Quality of (Your) Service

All of a sudden a pair of acronyms that for years circulated in small network circles have now become the hot lingo. I'm talking about SLAs and QoS, or service-level agreements and quality of service.

Though neither necessarily refers to any particular "agreement" or "service," the terms are typically applied to the provisioning of network services by some service provider to some user company. In big companies, the IT department itself becomes the service provider, with the user departments being the recipients of various network services.

Very often, SLAs and QoS refer ultimately to network uptime or network access. Do my users have the bandwidth they need when they need it? Are the Web servers fully functional and accessible to customers or to internal users during peak access times? What will an SLA look like in a couple of years when users will want to work with much more video and multimedia over the network? How do we write a good SLA to protect ourselves? Can QoS even be measured? If so, by whom?

The fact is, we are quickly exiting the computing era known as client/server -- which succeeded the PC era, which itself succeeded the host-centric era -- and vaulting into the network computing era. If the network is not operating optimally, or not at all in the worst case, computing resources suffer or go away. And with businesses utterly dependent on information systems, so goes the business as well.

Thus, the quality and consistency of network service comes front and center. The problem is that what passes for quality connections and consistent service is itself rapidly changing. So how do you begin to think about writing SLAs and negotiating for QoS?

You do have some things in your control. Take, for example, the most pedestrian of technologies, your uninterruptible power supply (UPS). The network service providers will often write SLAs that are linked to the degree to which you and your shop have guaranteed uptime with a highly functional if not redundant UPS. The better you take care of this plumbing matter, the more customer-friendly an SLA you are likely to negotiate.

Also, many IT managers have attacked their network access problems by throwing large amounts of often expensive bandwidth at them. Understand that as an alternative to this costly scenario, QoS technology really constitutes an attempt to find a way to categorize your network traffic and then to ensure that, for certain categories, traffic will always flow across the network at the service levels the users are entitled to get -- no matter what the departmentwide contention for network access might be.

These QoS strategies and mechanisms bring you, the IT professional, into a partnership with the user departments. Together, you figure out in advance a sort of bandwidth triage based on greatest bandwidth needs of discrete groups of users.

What you will start to realize is that the different technologies out there, such as frame relay and ATM, are optimized for different network applications, such as voice, video or just plain old transaction processing.

However, you'll realize that although you can write what looks like a sound SLA, in the end it is very difficult to know if your service provider is living up to the SLA. Let's say you have contracted with your Internet service provider (ISP) for a certain amount of bandwidth and Internet access for certain user departments at certain times of the day. Other than situations where the network grossly bogs down or shuts down completely, can you know what level of service you are really getting?

Increasingly, yes, you can. There are a number of vendors, including big ones such as Cisco Systems Inc. and some smaller ones such as Xedia Corp. and Packeteer Inc., that are peddling devices that ISPs can use to deliver the service levels they said they'd deliver and users can deploy to ensure they get what they are paying for.

But no matter where you may be in the IT structure, you owe it to yourself and your company to rapidly familiarize yourself with the dynamic issues and challenges in the SLA and QoS area, because they are not just for network professionals. On the contrary, QoS guarantees may represent the single biggest challenge for developing the networks of tomorrow.

Your worth and value to the company may come down to your ability to avoid network congestion, to integrate both legacy and "new wave" traffic such as multimedia, and to create an environment characterized by (to steal a phrase from Karl Marx) "to each according to his needs." That means working in close concert with the users to ration what is increasingly a scarce and expensive resource: network bandwidth. -- Bill Laberis is president of Bill Laberis Associates Inc. (Holliston, Mass.) and former editor-in-chief of Computerworld. Contact him at bill@laberis.com.