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Telecom Acronyms & Glossary
of Terms

Our glossary covers common telecom acronyms and terms you’ll encounter in this industry. Navigate using the alphabet below, or scroll until something catches your eye – and if something isn’t covered here, please reach out to us and ask!

We know that telecom can feel like it has its own language, and with the rapid pace of technology, it takes effort to stay informed. Here at iTel, we’re ready to help.


ADSL – Asymmetric Digital Subscriber Line

High-speed internet connectivity over a traditional copper telephone line.

ATM – Asynchronous Transfer Mode

A telecommunications standard for digital transmission that integrates various kinds of traffic without requiring separate network overlays. It has been largely superseded by IP (Internet Protocol) technology but is still common in the public switched telephone network.


A word used to describe signal to noise ratio of a connection. The further away from the Central Office (C/O) the connection is, the greater the signal/noise ratio becomes, and the less throughput you receive. Learn More



aka, core network; the part of a computer network that interconnects networks, providing a path for the exchange of information between different LANs or subnetworks.


Abbreviated as a lower case ‘b’ – the basic unit of information in computing and digital communications. A bit is either a 0 or a 1.

BGP – Border Gateway Protocol

aka IP Advertising; responsible for looking at all of the available paths that data could travel and picking the best route, which usually means hopping between autonomous systems.


Abbreviated as an upper case ‘B’ – an octect (8) of 1’s and 0’s.


CRTC – Canadian Radio-Television & Telecommunications

A government organization dedicated to ensuring Canadians have access to world-class communications infrastructure by regulating the industry.

CES – Carrier Ethernet Services

Data communication services delivered to a subscriber by a service provider; speeds between 1Mbps and 100Gbps; differentiate traffic between different users; runs over various infrastructure and coexists with both L2 and L3 technology.

C/O – Central Office

Office in a locality to which subscriber home and business lines are connected on what is called a local loop often equipped with switching equipment to switch calls locally or long distance.

CPU – Central Processing Unit

A computer component that processes instructions to run operating systems/applications and receives user input, after which it produces output to be stored by the application or displayed to the user.

CoS – Class of Service

A term used in data and voice protocols to differentiate the types of payloads contained in the packet being transmitted.

COAX – Coaxial Cable

A type of electrical cable consisting of an inner conductor surrounded by a concentric conducting shield, with the two separated by a dielectric (insulating material) and a protective outer jacket; used to carry high-frequency signals with low losses.

Colo – Colocation

The practice of housing privately-owned servers and networking equipment in a third-party data centre.

CLEC – Competitive Local Exchange Carrier

A smaller telecommunication carrier that buys access to infrastructure from the ILEC’s.

Converged Voice

Combining data and voice services over one connection.

Cross Connect

Any connection between facilities provided as separate units by the data centre; usually between users and not necessarily between two servers owned by the same company.

CPE – Customer Premise Equipment

Any terminal or equipment located at a subscriber’s location and connected with a carrier’s telecommunication circuit.



Dark Fibre

Unused optical fibre; frequently refers to the potential network capacity of the infrastructure.

DDoS – Distributed Denial of Service

An attempt to disrupt the general traffic to a site by overloading the network with a flood of internet traffic. Learn More about iTel DDoS Protection

Demarc – Demarcation Point

The location where the service (copper/fibre) comes into the service building.

DHCP – Dynamic Host Configuration Protocol

A protocol to dynamically assign an IP address to network devices that require them. This protocol also automates, manages, and reconfigures IP addresses for devices as needed.

DSL – Digital Subscriber Line

A group of technology that works together to transmit data over telephone lines; more currently used in regards to Asymmetric Digital Subscriber Lines (ADSL) which is a widely used internet connection; can be internet and phone paired. Learn more about iTel DSL Internet

DIA – Direct Internet Access

Fully dedicated bandwidth with consistent speeds that connects a specific business or location to the internet.

DID – Direct Inward Dial

Phone service that allows for the immediate redirection to a phone number through a business line without the need for a menu or queue.

Dry Loop

Telephone line without a number attached and therefore no dial tone.


EoA – Ethernet over ADSL

Digital subscriber line running over a pair of twisted copper (phone lines).

EoC – Ethernet over COAX

Ethernet running over coaxial cable; similar to television cable.

EPL – Ethernet Private Line

Point-to-Point connectivity between a pair of dedicated User Network Interfaces (UNIs) and allows for increased Network Transparency.

EVC – Ethernet Virtual Connection

Association between two or more UNI that identifies a P2P or multipoint-to-multipoint path within the network.

EVPL – Ethernet Virtual Private Line

The ability to enable multiple Ethernet Virtual Connection (EVCs) per UNI to support Point-to-Multipoint connectivity; basically a one-to-many topology.



A backup operational mode in which the functions of a system component are assumed by a backup component when the primary system is unavailable.

FOTB – Fibre Optic Termination Box

A protective box that houses fibre optic cable terminations and distributes links onwards. Also called the FTB – Fibre Termination Box.

FTTB – Fibre To The Building

Type of fibre-optic cable installation where the fibre cable goes to a point on a shared property and the other cabling provides the connection to single homes, offices or other spaces.

FTTN – Fibre To The Node/Neighbourhood

Type of internet service delivers internet to customers within a certain geographical distance, often the size of a neighbourhood. The internet service is sent to a hub and is then sent to the customer through DSL or cable technology.

FD – Frame Delay

Type of internet service delivers internet to customers within a certain geographical distance, often the size of a neighbourhood. The internet service is sent to a hub and is then sent to the customer through DSL or cable technology.

FDR – Frame Delivery Ratio

Measurement of link quality and available bandwidth. 

FDV – Frame Delay Variation

Measurement of jitter, aka, the difference between delays of consecutive packets travelling the same direction.

FQDN – Fully-Qualified Domain Name

Also called an absolute or complete domain name, this refers to the URL components that specify the exact location of the domain.


GPON – Gigabit-capable Passive Optical Network

A point-to-multipoint infrastructure that disperses data signals through a splitter to several end users. Learn more about GPON vs P2P Fibre Internet


HPBX – Hosted PBX

PBX that is hosted on the providers’ servers as opposed to on-premise in the business location. The hosting provider also becomes responsible for the maintenance and management of this infrastructure.

 Learn more about iTel Hosted PBX


ILEC – Incumbent Local Exchange Carrier

The initial companies that built out and maintain the infrastructure in Canada. Example: Telus, SaskTel, MTS, Bell, Bell Aliant.

Inside Wire

The location where the service will be installed or where the customer’s equipment will be.

IoT – Internet of Things

A blanket term for physical devices that connect to a network in order to send and receive data.

IVR – Interactive Voice Response

An automated telephony system that interacts with callers, gathers information and routes calls to the appropriate recipients. Learn about IVR best practices


Process for telecom operators to handle calls for other operators thus allowing people who are using different networks to communicate with each other in both domestic and international scenarios.



Aka ‘unreliable latency.’ Frequent, sizeable increases and decreases in latency.



L1 – Layer 1

The “physical” layer of the OSI model; transports raw bits of data, actual electrical signals, rather than the logical data packets that other layers handle.

L2 – Layer 2

The “data-link” layer of the OSI model; transfers data between adjacent network nodes in a wide area network or between nodes on the same local area network.

L3 – Layer 3

The “network” layer of the OSI model; provides the functional and procedural means of transferring variable length data sequences from a source host on one network to a destination host on a different network, while maintaining the quality of service requested by the transport layer.

Learn more about the layers of the OSI model here

LAN – Local Area Network

A collection of devices connected together in one physical location, such as a building, office, or home.


The amount of time it takes data to transfer from one point to another. The minimum for clear voice communication is 80ms – and the less, the better. Learn More about Latency

LD – Long Distance

Aka, a trunk or toll call; telephone call made to a location outside a defined local calling area.

LoRaWAN – Long Range Wide Area Network

A networking protocol for wireless data transmission with low power requirements and extensive range. Ideal for battery-operated sensors and other IoT.

LTE – Long Term Evolution

A type of 4G that delivers the fastest mobile Internet experience. Learn More about iTel’s LTE Internet


MTTR – Mean Time to Repair

The average time it takes for your provider to recover from a product or system failure. This includes the full time of the outage—from the time the system or product fails to the time that it becomes fully operational again.

MAC – Media Access Control

A network data transfer policy that determines how data is transmitted between two computer terminals through a network cable.

MAN – Metropolitan Area Network

A network that interconnects users with computer resources in a geographic area or region larger than that covered by even a large local area network (LAN) but smaller than the area covered by a wide area network (WAN).

MPLS – Multi-Protocol Label Switching

A data forwarding technology that increases the speed and controls the flow of network traffic. With MPLS, data is directed through a path via labels instead of requiring complex lookups in a routing table at every stop. Learn More about iTel’s MPLS


NID – Network Interface Device

A device that serves as the demarcation point between the carrier loop and customer wiring.

NNI – Network-to-Network Interface

An interface that specifies signalling and management functions between two networks.



A building does not already have fibre available/installed.


A building that is already equipped with fibre.


PBX – Private Branch Exchange

A private telephone network that provides organizations with a variety of useful features internally (eg, extension dialling, caller queues) in addition to standard telephone functions. The network infrastructure for a PBX can be implemented and maintained on-premise or can be hosted by a service provider.

Peak Capacity

The highest number of concurrent calls used by a customer at one time.

Pilot/Ghost Number

The primary phone number for a company that is often associated with other numbers (extensions or fax lines).

PoP – Point of Peering

A place where many networks interconnect to exchange traffic on a peering basis. It allows a network to peer with many other networks but only incurs the expense of a connection to a single point.

PSTN – Public Switched Telephone Network

The combined global infrastructure and services for public telephone services, including a broad range of interconnected transmission types, switching centres, and the numbering plan that allows most phones around the world to dial each other.

P2P – Point to Point

A data link layer (layer 2) communication protocol between two routers directly without any host or any other networking in between.  Learn about P2p vs GPON fibre

PPPoE – Point to Point Protocol over Ethernet 

Combining P2P and the ethernet link layer protocol in order to allow users to connect with a network of hosts over a bridge or access concentrator.

PRI – Primary Rate Interface

A telecommunications interface standard used on an Integrated Services Digital Network (ISDN) for carrying multiple voice and data transmissions between the network and a user. Learn more about iTel PRI’s


QoS – Quality of Service

A set of technologies that work on a network to guarantee its ability to dependably run high-priority applications and traffic under limited network capacity. Learn more about QoS


RU – Rack Unit

1.75in; most frequently used as a measurement of the overall height of 19-inch and 23-inch rack frames, as well as the height of equipment that mounts in these frames, whereby the height of the frame or equipment is expressed as multiples of rack units. For example, a typical full-size rack cage is 42U high, while equipment is typically 1U, 2U, 3U, or 4U high


SASE – Secure Access Service Edge

A network service delivery model that unites security, SD-WAN, cloud on-ramps, and more in a single, virtualized, streamlined service.

SBC – Session Border Controller

A network element that provides security and compatibility for Voice Over Internet Protocol (VoIP) at interconnection points between users and service providers. 

SD-WAN – Software-Defined Wide Area Networking

A virtual WAN architecture that allows enterprises to leverage any combination of transport services – including MPLS, LTE and broadband internet services – to securely connect users to applications. Learn more about iTel SD-WAN

SIP – Session Initiation Protocol

A signalling protocol that enables the Voice Over Internet Protocol (VoIP) by defining the messages sent between endpoints and managing the actual elements of a call. Learn more about iTel SIP Trunking

SLA – Service Level Agreement

An agreement that defines the level of service expected by a customer from a supplier, laying out the metrics by which that service is measured, and the remedies or penalties, if any, should the agreed-on service levels not be achieved. 

SMTP – Simple Mail Transfer Protocol

An internet standard protocol used by mail servers for sending and receiving mail messages. 

Static IP

An Internet Protocol (IP) address that doesn’t change. Once your device is assigned a static IP address, that number typically stays the same until the device is decommissioned or your network architecture changes.



TDM – Time Division Multiplexing

A method of transmitting and receiving independent signals over a common signal path by means of synchronized switches at each end of the transmission line so that each signal appears on the line only a fraction of time in an alternating pattern.


UCaaS – Unified Communications as a Service

A cloud-delivered unified communications model that supports six communications functions: Enterprise telephony. Meetings (audio/video/web conferencing) Unified messaging. Instant messaging and presence (personal and team). Learn more about iTel’s UCaaS options

UNI – User Network Interface

A demarcation point between the responsibility of the service provider and the responsibility of the subscriber. This is distinct from a network-to-network interface (NNI) that defines a similar interface between provider networks


VM – Virtual Machines

Compute resource that uses software instead of a physical computer to run programs and deploy apps.

VPN – Virtual Private Network

A networking solution that allows you to create a secure connection to another network over the Internet. VPNs can be used to access region-restricted websites, shield your browsing activity from prying eyes on public Wi-Fi, and more.

VoIP – Voice over IP

A protocol that allows you to create a secure connection to another network over the Internet. VPNs can be used to access region-restricted websites, shield your browsing activity from prying eyes on public Wi-Fi, and more.



Giving someone access to a single wavelength of light within a glass tube fibre. Learn more about iTel Wavelength Services.

Wet Loop

A regular phone line for voice calls/faxes; has dial tone.

WAN – Wide Area Network

A telecommunications network that extends over a large geographic area for the primary purpose of computer networking. Wide area networks are often established with leased telecommunication circuits.


Zero Trust

Refers to the Zero Trust Security Model, also called Zero Trust Architecture (ZTA) or Zero Trust Network Access (ZTNA). In this approach, IT systems are designed with ongoing verification and authentication as the default. This ensures a high standard of security is maintained.