DeterminismBy CWNP On 08/17/2009 - 13 Comments
Call it what you will: Deterministic, Utility, or Automatic. I don't really care what you call it if you can make Wi-Fi "just work." Every vendor will tell you a different story to tell on how to build "Wi-Fi that works" based on their own networking philosophy and feature sets, and every network administrator has a different view of what "Wi-Fi that works" means.My current view of deterministic Wi-Fi is that vendors should say what they offer and know that what they offer will work as described. Past that, the best anyone could hope for (in today's market) is for a vendor to offer enough features (that work as described) to give wireless clients a controllable and measureable amount of service, whether you're talking about bandwidth/throughput or some other measureable parameter. What would be even better would be the ability to offer actions above and beyond "service guarantees" that could assist those clients that are not receiving the guaranteed service level.
There are many parts to offering such deterministic service (e.g. Radio Resource Management, L2 QoS, and Air Time Fairness). Some vendors have all of the features required to pull this off, and some do not. Some vendors' gear is strong in one area while weak in another. Whatever the case, utilitarian Wi-Fi still seems a bit elusive. I'm guessing that the first evidence of "Wi-Fi as a utility" will come when a vendor can offer an SLA. Not an SLA based on prioritizing one type of traffic over another, but rather an SLA based on offering a set of service parameters (throughput as a minimum) to user groups.
As an example, the IT dept might need to be able to give each sales person 1 Mbps while giving each marketing person 2 Mbps. That, in and of itself, is easily done - it's called Role Based Access Control (RBAC) - and every vendor supports it. What's not supported by every vendor is being able to configure these user groups to get a level of service, monitoring that level of service, and then for users who do not meet the guaranteed service level, one or more remedies are offered to assist that user in meeting the SLA. The difference is the offered SLA, monitoring, and remedy of it all. I'm not currently aware of anyone doing this... If they are, and I don't know about it, please post to let me know.
Another issue is the action a vendor might take in order to help a single user's station meet the SLA when the monitoring mechanism says there's a problem where the station is falling short of the SLA. There's a variety of things the vendor could do, but which one(s) make the most sense? I'd love to hear from you on this one!
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