Worse still, it is not the users of these applications who are going to complain about the availability and performance problems that they have wrought. Rather, it will be users of the mainstream business applications--e-mail, database-access and client/server applications--who will scream the loudest. Every time another user fires up his or her RealAudio player, a Notes user will feel the network slowly start to slip away, and you'll take the heat for it.

It is at times like this that congestion control and prioritization become much more than niceties. Rather than dismissing them as unnecessary luxuries that are irrelevant to your network, consider that these services offer what is perhaps the best hope for running a functional network.

Prioritization alone won't eliminate all of your bandwidth blues. If congestion is a real problem for your network, you'll need to address it with bigger network pipes, not just prioritization services. If you're losing packets now, then you'll still lose packets after implementing prioritization services. The difference is that prioritization allows you to decide which packets you're willing to lose. If you're not willing to throw away any of them, you must add bandwidth.

However, if the problem is not sustained congestion but sporadic bursts that do not yet justify the cost of additional bandwidth, your focus should definitely be on using prioritization to ensure smooth operations. In this scenario, you will want to have database queries and client/server data run across the network at higher precedence levels than less-critical traffic.

While many vendors have constructed schemes for implementing prioritization on Ethernet networks, these solutions have been restricted to vendor-specific offerings. With the advent of new bandwidth-sucking technologies like voice over IP and video on demand, the need for cross-vendor prioritization services in heavily utilized networks has become increasingly urgent.

In an effort to address this problem, the IEEE has introduced two drafts intended to provide just this service. The first of these is 802.1p, a draft extension to the 802.1D bridging standard that dictates how prioritization should occur within a MAC (Media Access Control)-layer bridge, regardless of the media in use. Meanwhile, the 802.1Q draft standard for VLANs (virtual LANs) is promising to add prioritization services to Ethernet in particular.

By using 802.1Q-compliant Ethernet frames and 802.1p-compliant switches, it is possible to implement full-featured prioritization services across your entire network, regardless of the topologies in use.