat 6. Although pricing will come down in a year or two as production increases, predictions are that Cat 6a demands will be low enough that pricing will remain high for some time. There also is the fact that the Cat 6a cable diameter is larger and may not fit well into existing pathways.

10 gigabit Ethernet performance over fiber

Another viewpoint that has become popular is to explore fiber versus copper UTP. The electronics are available now to support it, versus waiting for Cat 6a (specified to go to 10 Gbps) hardware. The unshielded or shielded copper cable is a larger diameter (although some coming out now have a smaller diameter) that may have pathway and space problems; closet space is reduced with fiber.

With the reduced cost of Internet protocol (IP) technology, all the information can end up on the data network (voice, video, audio, etc.). For instance, data already is traveling over a company’s network. The phone is now digital. Video also can be sent over the data network. The data network is becoming the network for everything. However, if a company’s voice, data and video all end up over the corporate network and more applications arrive in the future, maybe the Cat 6a UTP network won’t be enough. If more applications become digital, the gigabit pipe over Cat 6a copper cabling won’t be big enough. Fiber may be the solution.

With the added ability to install centralized fiber right to the work-area jack, the cabling is simplified, and even the telecommunications room/closet can be smaller. These are future-based scenarios substantial enough to consider fiber. Infrastructures planned for new buildings are mostly Cat 6 copper and 50-micron fiber. Some future-proofing installations are using the foil-shielded Cat 6, which is designated by the F/UTP suffix. For projects specified now, the trend is toward the foil-shielded Cat 6 or augmented Cat 6 and 850 nm laser--optimized 50-micron fiber, according to Herb Congdon, chair of TIA TR 42—User Premises Telecom, Cabling Infrastructure and Secretary of TR 42.1—Commercial Building Cabling. (For more information on this fiber versus copper debate, see page 96.)

New wiring and remodel projects

Current new and remodeling projects are specifying 50/125 micron multimode laser-optimized fiber between telecommunications rooms and Cat 6 for station cable from the telecom room to the work-area outlet. Fiber can be specified to the desktop (FTTD) when there is a compelling need for either very high bandwidth or when security and distance are primary concerns.

Contractors should provide retrofit customers with a per-unit price for a standard telecommunications outlet (three or four jacks), including jacks, cable, patch panel, patch/station cords and testing, according to technical information on Cat 6a costs and projects provided by Glenn Sexton, vice chair of TR 42.1—Commercial Building Cabling.

As far as 10 Gbps goes, the risk in the decision-making process is eliminated because now there is a standard for the 10 Gbps PHY: TIA 568-B.2, Addendum 10 will later be included in the updated TIA 568-C.2. And remember, files keep getting bigger. Newer applications will need more bandwidth to work properly. There will be more users transferring big files and running bandwidth-intensive network applications simultaneously, and higher-speed switches will be in the data center to combine the traffic from desktops and servers that already are running 1 Gbps.

MICHELSON, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards. Contact her at www.bcsreports.com or randm@volcano.net.

About the Author

Marilyn Michelson

Freelance Writer
Marilyn Michelson, president of Jackson, Calif.-based Business Communication Services and publisher of the BCS Reports, is an expert in TIA/EIA performance standards.

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