One of my first bosses in the tech publishing business once told me some statistic about how times a year Golf Digest runs an article on how to correct your slice. Why don't they just run one story that explains it all, and be done with it? Because people keep slicing the ball.That's always the way it is with network troubleshooting and quality of service. As far as I'm aware, nobody's discovered any new problems that have started to go wrong in networks; but at the same time, the old problems aren't going away. So you offer the same reminders, hopefully garnished with new, ever-more subtle and experience-based tips. And increasingly, there are vendors in this space building management products that aim to help you do this troubleshooting.
Here are few examples from VoiceCon San Francisco presentations:
* John Bartlett's tips on cleaning up the network: From his QOS/QOE presentation, John calls out duplex mismatch (i.e., configured for half-duplex at one end of the line, and full duplex at the other). I think this was literally the first thing I ever heard anyone single out as a major network issue in voice over IP, years ago. It's still a problem--"this is everywhere!" John says in his slides.
And I couldn't wait to tell Matt Brunk about this bullet point, which John cited as another thing to clean up: "Long Ethernet cables." See, Matt was right.
Another thing John mentions is Cat 3 Ethernet cables. This was an issue for the Illinois hospital that I blogged about recently, and I think it points to the fact that there is, in fact, still a fair amount of outdated infrastructure out there.
* Ron Trunk's troubleshooting session: Ron Trunk of Chesapeake Netcraftsmen is doing a two-hour "deep dive" on troubleshooting, and again, it's not like they suddenly discovered a whole new way for networks to get messed up. But Ron's slides, besides having the best opening of any presentation I've seen in a long time, offer a very clear, understandable review of problems and solutions.
And the problem he cites as the biggest source of trouble is configuration problems, which he says have the greatest impact on network stability and faults. According to Ron's slides, the majority of network problems are due to configuration mistakes. But here was the line that really hit home: "Impossible to get to five-nines without it [i.e., config management]". So if you're not doing effective configuration management, you've doomed yourself to failure before you even start.
That's just a couple of examples of some of the material we've got on running the network for VOIP. The topic is as important as it's ever been.
