SIP Trunk? VNO? Cloud PBX? Small Glossary To The Use Of Operators, Integrators, ICTs And Developers

9.4.2022 - 13 min. read

Studying telecom terms

Telecoms can be frustrating, the number of abbreviations and acronyms make understanding of concepts harder than it should be. Although most of the concepts are pretty easy to understand once explained. Indeed, with the right vocabulary, it is very simple to understand what a professional is saying. It is also much easier to market your telco product, select the right provider and grow your telecom business.

Whether you are just getting started into the fantastic telecom world or the voice business or the experienced professional that you need a knowledge refresh, we compile here the most commonly used terms and their explanation.

Let's go

Voice services: That’s a very generic term and it designates a multitude of concepts but to make it simple it is technically defined as the routing of voice conversations either via “PSTN” through the public switched telephone network or “voice over Internet Protocol (VoIP)” through any IP-based network. Business-wise, voice services are defined as services that enable the client to either route the calls from the caller to the callee (“Termination”) or get the calls from any caller in the network to the phone number of the callee (“Collection”). When both termination and collection are provided, the service is said to be “2-Ways” and in this case, it requires at least two things, an interconnection to either the PSTN or VOIP Network (to the world!) and a phone number to be able to be reached by the network.

We mentioned before that VOIP could be other any IP-based Network, but it is important to separate VOIP services that are open by design to the public telephony network and those which are private. With VOIP services open to the phone network anyone can reach you as long as they have your phone number, it’s your regular phone system. In VOIP services on private IP networks like Whatsapp, Viber, Facebook Messenger, Line, or WeChat, you have to be part of the private network to be reachable, which means usually you have to have the right application on your phone basically and you can’t reach someone on Whatsapp with your Wechat app.

We go into further detail on this topic in our article “The voice is dead? Really?”

SIP/WEB RTC/VOIP: Those are different categories and subcategories of Voice routing through the IP Network. VOIP or “voice over Internet Protocol” is the generic term to designate the voice call routing over the IP based Network. Within the VOIP family, you have SIP and WebRTC. SIP or “Session Initiation Protocol” is the voice optimized internet protocol that is used to carry calls between operators worldwide. Web RTC is an HTTP protocol which enables voice services on web browser and mobile application, so like SIP it carries voice calls but it is not used to exchange calls between operators. We did an article on this “What the difference between VOIP, SIP and WebRTC” we let you have a look if you want more details

PSTN: PSTN is the legacy/traditional circuit-switched telephone network, it stands for “public switched telephone network” and it usually works on SS7 protocol. it is generally still accepted as a standard form of communication, however, we see a steady decline in its usage over the last decade because it hasn’t evolved much and isn’t as cost-effective as the VOIP technologies. Most of the national operators are gradually switching to IP-based protocols and switching off their PSTN services. It is also known as the Plain Old Telephone Service (POTS)…

SIP trunk: A SIP trunk is the virtual version of an analog phone line. With SIP trunks, a Voice operator can connect 2 or multiples endpoints. Those endpoints can be low level, like voice gateways between operators, but it can also be an IP Phone, an Application, or an IPBX right in the office. SIP trunk is a “tube” usually between 2 endpoints where SIP phone calls are routed.

PBX: PBX is a private telephone network with a multiline telephone system typically used within a company, and organization or in a business environment. The word itself stands for Private Branch Exchange, where calls can be exchanged internally within the private network of the organization and externally with the public network using different communication channels like Voice over IP, ISDN, or analog. You probably already reached one of your colleagues within your company through her/his “extension” dialing “2374” or dialed “123” to reach the hotel reception from your room. If so you have used a PBX. There are nowadays 4 types of PBX, 2 which are on-premises, in the organization building: the traditional PSTN based PABX, the IPBX using Internet protocols, and 2 which are off-premises, the hosted PBX, which is operated off-site maintained by a VoIP provider and the Virtual PBX is operated in the cloud.

PABX: a PABX uses traditional PSTN landlines to make and connect calls both internally and externally. It is an “on-premise” system and since it has been the first kind of PBX, many businesses still have these legacy systems in place. But the PSTN technology tends to be outdated and costly so less and less organization invest in such a PBX

IPBX: from the name you probably already guessed what is an IPBX, but for those who just picked up the reading and IPBX is an IP-based PBX system that handles calls traffic within the organization endpoints (IP phones for instance) and connect those endpoints to the outside voice world. it’s much more cost-effective than a PABX and it offers much more flexibility and features. Indeed since it is an IP-based system it enables not only to carry VOIP with advanced call routing scenario but it can also integrate video conferencing solutions, Instant Messaging, contact.

Hosted PBX/Centrex: if you want to benefit from all the features of an IPBX without having it in your building you probably want to go for a hosted solution. The organization is interconnected with the voice service provider with a SIP trunk and this is the provider host the IPBX within its infrastructure. The voice services provider manage, update, maintain the IPBX, and the organization benefits from all the routing scenarios and services remotely. It’s one of the fastest-growing solutions.

Cloud PBX: Cloud PBX solutions are very similar and even sometimes indistinguishable from hosted PBX. The main difference is that Cloud PBX can be hosted on public cloud solutions, not only in the voice service provider servers, the solution can be shared among several clients and it is therefore usually more standardized with customization options. Saas company providing cloud telephony solutions are the perfect example of a cloud PBX provider. Organizations order lines and use the Cloud PBX services from their computer, IP phones, or app without the need of set-upping their phone system themselves.

Origination: Call origination or voice origination, refers to the collecting of the calls initiated by a calling party on a telephone exchange and handing off the calls to another endpoint (or callee). It is from the point of view of the caller. When you dial a number your voice operator see that you originate the call (your service provider then collect it and supposedly terminate this call somewhere else)

Collection: Collection is like the origination but form the point of view of the voice operator. The voice operator collects a call the caller originates.

Termination: We grant you that this term can seem a little barbaric but it just refers to the routing of a call to the callee. When a voice service operator offers you to carry your calls to their destination, it offers you a termination service. From you to the world.

VNO: A virtual network operator (VNO) is an entity that does not fully own a telecommunication infrastructure but provides managed telecom services and/or resell network services from other telecommunications suppliers. It doesn’t mean that the VNO doesn’t own any technical infrastructure most of the VNO own their core network infrastructure where all the intelligence lies and where the value of the service is created. It does mean though that they don’t own most of the hardware, like copper cables, optic fiber networks, mobile towers, or even physical servers. it can seem like a disadvantage but this is debatable. Indeed since you do not own the hardware you have to rent it and therefore you are less in control of it but the good thing is that you can have different providers, with different services, different prices, extend or scale more easily with a greater technical redundancy or security. So you will find strong defenders on both sides, but at Cantoo we are proudly a VNO because we like choice, redundancy, and security as much as we prefer to invest in improving our client’s service rather than owning the fiber cables.

MVNO: A Mobile virtual network operator (MVNO) is an entity that does not fully own a mobile telecommunication infrastructure. There are different levels of MVNO. from the light MVNO to the full MVNO. The light MVNO manages none of the mobile network, the mobile core network, or the mobile communication flows. It focuses on selling mobile plans and focus on managing the customer relationship. The full MVNO on the other hand manages everything but the physical mobile network (The mobile towers). It has a mobile core network and routes its SMS, Voice, and data flows itself and it also sells plans and manages the clients. In between you have different levels of independence from the hosting mobile network operator (MNO) and some MVNO can deal with the voice flow or with the data flow only, it depends on the contract between the parties and the level of technical know-how.

VNA/E: A virtual network aggregator (VNA) is a virtual network operator who resell its VNO services on a white-label basis to other market players. A virtual network enabler (VNE) is a VNO that leases its VNO technical platform and enable technically other operators to become a VNO. At Cantoo we are a VNA.

OBR/A-number Pricing: Origine based routing (OBR) or A-number pricing mechanism both refer to the capability of a voice provider to bill differently the calls depending on the destination, obviously, but also on the call origin, i-e the country/area of origin of the caller phone number. For instance, in France, it cost more to terminate a call from an Argentinian number to a French mobile phone than a Call from a german phone number. Some operators bill their clients the same price whatever the origin is and it results in very expensive rates for the client. We have made an article about the origin of the OBR and the opportunities it creates “What is the Origin Based Routing ? How to benefit from it?”. At Cantoo our platform is very good at billing exactly the right amount whatever the call origin and destination, making our client much more accurate and cheaper. We even offer to our clients to filter their traffic and terminate only some Origin/Destination pairs traffic.

AtoZ: The AtoZ price list refers to the full pricing list of an operator, listing all the destinations you can reach through this operator and all the prices per destination (and origins if the operator is OBR ready). It comes from the fact that usually the list is sorted by alphabetical order and starts with pricing for termination toward Afghanistan and ends with Zimbabwe. From A to Z!

Voice service quality: If a voice operator wants to provide quality services, it has to measure and value the quality of the traffic it receives and sends. To value the quality of voice traffic there are several KPIs (Key performance indicators) that one can look at. those are largely accepted and measured within the industry. Without being exhaustive, these KPIs allow you to make a first analysis of the service. Then to refine your analysis it is totally possible to create your own KPIs. The all-stars KPIs are the following: ACD, ASR, CAPS, NER, and Latency. Every operator should closely measure them.

ACD: ACD, or “Average Call Duration” is a quality metric which details the average length of an answered call made over the network, here is how it is computed:

ACD = duration of all answered calls/number of answered

A retail traffic should have an ACD over 60 sec (that is usually the minimum it lasts when you call someone). For call center calls it goes below and when it is under 10sec is usually spam calls (or password call requests which is fine though), you don’t want to route such traffic, it is armful to the callee, and your client-provider relationship. At Cantoo, our traffic shield enables us to detect, track and block those spamming calls based on ACD measurement. So we have a good relationship with our providers and long term route stability.

ASR: ASR or Answer-Seizure Ratio, also called the call completion rate, is the percentage of the number of successfully connected calls to the number of attempted calls computed as such:

ASR % = (total number of answered calls / total number of calls) × 100

Same thing we track this KPI very carefully at Cantoo and we consider that a retail traffic ASR should be at least 60%, below this it is usually that the traffic is a bit spammy or something is wrong with your core network. It can also be that the caller does not dial correctly the phone numbers or that the list of phone numbers he/she has is outdated and that most of the phone numbers are disconnected. Nevertheless, all things considered, a low ASR should raise concerns on your side

NER: NER or “network effectiveness ratio” is the smarter little brother of the ASR as far as your network performance monitoring is concerned. For us, it is the best metric to describe network performance. It is like the ASR but it excludes user behavior and it represents the pure network performance better. It’s computed as follow :

NER = (answers + user busy + ring no answer + terminal rejects) / number of total call attempts (seizures)

Weirdly the ASR remains more widely used than the NER to value the quality of an operator service or network. To us, it should be the industry standard because it is much more suitable compared to the ASR, which includes user behavior and is not a pure network performance metric.

CAPS: CAPS is the KPI of the total number of call requests that can be made by a telecoms system or network each second. it is computed as follow

CAPS = Total number of attempted calls / 60

CAPS is a more accurate measure of call processing than the commonly used CPS or Calls Per Second because it includes the unsuccessful call attempts (calls rejected, wrong number, ill-formed phone number…). Usually, a limit of 5 CAPS is sufficient for a local operator with a consumer or corporate telephone service. Obviously, the need for more CAPS grows as your volume grows and your provider or partners should be able to extend your limit as your traffic increases. This said a high CAPS rate with a low volume is a clear indicator of spam calls traffic.

Latency: Latency is the time between an action at one end of the network and its completion at the other end. In telephony, it is expressed for example by the time between dialing the number and the start of the ringing sequence. It is the time needed to establish the call. Latency then affects the time needed to transport “packets”, i.e. information between two interlocutors, literally the transport of the words you say on the phone. If this time is too long, you hear a lag, and your interventions overlap. Obviously the lower the latency, the better. It is generally affected by the geographical distance between callers and the multiplication of network nodes that the call must pass through. The closer the callers are geographically and the fewer technical intermediaries there are, the lower the latency will be. Below 150 milliseconds it is not perceptible, beyond that it is problematic. This latency can vary during a call, it’s called “jitter” and you have to make sure that it remains low to have a smooth conversation.

DIDs: Direct inward dialing (DID), also called direct dial-in (DDI) in Europe and Oceania, is a number offered by telephone companies to subscribers so he/she can we reached on the network. Seems complicated? Fear not It’s just how a phone number is called in the industry. It is a generic technical term referring to all kinds of phone numbers (mobile, fixed, premium, toll-free…). When you talk about mobile phone numbers the term used is MSISDN (Mobile Station International Subscriber Directory Number… Yep all of that)

CPaaS: A Communication Platform as a service (CPaaS) solution is the reunion of a telecom infrastructure, telecom interconnections, an API platform, and web interfaces into one product. This allows developers to add real-time communication capabilities to their own applications without the need to set up infrastructure and backend interfaces. Usually, the services are sold via a self-service web platform and those are actionable with web and application languages making the bridge between web and telecom technologies. Those platforms have known an important growth in usage in the last several years because it enables developers and entrepreneurs to use telecom technologies much more easily than it use to be. With a few lines of codes, developers can enable voice calls, video chat, messaging, and trigger SMS from their application without having to worry about telecom expertise and technologies.

We are using this article as an internal training material so we will add more concepts and refine some definitions as the time pass. Feel free to give us your feedback other our definitions or request new ones!

European Telcos

Wie wäre es mit einem benutzerdefinierten Projekt?

Sprechen Sie mit unserem Verkaufsteam:

Sie haben eine Rechtsanforderung?

E-Mail an uns zu

In Verbindung bleiben