I’m currently studying/practicing for the Cisco 642-642 QoS exam, and I’ve gotta say, it’s opened up an entirely new toolset for me. I’m but a mere enterprise admin, but I’ve seen a lot of routers and switches in my day, and it’s rare that I’ve seen anything (configuration-wise) that’s truly difficult. We’ve all got our own little configuration quirks (given a device with a legacy configuration at $dayJob, I can likely tell you who configured it within a 95% confidence interval*) that we’ve either picked up from our peers — or on our own and thought “neat, I’m going to try that everywhere!” — but this is the first “feature” I’ve seen that requires some truly in-depth planning; I’ve no doubt this perceived difficulty contributes to my lack of having never seen it in production, so I’ll likely spend some time in an upcoming post ruminating over some of the reasons for or against QoS deployment in enterprise networks.**
But first up, a quick note on what actually constitutes a “small link,” as far as Cisco documentation is concerned. I say Cisco doc, but there is math involved and I believe the concepts to be vendor-independent.
But before that, there’s a hockey game on. ^_^
*We still have some routers that are explictly denying IP protocols 53, 55, 77, 103 ingress on all interfaces, for anyone with memories stretching back a few years: http://www.cisco.com/warp/public/707/cisco-sa-20030717-blocked.shtml
**I make the distinction because those with service provider backgrounds have the luxury of bandwidth; bandwidth can solve any QoS-related problem, but I think there’s still a home for the concepts in MPLS VPN networks.
