QoS has been on my mind lately.

Why?

I suppose there are a number of reasons.

We’re in the process of re-architecting our data network at York. We’re starting off by adding redundancy in various ways, and anticipate the need to address QoS in preparing for our future deployment of a VoIP service.

Of course, that doesn’t mean we don’t already have VoIP or VoIP-like protocols already present on our existing undifferentiated network. In addition to Skype, there are groups that have already embraced videoconferencing solutions that make use of protocols like RTP. And given that there’s already a Top 50 list of Open Source VoIP applications to choose from, I’m sure these aren’t the only examples of VoIP-like applications on our network. 

At the moment, I have more questions about QoS than answers. 

For example:

• If we introduce protocol-based QoS, won’t this provide any application using the protocol access to a differentiated QoS? I sense that QoS can be applied in a very granular fashion, but do I really want to turn my entire team of network specialists into QoS specialists? (From an operational perspective, I know I can’t afford to!)
• When is the right time to introduce QoS? Users are clamoring for QoS ASAP, as it’s often perceived as a panacea – a panacea that often masks the root cause of what really ails them … From a routing and switching perspective, do we wait for tangible signs of congestion, before implementing QoS? I certainly have the impression that others managing Campus as well as regional networks plan to do this. 
• And what about standards? QoS isn’t baked into IPv4, but there are some implementations that promote interoperability between vendors. Should MPLS, used frequently in service providers’ networks, be employed as a vehicle for QoS in the Campus network context? 
• QoS presupposes that use is to be made of an existing network. Completely segmenting networks, i.e., dedicating a network to a VoIP deployment, is also an option. An option that has the potential to bypass the need for QoS. 

I know that as I dig deeper into the collective brain trust answers, and more questions, will emerge. 

And even though there are a number of successful deployments of VoIP that can be pointed to, there still seems to be a need to have a deeper discussion on QoS – starting from a strategic level. 

As I reflect more and more on QoS I’m thinking that a suitably targeted BoF, at CANHEIT 2008 for example, might provide a fertile setting for an honest discussion.