There’s been lots of talk about quality of service in LANs, but unless you’re running voice, video or other unforgiving applications, you can probably solve congestion by simply throwing more bandwidth at the problem.
After all, according to IDC, the average worldwide price of a Gigabit Ethernet switch port is US$531 – with some individual prices just a fraction of that – and the cost is projected to continue dropping for the foreseeable future. By 2006 the average price per port will be less than $200, IDC says.
These are affordable prices for many companies, especially if more bandwidth means not having to learn the ins and outs of underlying QoS technologies such as 802.1P and Q, Differentiated Services and type of service. These factors actually make it attractive to avoid implementing QoS altogether if possible.
“The only ones that I see turning on QoS in the LAN are those deploying IP telephony,” says Lawrence Orans, an analyst with Gartner Inc. And even some of those are ducking QoS.
The Auditor General’s office for the state of Arizona has used IP telephony for 225 users for 18 months using Cisco Systems Inc. gear without QoS, says Joe Moore, director of IT services for the office. “We just wanted to try the IP voice and see what we’d have to do about QoS,” Moore says. “So far we haven’t done anything, and we haven’t had any major concerns.” The only problem users report is an occasional echo on the line, and he’s not sure QoS would solve that.
Eventually, Orans warns, QoS may be needed.
“It’s like playing Russian roulette. Five times out of six, you’re going to be okay. Then there will be those times when there’s a lot of congestion on the network and someone picks up the phone, and they get inferior quality.”
With even those who theoretically need it the most avoiding QoS, vendors are trying to make the technology more inviting. Vendors such as 3Com Corp., Cisco Systems Inc. and Alcatel SA include QoS technology in their LAN switches at no extra cost, giving users the option to turn it on. They also are developing QoS management software – available at extra cost – that configures service quality without having to dig into switch-by-switch configuration. This software lets customers set service-quality parameters for certain traffic on a graphical user interface, and then the software takes over to configure the affected switch ports accordingly.
Alcatel next month will ship a new software platform called Policy View with OneTouch that simplifies configuration of QoS for common applications. Among other features, OneTouch has a shortcut for voice traffic that requires network administrators to type the subnet of the IP phones into a field to set up voice-quality service, and that’s it. The software automatically chooses the simplest method to deliver the best possible quality of service, taking into consideration the capabilities of the switches involved. Users don’t have to worry about the underlying technology.
Similarly, Cisco offers Cluster Management Suite to simplify setting QoS, Enterasys Networks Inc. sells NetSight Policy Manager to do the same, and Nortel has configuration wizards as part of its Optivity Policy Server. Users need these policy managers because parameters they can set to control QoS include source-destination addresses, protocol, User Datagram Protocol (UDP) or TCP port number, virtual LAN ID, ethertype values, rate limiting and even time of day. “That’s really too much for the average user,” says John Mead, Nortel’s director of software engineering for its BayStack products.
“All the major players have good quality of service at this time,” especially those that that sell voice and data equipment, such as Alcatel SA, Avaya Inc., Cisco Systems Inc. and Nortel Networks Corp., Orans says. Others, such as Enterasys, support QoS but don’t sell voice gear themselves, he says.
In some environments, network executives need QoS because their end users will find a way to eat up all bandwidth no matter how much there is.
“You’re always going to consume whatever bandwidth you have. I can toss meg[abit] after meg after meg at an [application], and it will be used at 95 percent,” says Brian Young, CIO at Hobart and William Smith colleges in Geneva, N.Y. Increasingly sophisticated students bring more bandwidth-hungry gear to campus each year, he says, so he needed a way to prioritize who gets how much bandwidth when. To do this, the colleges use Enterasys gear.
“We can crank up the delivery of bandwidth to the academic network during classes, and during these times turn down these resources to the residential network. When classrooms are not in their heavy-use time, we can crank up the residential network,” Young says. The college uses videoconferencing to tie a remote author in to talk to a literature class and earlier this year streamed video of varsity lacrosse games.
Young says learning to run QoS was a matter of his network engineer and director of enterprise systems each taking two five-day training courses.
Looking to the future, Young says he hopes to implement an Enterasys feature called User Personalized Networking, which deploys QoS to users instead of ports. Each end user is assigned QoS rights, and when they authenticate to the network their QoS profile is imposed on whatever device they log on from. So if a user worked for the day from a desktop in a different department, that desktop would be assigned a QoS profile to match the user’s. Nortel says that in conjunction with other vendors, it is working on something similar that it plans to announce soon.
Vendors also are looking to integrate this user-linked QoS with wireless networking. Nortel says its goal is for users to log on to a corporate network from a public wireless hot spot and get their traffic handled with the priority they would get on the LAN. Enterasys says it has designed its QoS scheme to evolve to include wireless.
Implementing QoS on multivendor networks is still down the road. Despite being based on standards, QoS implementations vary from vendor to vendor. And because QoS involves mapping certain QoS fields to other QoS fields, interoperability becomes even more complex. So at the moment, users pretty much have to use one vendor’s gear to effectively deploy QoS, Orans says. “Among vendors, we’re not seeing a lot of interest in interoperability, but if you go to a single vendor, you’re all set,” he says.
A cooperative effort among vendors established the QoS Forum in 1999, but the group seems to have run out of gas. Its goal was “to educate the market and facilitate deployment of QoS-enabled IP products and services.” It even had a Web site, www.qosforum.com, which still exists but lacks any information about the QoS Forum. Advances in interoperability will have to come from somewhere else.
