Skip to main content
HSCN IP addressing good practice guidelines

Glossary of terms


A glossary of terms used throughout the HSCN IP addressing good practice guidelines.


ALG or Application Layer Gateway is a software component that manages specific application protocols such as SIP (Session Initiation Protocol) and FTP (File Transfer Protocol). An ALG acts an intermediary between the Internet and an application server that can understand the application protocol.

Anycast Address

The IETF RFC4291 - 'IP Version 6 Addressing Architecture' defines an Anycast Address as: "An identifier for a set of interfaces (typically belonging to different nodes). A packet sent to an anycast address is delivered to one of the interfaces identified by that address (the "nearest" one, according to the routing protocols' measure of distance)".


Border Gateway Protocol is a standardized exterior gateway protocol designed to exchange routing and reachability information among autonomous systems (AS) on the internet. The current version of BGP is version 4 (BGP4), which was published as RFC4271 in 2006 which updated the specification with common industry practices and includes support for Classless Inter-Domain Routing and use of route aggregation to decrease the size of routing tables.


The Bootstrap Protocol (BOOTP) is a computer networking protocol used in Internet Protocol networks to automatically assign an IP address to network devices from a configuration server.


Carrier Grade Network Address Translation (CGN) - a large-scale NAT that translates private IPv4 addresses into public IPv4 addresses. CGN employs Network Address and Port Translation methods to aggregate multiple private IPv4 addresses into fewer public IPv4 addresses. (Source: Cisco)


Classless Interdomain Routing - allows for the aggregation of different classes of IPv4 addresses. CIDR involves two portions of an IPv4 address, the network portion and the host portion. The network portion (the left-most bits) of a given IP address identifies a given network. The right-most bits are the host portion which identifies the host within a network. CIDR allows for the host portion of an IPv4 address to, in effect, borrow bits from the network portion, thus allowing for the conservation of address space, and allowing for more control within the local network.


CLAT handles the translation of IPv4 to IPv6 for applications that do not support DNS64. CLAT is needed when transitioning to IPv6 on Global System for Mobile Communications (GSM) networks using NAT64 as the IPv4 access method.


Customer premises equipment - associated equipment, generally a router (or modem, such as DSL), located at the customer or subscriber's premises and connected with a network provider or carrier's telecommunication channel at the demarcation point - that is, where the provider service connects to the customer network.


Dynamic Host Configuration Protocol (DHCP) is a network protocol that enables a server to automatically assign an IP address to a computer from a defined range of numbers (a scope) configured for a given network.


Domain Name System - The internet's system for converting alphabetic names into numeric IP addresses. For example, when a Web address (URL) is typed into a browser, DNS servers return the IP address of the Web server associated with that name.


Encapsulating Security Payload (ESP) is a member of the IPsec protocol suite. In IPsec it provides origin authenticity, integrity and confidentiality protection of packets. Defined in RFC4303.


File Transfer Protocol - a standard Internet protocol for transmitting files between computers over TCP/IP connections.


H.323 is a recommendation from the ITU Telecommunication Standardization Sector (ITU-T) that defines the protocols to provide audio-visual communication sessions on any packet network. H.323 is commonly used in VoIP, Internet Telephony, and IP-based videoconferencing.


Health and Social Care Network


Internet Engineering Task Force- a large open international community of network designers, operators, vendors, and researchers concerned with the evolution of the Internet architecture and Internet standards. IETF deals particularly with TCP/IP standards and the IP suite.


Internet Protocol Security (IPsec) is a protocol suite for secure Internet Protocol (IP) communications that works by authenticating and encrypting each IP packet of a communication.


Internet Protocol version 4 is the fourth revision of the Internet Protocol (IP).


Internet Protocol version 6 is the most recent version of the Internet Protocol (IP).


Internet service provider - a company that provides individuals and other companies with access to the internet and other related services such as web site building and virtual hosting.

MAC address

Media Access Control address - a hardware address that uniquely identifies each node of a network.

Multicast Address

The IETF RFC4291 - 'IP Version 6 Addressing Architecture' defines a Multicast Address as: "An identifier for a set of interfaces (typically belonging to different nodes). A packet sent to a multicast address is delivered to all interfaces identified by that address".


An MX record is an entry in a DNS table which controls where mail for a particular domain name is sent.


NHS National Network


Network address translation (NAT) is a method of remapping one IP address space into another by modifying network address information in Internet Protocol (IP) datagram packet headers while they are in transit across a traffic routing device.


NAT Traversal - a computer networking technique of establishing and maintaining Internet protocol connections across gateways that implement network address translation (NAT).


An operating system designed for computer networking to allow shared file and printer access among multiple computers in a network, enable the sharing of data, users, groups, security, applications, and other networking functions, typically over a LAN or private network.


Open Shortest Path First - a routing protocol for IP networks which uses a link state routing (LSR) algorithm and falls into the group of interior gateway protocols (IGPs), operating within a single autonomous system (AS). It is defined as OSPF Version 2 in RFC2328 (1998) for IPv4. Updates for IPv6 are specified as OSPF Version 3 in RFC5340 (2008).


Port Address Translation, also referred to as Network Address Port Translation, is a method by which many network addresses and their TCP/UDP ports are translated into a single network address and its TCP/UDP ports. See RFC3022 section 2.2.


A Request for Comments (RFC) is a formal document from the Internet Engineering Task Force (IETF) that is the result of committee drafting and subsequent review by interested parties.


The Réseaux IP Européens Network Coordination Centre (RIPE NCC) is the Regional Internet Registry (RIR) for Europe, the Middle East and parts of Central Asia.


Resource Reservation Protocol is used by a host to request specific qualities of service from the network for particular application data streams or flows. See RFC2205.


Simple Mail Transfer Protocol (SMTP) is an internet standard for electronic mail (email) transmission. First defined by RFC 821 in 1982, it was last updated in 2008 with the Extended SMTP additions by RFC 5321, which is the protocol in widespread use today.


Simple Network Management Protocol - a set of protocols for network management and monitoring supported by many typical network devices such as routers, hubs, bridges, switches, servers, workstations, printers, and other network components and devices.


Secure Sockets Layer - a standard security technology for establishing an encrypted link between a server and a client, typically a web server (website) and a browser, or a mail server and a mail client.


Transmission Control Protocol/Internet Protocol is the basic communication language or protocol of the Internet. It can also be used as a communications protocol in a private network. TCP and IP are two distinct computer network protocols but so commonly used together that TCP/IP has become standard terminology for referring to either or both of the protocols.


Transition Network - a backbone network service providing core network functionality; Points of Presence (PoPs); external Gateways; Access PoPs supporting Legacy N3 Access Services, Head End services; Broadband; Video Conferencing (VC); Virtual Private Network (VPN); IP Address Management (IPAM); Domain Name System (DNS); Network Time Protocol (NTP); Enhanced Internet Gateway (EIG); Enhanced Monitoring Service (EMS); Advanced Behavioural Analysis Suite (ABAS); Security Management Services; connectivity to the HSCN Peering Exchange Network; and Transitional Assistance to migrate TN end users from the legacy environment to the new HSCN environment.


User Datagram Protocol - part of the Internet Protocol suite. An alternative communications protocol to Transmission Control Protocol (TCP) used primarily for establishing low-latency and loss tolerating connections between applications. UDP is officially defined in RFC768.


A Uniform Resource Locator is a reference to a web resource that specifies its location on a computer network and a mechanism for retrieving it.


Virtual private network (VPN) - a private network that is built over a public infrastructure. Security mechanisms, such as encryption, allow VPN users to securely access a network from different locations via a public telecommunications network, most frequently the internet.

Last edited: 16 October 2018 12:37 pm