How to cost-justify a network upgrade

Headnote

Hard data on poor network performance helps justify an upgrade, but enabling new business objectives helps even more.

HOW that Y2K is pretty much behind us, many tT shops are considering infrastructure upgrades. This is espedally true as enterprises push to support e-business. However, network upgrades are generally complex and can be very costly, and any network upgrade could disrupt existing services and diminish user productivity, resulting in additional costs.

When considering a network upgrade, first determine if it can be justified. Instead of installing new gizmos every time the technology advances and vendors come knocking, it may be better to wait until users perceive a need for an upgrade, or if a new system could reduce costs.

Unfortunately, there is no all-encompassing formula for justifying network upgrades. "Network planning and upgrade justification is as much an art as a science," says David Rhynas, president of DIR Communications, a network services planning and project management consultancy.

In this article, I'll explain some of the art and more of the science of justifying network upgrades, and show how metrics can be used to support such upgrades. It's sometimes hard to tell whether business drives technology or vice versa. The network upgrade process is frequently a combination of both. I'll start with the technical drivers and then consider the business aspects.

TECHNICAL DRIVERS

The need for speed is probably the most common reason to upgrade a network. This may mean upgrades to hardware, such as a router or the links themselves. If network performance is slow, the first thing to do is look at the links and see if they have sufficient capacity.

"As a rule of thumb, 70 percent utilization on a network link or interface usually signals a need for increased capacity," says Rhynas. If link capacity is suitable, then look for any bottlenecks or choke points in the network that may be the result of insufficient hardware.

Older equipment, such as LAN-to-LAN bridges, is usually the first place to look. In that case, a simple solution may be to replace the equipment rather than upgrade the system.

However, bottlenecks are often the result of increased traffic or senrice load on systems that had previously offered good performance, such as servers or routers. Whether...