We spend a lot of time providing troubleshooting assistance to our clients. If one of their subscribers has opened a trouble ticket, and our client is having a hard time resolving the issue, they can ask us for help.
We’ve been troubleshooting problems in voice networks for many years. Although the problems can often be complex to solve, the most critical step occurs right at the start. If you start your investigation by asking these 3 questions, you’ll set yourself up well for success.
If you’re an experienced voice engineer, there may be nothing new for you here – but I’ll bet you wish other people followed this process. So print this out and give it as a friendly gift to your customer service agents. 🙂
#1. What exactly happened?
So many trouble tickets say things like “the call failed”. That’s a good starting point, but to really understand a problem we need much more than that.
- What exactly did you do?
- What exactly happened after you did it? What did you hear? What did you see on the phone display?
- What were you expecting to happen? How was this different?
- Can you tell me the number you dialed from, the digits you dialed, and what time you did this?
#2. Does this problem always happen?
By asking this you’re actually trying to learn a couple of different things.
Did something change which caused the problem to start happening? Maybe the problem has never happened before, but starting today it happens all the time. Perhaps that coincides with a maintenance event which could be the cause.
Is the problem reproducible? If you have an issue that happens 100% of the time your chances of solving it quickly are high. You can easily capture diagnostics, observe the issue, try tweaking some settings and easily see if things improve.
But if a problem happens only occasionally the process will be much tougher. If it doesn’t happen every time, try to find out how often. 1 in 5 calls? 1 in 10 calls? 1 in 100 calls? This will have a big impact on your troubleshooting approach, the factors you consider, and your ability to verify if you’ve fixed the issue.
#3. What was different about this situation?
Unless this phone has only just been installed, it’s likely that not every call fails for this subscriber. So dig into that – what is different about this call that could be relevant? If they’re trying to use an advanced feature (e.g. call transfer), try to find a similar situation that works fine.
- Have you made other calls today that worked? If so, when?
- Have you called this same number successfully before? When was that?
- Is there a similar scenario that works correctly? Does the same thing happen on your neighbor’s phone?
- What if you make a small change to the scenario? Does the problem still happen?
Ideal Troubleshooting Scenario
In an ideal scenario, you’ll be able to narrow down the problem to a specific scenario with specific features, and compare it to another similar scenario that works just fine. You can then “split the difference” to identify the specific aspect of this situation that’s the root cause. You want the simplest possible failure scenario.
If you have a 100% reproducible issue you can hopefully gather diagnostics, and understand what each device in the call path is doing, and where the problem is introduced.
Nightmare Troubleshooting Scenario
By contrast, you may find yourself with a problem that happens rarely, but often enough to cause upset – and with no apparent pattern to the occurrences.
In this scenario it’s important to gather data. Record everything you can about the situations where the issue occurs, and (over time) figure out what the bad calls have in common. You’ll also want to find a way to capture traces of some bad calls – either through an “always on” diagnostic tool, or by making repeated test calls until you reproduce the issue.
Regardless of the scenario – Ideal or Nightmare – by asking these 3 questions up front, you’ll put yourself on the right path to narrowing down the focus of your inquiry, and hopefully bring the issue to a speedy resolution.