The Case For More Granular Network QoS

Network quality of service is a strategy that strives for consistent and predictable performance for the various types of traffic traversing the network. From both business and IT perspectives, the desire is to deliver consistent application and communications performance over the network.

Network administrators implement QoS by setting priorities for video, audio and data traffic on the network. However, as more companies move to video and VoIP, broad-based QoS settings may not be comprehensive or granular enough to meet business or customer needs.

“Most enterprises either don’t do QoS or they do it, but only to the bare minimum,” says Deb Smith, an industry consultant. “Instead, they just trust the presets for QoS on their network devices to do the work.”

Smith noted that if all you need to do in your company is prioritize VoIP over other traffic, sticking with vendor defaults on network equipment for QoS might be enough. Unfortunately, most companies today must also prioritize video, critical applications and content downloads--and they must do this at the same time they assess traffic usage patterns so that they continue to optimize their networks for all of the traffic traversing them.

“You’re at risk if you simply trust what your network hardware vendors have established as defaults for QoS on their equipment,” says Smith. “This is when it becomes vital for IT itself to classify and to prioritize network traffic throughput for critical applications and also for services such as VoIP.”

Obstacles To Network QoS

So if a network QoS strategy is so important, why aren’t more companies doing it? There are several reasons, including time constraints. Network administrators and technicians already have full task lists. A full-blown QoS study, followed by policy development and implementation, is a non-trivial undertaking, so it’s easy to sit back and let the network vendor equipment defaults do the QoS work.

Another reason is that many network administrators and technicians lack the QoS skills (and methodology) needed to develop a network QoS that specifically fits the profile of applications and services their corporate networks run.

“There can be real disconnects, especially with the voice side of the staff, since they are used to having their own environment for telephony and not having to share resources on a network that also carries other services,” says Smith.

In addition, many network professionals focus their duties on the overall technical performance of their networks, and not necessarily on business priorities for each application and service running over the network. In short, if the network is performing at an overall acceptable level, the network administrator considers network SLAs as “met.”

[Read how a health care provider monitors quality of service on its network to ensure high-quality telemedicine, video and telephony service for patients in rural areas in "QoS Boosts Health Of Telemedicine Network."]

In a more granularly defined QoS model, however, corporate communication requirements are broken down by traffic types within the network and then translated into predictable and repeatable performance results that the business can understand.

For example, if you are a healthcare agency providing telemedicine services, you might set an SLA that only so many telephone calls can be placed when telemedicine applications are in use. SLAs that can translate network QoS into common business outcomes are useful in budgeting sessions because they give IT business justification when it fights for greater bandwidth within the context of services the business needs.

Developing A Network QoS Strategy

Of course, defining an internal network QoS that goes beyond vendor presets to address the needs of the business can be a daunting task.

“It’s a step-by-step process,” says Smith. “First, companies need to look at their network needs and make sure that all equipment is upgraded to the latest levels of software and firmware. They also need to look at the various types of traffic the network is carrying and then break this traffic into categories, such as voice, video and various critical applications.”

Once this categorization is done, IT should meet with business stakeholders to gain consensus over how services and applications should be prioritized, and what the expected SLA levels--expressed in business terms-- should be for each.

“It takes time and money to develop an internal network QoS, but, like anything else, network QoS is an investment,” says Smith.

It’s also likely to become a greater corporate priority as network performance assumes a larger role in the performance of enterprise applications and services.

[Get deep insight into how to structure QoS in a Cisco environment that runs converged voice, video and data in Ethan Banks' workshop "How To Set Up Network QoS for Voice, Video & Data" at Interop New York Sept. 30-Oct. 4. Register today!]