Assessing the bandwidth issue in your LAN

As more applications come onto the local area network (LAN), it is time to look into simple and immediate ways to expand the network's ability to take on heavier traffic.

As more applications come onto the local area network (LAN), it is time to look into simple and immediate ways to expand the network’s ability to take on heavier traffic.

The argument is simple: More bandwidth means that more information gets around, thus more work gets done more efficiently. But the issue facing most network and IT managers is which technology to bet on for the network infrastructure--that ‘invisible’ enabler that most organizations have come to take for granted.

Today in Asia Pacific, two main technologies come to mind when discussing bandwidth for the LAN backbone: Ethernet and ATM (asynchronous transfer mode).

Fast Ethernet (100 Mbps) has been the mainstay protocol for the modern LAN, and in many situations, it continues to provide the reliability and speed required to the desktop. As bandwidth-intensive applications (for example, video on demand and other multimedia and collaborative applications) start crowding onto the LAN, there are doubts whether Fast Ethernet can continue to deliver the reliability and performance to which clients have become accustomed.

ATM technology, on the other hand, even with its high level of reliability, has already lost its appeal as an LAN backbone technology in the US, and is starting to head down the same road in this region. Price is still the biggest hurdle for ATM, as well as the complexities involved in grafting together ATM and Ethernet technologies onto the same LAN.

So what choices does a network manager have, especially when faced with a LAN that’s about to implode at any time, and a tight infrastructure budget? Up till recently, Gigabit Ethernet could only really be implemented on either balanced, shielded copper cable or optical fiber cables. Neither option was practical in terms of cost or implementation, since most organizations would already have an extensive Cat 5 copper wiring infrastructure in place to support their Fast Ethernet

Fiber, of course, has its advantages: It travels longer distances, up to 5km, depending on core diameter and is more secure, especially when applied over a wide area infrastructure. It also has a lower bit error rate (BER), thus meeting most Quality of Service (QoS) requirements for high-bandwidth applications such as video-conferencing.

However, fiber, has its disadvantages. Installation is comparatively difficult and costly. While it is a solution for certain niche business needs, it doesn’t provide a solution that is cost-effective for most companies.

Copper gathers momentum
Super high-capacity copper wiring (Cat 6 and above) is an alternative to optical fiber--except that the cost of ripping out and replacing the existing Cat 5 infrastructure can be as prohibitive as installing fiber. At any rate, few companies would choose to put up with the disruption this causes.

Now, however, it is not only possible, but also far simpler and more practical, to run Gigabit Ethernet over existing Cat 5 copper wiring. This can achieve an almost immediate tenfold increase in LAN capacity over Fast Ethernet, and keep costs down. Gigabit over copper provides affordable, high-performing architectures for increased network throughput due to increased backbone bandwidth.

Winning formula
Why is its rapid adoption virtually ensured?

In the design of any LAN, cabling is meant to have the longest life cycle. The high cost of ripping out existing cabling infrastructure discourages most companies from installing new cabling. While fiber costs 30 to 50 percent more than copper cables, Gigabit over copper is available at a low cost of acquisition and ownership.

Most industry watchers predict that despite the inroads fiber is making, copper will remain the pervasive infrastructure, with 84 percent of LAN ports remaining copper even by 2004.

Gigabit over copper has no significant reliability or performance issues when compared with gigabit over fiber. Copper’s higher BER is overcome by the larger bandwidth, which more than makes up for the shortcoming. No decisions are easy when it comes to assessing the current and future needs of a LAN, being able to predict (and prevent) bottlenecks, and ensuring that virtually any future application will run smoothly to the satisfaction of the organization’s network clients.

Which technology is the better bet depends first and foremost on the overall network design and its future requirements. If the IT manager prefers a single centralized location covering a localized multi-site campus for all networking equipment, then the fiber may be a better option, due to its ability to travel longer distances (of up to 5km, depending on the size of the core diameter).

On the other hand, if the company already has wiring closets spread throughout the office or building, then copper is the logical and economical solution. The split wiring closet stacks using switched Gigabit over copper enable increased backbone bandwidth. Gigabit over copper excels in inter-departmental connections as it is a natural evolution of bandwidth over the same media.

Another consideration IT managers always need to look at is how to future-proof the network. Some questions to take note of when assessing this include: • Will the company outsource IT requirements in the future, such as turning to ASPs?
• Will the organization turn to data-intensive applications in the future, such as multimedia, video on the LAN or VoIP? Will these applications require high security?
• What monetary and human resources does the IT manager have for IT investments?

Conclusion
Gigabit Ethernet over copper is redefining high-speed networking by providing high-performance connectivity over existing Category 5 UTP cabling. It is ideal for growing enterprise networks because of its affordability, simplicity and ease of installation and maintenance.

In evaluating the right gigabit solution, the IT manager should search for switches and NICs that are affordable and simple to use, and those that are reliable and sophisticated enough to meet growing business requirements. Most of all, companies should not have to pay extra for the complexity that many vendors have failed to remove from their products.

Gigabit implementation should be simple.

Robert Chu is 3Com South Asia vice president.