by Anyone who has ever administered a Cisco Unified Communications Manager (AKA Call Manager, or CM) system learns very quickly that there are approximately 17 billion different configuration settings in CM. All of those configuration dials have to be maintained in the right ways to get the system to do what you want.
I’ve taken several Cisco training courses on CM, and I felt like the thing that was missing was a real-world case study of how you setup all the pieces to interact with each other and why. There was no real “best practices” in the classes, just a lot of “this setting does X or Y” without any explanation of why you would choose to do X vs Y.
Read on for exactly that information from documentation I’ve been working on for the CM environment at my job.
When I finished taking those classes, I now had the knowledge I needed to be able to take a look at how our Call Manager environment at $work was configured and understand what everything meant. But first let me give some background on what I was looking at.
Our Call Manager environment had been built several years earlier, with each piece of the system being built by different people without any attempt to standardize the configuration. Those people are all long gone of course. The VOIP consulting company we brought in to work on the system brought their own style of configuration to the system, where by “style” I mean “reinvent how you do things everytime you touch it”. So we brought in a specialist consultant to help them get things right. Then we realized that company was idiots and brought in another company, who did an excellent job of helping us with a major upgrade, but not a very good job of helping us understand how to do things “right”.
So when I took those classes, a large part of the goal was to be able to build ourselves a best practices guide for how to run our system. When the class gave me all of the pieces but none of the big picture, I realized I’d have to invent our standards from scratch. So I went to start digging into how we were currently configured and find out what I liked and didn’t like. The result was something like: “Oh my. OH MY! Wait, how does this work? They did what! We’re USING THIS! OMG! FIX IT NOW!!!!”.
Over the next two months I spent a lot of time working on writing an internal document defining our Call Manager Configuration Standards. Along the way I built some diagrams explaining how core critical pieces of the CM configuration interact with each other. I discussed those documents with some folks outside of $work and had a lot of requests to share the information I had been working on. I asked for and received permission to share them.
Caveats
- These documents are provided as an example. Do not apply these standards without thoroughly reviewing them to make sure they make sense in your environment
- These standards work for us, they won’t work for everyone.
- At least we think they work for us. We’re still in the process of applying these standards, and we consider this standards document a Living Document which will evolve over time as our needs change
- Any feedback on these documents would be appreciated. Questions/comments/concerns, etc. Send feedback to nolan+lopsa@managedandmonitored.net
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