Cable Internet

Cable Internet is a form of broadband Internet access which uses cable television infrastructure to transmit data. Cable Internet cabling does not require traditional telephone line connections, but does require cable television connections and wiring to be in place. 

Confidentiality, Integrity and Availability

Confidentiality, integrity and availability (often referred to as CIA) are three principal properties that information security aims to protect. To maintain confidentiality is to ensure that data remains private – only the intended and authorised recipients, individuals, processes or devices, may read the data. To maintain integrity is to ensure that data has not been altered during transmission from origin to reception. Availability is the assurance of timely and reliable access to data services.

Convergence is the merging of separate networks, technologies, and environments into one collaborative multi-media network. A converged network is theoretically capable of handling the different elements and functionalities associated with each separate network, and enables a higher level of interactivity between them. This booklet will be dealing with the convergence of voice data and regular data on the same network.

Denial of Service

A denial of service (DoS) attack is an attempt at limiting or stopping legitimate users from accessing a specific computer system or resource. In the context of this booklet, DoS attacks will mainly be referring to the disruption of VoIP telephony.

DSL (Digital Subscriber Line)

Digital subscriber line (DSL) is a technology which allows for digital data transmission over the wires of a local telephone network – enabling broadband Internet access. A particular form, called ADSL (asymmetric digital subscriber line) enables faster data transmission over copper lines than conventional modem based technology. The distinguishing characteristic of ADSL compared with other forms of DSL is that the volume of data flow is greater in one direction than the other – thus it is called asymmetric. Generally download bandwidth is greater than upload bandwidth.

Hardened System

A hardened system is a computer server / terminal which has been configured in such a way that it is highly resilient to security risks. A hardened system would likely have a well configured and up-to-date version of operating system, be well patched and have appropriate security software installed. The way the system communicates with other systems would be configured with security and protection in mind.   

Interoperability is the ability of different systems and technologies to communicate and share information with one another.

IP (Internet Protocol)

The internet protocol (IP) is a data-oriented protocol for transmitting data across computer networks. IP is one of the fundamental technologies on which the Internet is built. IP provides a best effort delivery strategy which means that there are no guarantees about packet delivery, however reliability and delivery can be enhanced with a number of solutions.

IP Packets

IP packets are small blocks of data which are used to send information across an IP network. A packet is a container of both the configuration and transport information required to deliver the packet to the correct destination, and the actual information that the system / user / device is trying to communicate, i.e. the payload.

PBX (Private Branch eXchange)

The private automatic branch exchange (PABX) or private branch exchange (PBX) is a connection between a private business and the PSTN. The PBX handles calls between your organisation’s extensions as well as connections to the PSTN.

POTS (Plain old telephone service)

Plain old telephone service (POTS) is a term which describes the telephone service that remains the basic form of residential and small business service connection to the telephone network in most parts of the world.

A protocol is a standard method for implementing communication between two computer entities. Different protocols can exist to tackle the same basic issue however their success may be highly varied. In many cases, the protocols must be the same at each end of a connection for computers to communicate.

PSTN (Public switched telephone network)

The public switched telephone network (PSTN) is the infrastructure for the world’s public circuit-switched telephone networks. This network is now almost entirely digital and includes fixed (land line) telephones. The PSTN is able to deliver quality of service (QoS) guarantees meaning that downtime of the network is limited.

SIP and H.323

The Session Initiation Protocol (SIP) and H.323 are the two standard protocols that enable voice communication connections to occur. SIP is the newer of the two and was created specifically for IP multimedia technologies. H.323 is an earlier protocol and was conceptualised initially for PBX technologies.

A softphone is a software program that enables IP telephony calls on a computer device or workstation. A softphone can be used with a microphone and speakers, or with a softphone capable handset (such as a USB IP telephone). An example softphone is Skype.