When I was 17, our high school choir embarked on its first ever concert tour to mainland Europe.
We were heading to Salzburg, then on to Italy, including Venice and Lake Garda. To keep costs down, the school hired a coach rather than flying. It was quite an adventure: we travelled from northern England by ferry, then the coach drove overnight to our first destination. The overnight coach journey saved money on a night’s accommodation, got us there faster, and for a group of enthusiastic (if slightly sleep-deprived) teenagers, it all seemed perfectly normal.
The trip itself was fantastic. We sang in some beautiful venues, including St. Mark’s Basilica in Venice, were amazed by the beauty of Lake Garda and developed a strong sense of comradery among the group.
However, it was the journey home that provided the story I’ve remembered most vividly.
As the coach travelled overnight through Europe, most of us were trying to sleep in the impossibly awkward position that only a coach seat can provide, but sometime in the early hours, we began hearing a strange thudding noise.
It seemed to be coming from underneath the floor.
At first, everyone was simply puzzled. Was something loose underneath the coach? Had we hit something? Was there a mechanical problem? Then we thought we could hear shouting mixed in with the banging, although it was difficult to tell over the sound of the engine and the road.
None of it made much sense.
Eventually someone mentioned it to one of our teachers, who spoke to the driver.
The driver immediately pulled over.
It turned out the second driver had been asleep in a sleeper berth beneath the passenger compartment, near the luggage hold. I’d had no idea such a compartment even existed.
Something had gone wrong with the ventilation into the berth, and he was struggling to breathe. The banging we could hear was him desperately hitting the roof of the compartment – our floor – in the hopes that someone would hear him before he suffocated.
Fortunately, the coach stopped in time and the driver was unharmed.
Looking back, what strikes me is how misleading the symptoms were. We heard banging under the floor; we assumed there was a problem with the coach – but the actual problem wasn’t mechanical at all. It was a person, in a part of the system that most of us didn’t even know existed.
Hidden systems create confusing symptoms
Telecommunications systems are remarkably similar.
Customers rarely report the root cause of a problem – instead they report symptoms, or guess at the cause based on a very limited understanding of how things work.
- “I can’t hear anything, the speaker must be broken.”
- “Everything was working until lunchtime.”
- “Only Julie’s phone has a problem.”
- “I hear dial-tone, so everything must be fine.”
Those observations are valuable, but they’re only clues. Solving the problem usually requires more questions, and an expert’s understanding of how the network fits together.
A one-way audio problem may have nothing to do with SIP signaling. Registration failures could be caused by a DNS issue. Intermittent call failures might turn out to be a firewall issue, or routing changes somewhere else in the network. The symptom points you in the right general direction, but not necessarily to the real cause.
Expertise means understanding what you can’t see
Experienced telecom engineers solve problems more quickly not because they’ve memorized more error messages, but because they understand the whole system.
The coach driver immediately recognised what the rest of us couldn’t. He knew there was another compartment beneath the floor. He knew someone was sleeping there. The strange banging suddenly made perfect sense because he understood the hidden parts of the vehicle.
In the same way, an experienced voice engineer doesn’t just know SIP messages or RTP packet flows. They understand how SBCs interact with firewalls, how DNS influences call routing, how media streams follow different paths from signaling, how NAT changes behavior, and where all those hidden dependencies live.
When you understand the architecture, seemingly unrelated symptoms often become surprisingly logical.
Don’t stop at the symptom
It’s tempting, particularly under pressure, to fix the first thing that looks broken, but lasting solutions usually come from asking a different question:
“If these are the symptoms, what underlying issue or change could be causing it?”
Sometimes the answer lies in a completely different layer of the network. Sometimes it’s in a component that nobody has thought about for years. And occasionally, it’s in a part of the system that many people don’t even realize exists.
Once you understand the hidden parts of the system, the mysterious banging under the floor suddenly becomes much easier to explain.
At Award Consulting, we spend a lot of time helping service providers diagnose complex problems in voice networks, where the symptoms and the underlying cause are often separated by several layers of technology. Whether it’s signaling, media, SBC behavior, NAT traversal, or network architecture, understanding the whole system is usually the key to finding the real solution. Don’t hesitate to reach out to us if you need some assistance.
