Glossary of terms


Asymmetric digital subscriber line (ADSL)

ADSL is a tail access/last mile connectivity broadband DSL technology where the upstream and downstream bandwidth is assigned different amounts of bandwidth. Downstream refers to data which you are downloading across the network to your local systems and LAN (such as Internet browsing and receiving email). Upstream refers to data you are sending from your local systems across the network (such as sending emails, applications and uploading files).

Autonomous system (AS)

An AS consists of a group of connected Internet protocol routing prefixes which are controlled by one or more network operators. This system is a network that has different policies than the networks or service providers to which it is connected. For an AS to be accepted as an autonomous system, it must have a single and clearly defined routing policy.



Backhaul refers to transporting traffic between distributed sites (typically PSTN telephone exchanges and aggregation points) and GCOMM’s centralised points of presence. GCOMM’s backhaul consists of a redundant ATM and Ethernet switching technologies

Border gateway protocol (BGP)

Border Gateway Protocol is the protocol which is used to make core routing decisions on the Internet. It does not involve traditional Internet Gateway Protocol (IPG) metrics. Instead, routing decisions are made based on path, network policies and/or rule-sets.


Centralised Internet gateway

A centralised Internet gateway is a single secure point on the network that allows an organisation’s multiple office locations to access the Internet using only a single firewall and a shared external IP address. This single gateway means that businesses can manage security policies more simply, while enforcing all external communication through a single secure point.  It also provides the highest possible access speed and redundancy to the Internet by not being dependant on a last mile tail.


Dark Fibre

Dark Fibre, also called unlit fibre, is a term that describes fibre optic cables that are already in the ground, but have not been allocated for use. The word “dark” refers to the fact that no light pulses are being sent through the cable, or in other words, the cables are not being used. There is no carrier equipment attached to Dark Fibre and it is ultimately the customer’s responsibility to purchase and install equipment on these cables.

Digital subscriber line (DSL)

DSL is a tail access/last mile connectivity technology for bringing high-bandwidth Internet connectivity to businesses over ordinary copper telephone (PSTN) lines. DSL shares the same phone line as the telephone service, however it uses a different part of the phone line’s bandwidth to provide an Internet or IP data network connection.



E1 (leased line) is a 2Mbps unframed service. It is delivered on 2 copper pairs (4 wires) as Ethernet. The distance does not affect performance, as is the case with DSL. However, the monthly service fees are calculated on a distance basis. E1 is a point to point service and has an A End and B End Termination (i.e. two addresses are required to provision the service).


File level backup

File level backup is a process that allows users to back up files and folders of their choice, instead of all the data residing on their computer. Users can perform file level backup manually or by using a software that can be set to automatically identify and backup files that have been updated since the last backup. This type of backup enables a better degree of granularity and allows businesses to save on data storage costs.


Image based backup

Image based backup is a process that creates a copy of the computer’s entire hard drive and all the data associated with it. This type of backup takes a “snapshot” of everything that is on the computer and saves it in a single file, or image. The advantage of image based backup is that users don’t have to worry about forgetting to select certain files as the image captures all the data and information on the computer.

Intermediate distribution frame (IDF)

An IDF is a rack, or a distribution frame, that is used for managing and interconnecting the telecommunications cable between end user equipment and a main distribution frame (MDF). Buildings with multiple floors may have an IDF on each floor which routs the cables all the way down to the first floor where they connect to the MDF.

Internet Protocol (IP)

IP is the communication protocol used throughout the Internet and private networks for directing (routing) data. All traffic needs to have IP address information for the routers to steer it to the correct destination.

Internet Protocol Security (IPsec)

IPsec is a set of communications protocols for protecting data flows between a pair of hosts, a pair of security gateways or between a security gateway and a host by authenticating and/or encrypting each IP packet of a communication session.

Internet Protocol version 6 (IPv6)

IPv6 is the most recent version of the Internet Protocol, which is responsible for providing a system that identifies and locates computers on networks and routs traffic across the Internet. IPv6 was created to solve the problem of address depletion which IPv4 is not able to support. Whereas IPv4 uses 32-bit addresses, its successor IPv6 uses a 128-bit address, allowing a far greater number of addresses.


Last mile tails

Last mile tails describe the technologies and processes used to connect the end customer to the GCOMM network. It refers to the final leg of the telecommunications networks delivering communications connectivity to the physical business location – the part that actually reaches the customer.

Layer 2

Layer 2 refers to the data link layer of the commonly referenced multilayered communication model, Open Systems Interconnection (OSI). The data link layer is concerned with moving data across the physical links in the network. In a network, the switch is a device that redirects data messages at the Layer 2 level, using the destination Media Access Control (MAC) address to determine where to direct network traffic. This is different than a Layer 3 network that uses IP addresses to determine where to direct network traffic.


Main distribution frame (MDF)

An MDF is often found at the local exchange or in an end customer’s building that is used to terminate the copper cables running from the end customer’s site. The frame allows these cables to be cross connected to other equipment such as a concentrator, a switch or a PBX.


Multihoming is a technique used to increase the reliability of the Internet connection for an IP network. Multiple connections, known as multihoming, reduce the chance of a potentially catastrophic shutdown if one of the connections should fail. In addition to maintaining a reliable connection, multihoming allows a company to perform load-balancing by lowering the number of computers connecting to the Internet through any single connection.

Multi Protocol Label Switching (MPLS)

MPLS is a language protocol scheme typically used to enhance an IP network. Routers on the incoming edge of the MPLS network add an ‘MPLS label’ to the top of each packet. This label is based on some criteria (e.g. destination IP address) and is then used to steer the packet through subsequent routers. Routers on the outgoing edge strip off the label before final delivery of the original packet. MPLS can be used for various benefits such as multiple types of traffic coexisting on the same network, integrating carrier networks, ease of traffic management, faster restoration after a failure, and, potentially, higher network performance.

MX record or Mail Exchanger

An MX record is a type of resource record in the Domain Name System (DNS) specifying how Internet e-mail should be routed. MX records point to the servers that should receive an e-mail, and their priority relative to each other.



Netview is GCOMM’s network performance monitoring software application that provides comprehensive bandwidth performance and fault management reporting. It allows customers and partners to view real-time statistics of their network directly from a web browser.

Network aggregation

Network aggregation refers to the combining of various networks (international, national, regional and local) in order to be able to provide the best ‘last mile’ technology, at the best cost at a particular location.

Network latency

Network latency refers to the time lapsed as data is transmitted from one point to another. Usually, the origin and destination points are used to determine the time delay. Network latency can be measured as either one-way or round-trip. With one-way, network latency is measured according to the time it takes for the data to travel from the source to the destination, whereas with round-trip the time from destination back to the source is also included in the measurement.

Network Operations Centre (NOC)

A NOC is a place from which network administrators supervise, monitor and maintain a telecommunications network. GCOMM’s NOC contains appropriate visibility over networks that are being monitored. GCOMM’s NOC is the focal point for network troubleshooting, software distribution and updating, router and domain name management, performance monitoring and coordination with affiliated networks. GCOMM’s NOC is currently located at the Gold Coast data centre.

Network termination unit (NTU)

A network termination unit or network termination equipment, as it is also referred to, is a device that connects the customer’s on-premise equipment to a carrier’s line that comes into the customer’s building.


Open pipe

An open pipe refers to the size of connection a network makes to the Internet. An open pipe is usually charged as a flat rate and allows the business to consume as much data upward or downward in a measured period of time. It is usually charged monthly and measured by the connection size. The greater the size commitment the cheaper the price would become. It is more suited to companies who want to fix their costs and are unsure of the quantity of traffic coming in and out of their network.

Open Shortest Path First (OSPF)

OSPF is a link state routing protocol for Internet Protocol (IP) networks. It uses a link state routing algorithm and belongs to the category of interior routing protocols operating within a single autonomous system (AS). This protocol uses the algorithm to determine the shortest connection path between the origin and destination points and directs data packets to travel on a route that is least congested with traffic.



Peering is an intentional, physical interconnection of separate Internet networks for the purpose of exchanging traffic between the users of each network. Through an agreement to exchange routing of information through the Border Gateway Protocol (BGP), two networks enter into what is called “peering”. There are two types of peering – public and private. Public peering happens when the interconnection between two networks is enabled through a multi-party shared switch fabric, such as an Ethernet switch. Private peering interconnections utilise a point-to-point link between the two networks to enable the exchange of traffic. Peering enables both parties to mutually benefit from things like reduced costs for transit services, increased redundancy, increased network capacity and improved performance.

Point of presence (PoP)

A point of presence is a physical location that houses servers, routers, switches and digital/analog call aggregators. GCOMM uses PoPs to connect to all of the national telecommunication carriers. Last mile tails are connected to the end customer’s business location and then back to the GCOMM PoPs.  GCOMM has multiple PoPs across Australia in partnership with some of the largest data centres in the nation.

Private branch exchange (PBX)

A private branch exchange, also called private automatic branch exchange (PABX), is a telephone exchange that is owned and operated by a private organisation, rather than by a carrier or telephone company. The function of the PBX is to switch calls on local lines between users within a company while allowing them to share one number of external phone lines, as well as to connect them to the PSTN via trunk lines. The major advantage and purpose of a PBX is to allow a company to save the cost of paying for an individual telephone line for each employee.

Public switched telephone network (PSTN)

A public switched telephone network is an aggregation of the world’s circuit-switched telephone networks, which are made up of telephone lines, fibre optic cables, cellular networks, underwater telephone cables, satellites and other links. These links communicate to each other via switching centres that are operated by national, regional or local telephony operators thus enabling any two telephones anywhere in the world to make calls to each other.


Quality of Service (QoS)

QoS is a term that incorporates packet loss, bandwidth, latency, and jitter to describe a network’s ability to customise the treatment of specific classes of traffic. For example, QoS can be used to prioritise different types of traffic such as voice, video, software applications and web traffic. GCOMM’s MPLS private IP network offers control over how traffic is classified.

QoS performs two functions on the private IP network: bandwidth allocation and time-sensitivity management. QoS allows the pre-allocation and reservation of bandwidth to critical applications or types of traffic and can further limit bandwidth availability for less critical applications.


Rack unit (RU)

An RU is a unit of measure used to describe the height of a server, network switch, router, firewall or other similar device mounted in a server or telecommunications rack. One rack unit is 44.45 mm (1.75 in) high.


Secure Sockets Layer Virtual Private Network (SSL VPN)

A virtual private network (VPN) enables secure exchange of data and other types of information transmitted between two endpoints. A secure sockets layer VPN is made up of one or more VPN devices to which the user connects via their web browser. SSL protocol is used to encrypt the traffic that travels between the web browser and the SSL VPN device, ensuring a secure communication. SSL VPN is used to provide remote users with access to web applications and internal network connections.

Service level agreement (SLA)

An SLA is a contract that exists between GCOMM and its customers. The SLA describes the common understanding about services, priorities, responsibilities, guarantees, etc. with the main purpose to agree on the level of service. GCOMM specifies the levels of availability, serviceability, performance, operation and other attributes of the service and even penalties that may apply in the case of a violation of the SLA.

Session Initiation Protocol (SIP)

SIP is a signaling communications protocol that is used for initiating and controlling interactive user sessions involving multimedia, such as video, voice, chat, gaming and virtual reality.

Simple Network Management Protocol (SNMP)

SNMP is a type of method used to manage computers and devices on IP networks, such as routers, switches, servers, printers, modems and other devices. It is used to monitor these devices and provide alerts if there are potential problems that need to be fixed. SNMP is the most commonly used mechanism for keeping an eye on the network and ensuring it is functioning the way it should be.

Switching technologies

A network switch is a computer networking device that channels incoming data from input ports to the specific output port that is supposed to take the data to its intended destination.


Telecommunication carrier interconnects

In telecommunications, interconnection is the physical linking of a carrier’s network with equipment or facilities not belonging to that network. The term may refer to a connection between a carrier’s facilities and the equipment belonging to its customer, or to a connection between two (or more) carriers.  GCOMM has carrier interconnects at each of our PoPs to Australia’s largest carrier networks.


Trunking is a method that enables a communications system, like a telephone network to provide access to many users by allowing them to share a set of lines or frequencies, instead of dedicating an individual line or trunk for each user. Trunking enables faster and more stable connectivity when there are multiple users in a system.


Virtual Local Area Network (VLAN)

VLANs are a method of creating independent logical networks within GCOMM’s physical network. A VLAN may consist of combining tail access/last mile connectivity services that behave as if connected to the same link layer network, even though they may actually be physically connected to different segments of GCOMM’s IP network (including interconnected carriers).

Voice over Internet Protocol (VoIP)

VoIP describes the ability to convert voice or fax calls into data packets for transmission over the Internet or private IP networks.