As we are constantly working to prevent issues like the no-audio condition that some of our customers experienced last week, I realized that it might be a good idea to take a minute and explain a bit about how the phone networks work in general, and how they interconnect with Junction Networks.
All telephone traffic - either calls that originate from or terminate to a phone number are carried by the PSTN, or Public Switched Telephony Network. If you really simplify the network, you can imagine that your phone is connected to a wire that runs to a central office of the Local Exchange Carrier (LEC). The central office handles a set of area codes and exchanges (a US phone number consists of a three digit area code, three digit exchange and a four digit extension). To get a call to go between one exchange and another exchange, you have to use an Inter-Exchange Carrier (IXC), also known as a long distance provider. These IXCs know how to get a call from one exchange to another.
So, if I make a call from 212-555-1212 to 415-555-1212 - my local central office in Manhattan says "I can't deliver the call directly to California - what IXC does the caller subscribe to (ATT, Verizon, Time Warner, etc...)" Every Central Office knows how to reach every FCC registered IXC. So, if I was using Verizon, it would give the call to Verizon, who would then send the call via their IXC (long distance) network to the Central Office that handles all 415-555 numbers, which would then terminate the call.
Phone numbers have limitations - every phone is attached to a single CO, which has sole responsibility for that phone number, regardless of the carrier you select. So, if a CO, for some reason, loses its connection to your IXC or if it goes down completely - you can't make or receive calls until it's fixed. That's what causes phone outages.
Toll Free numbers work differently. As part of the breakup of AT&T in 1984, Toll Free numbers were "unbundled" - which meant that any IXC could assign and route toll free numbers. Later on, multi-manager services were added, which allowed a call to be shared between multiple carriers. For large call centers who cared about disaster survivability, this was key. Even today, many large businesses split their 800 traffic between multiple carriers so that if one goes down, calls can be re-routed through the others within a couple of minutes.
Fast forward to today. The Local Exchange Carrier/Central Office system has changed slightly. Now, in many areas around the country, there are competitive local exchange carriers (CLECs) which provide local phone services. Major CLECs include Comcast, Time-Warner, Level 3, RNK and XO. Junction Networks contracts with CLECs all throughout the country to provide inbound (and outbound) phone service. When someone calls a Junction Networks phone number, the caller's Central Office contacts the Central Office that handles the area code and exchange, which sends the call to the appropriate CLEC, which sends the call over to us. When we make an outbound call, we pick the best IXC (we contract with many as well) based on where the call is going (and if there are any issues impacting a specific network).
Most of the problems that impact our clients happen before the call ever gets to us. For example, last week, one of the CLEC interconnects in the midwestern area had a problem which caused calls to come to us with no audio. Unfortunately, at this point - there's nothing we can do. Since the calls are coming from the PSTN to us with no audio, there's no way we can "failover" the call to another CLEC or do some sort of internal magic to somehow make the audio work since it's not coming to us in the first place. Even worse, the PSTN system takes days to move phone numbers from one CLEC to another, so there's not even a fast remedy for us to move calls between networks.