Glossary
Networking
16 terms- ASN (Autonomous System Number)
- A unique number assigned by a Regional Internet Registry (RIR) that identifies a network or group of networks under a single administrative domain. ASNs are used in BGP routing to distinguish between different organisations on the internet. Inferno operates AS207841.
- Bandwidth
- The maximum rate at which data can be transferred across a network connection, typically measured in megabits per second (Mbps) or gigabits per second (Gbps). Bandwidth is often confused with speed - it represents capacity, not latency.
- BGP (Border Gateway Protocol)
- The routing protocol that governs how data is routed across the internet between autonomous systems. BGP allows networks to advertise which IP address ranges they can reach, and is the foundation of internet routing. Multi-homed BGP setups enable failover between multiple upstream providers.
- CDN (Content Delivery Network)
- A geographically distributed network of servers that cache and serve content closer to end users. CDNs reduce latency and bandwidth costs by serving requests from a node near the user rather than the origin server.
- DDoS (Distributed Denial of Service)
- An attack in which large volumes of traffic from many sources are directed at a target to overwhelm its infrastructure and make it unavailable. Network-level DDoS protection detects and scrubs malicious traffic before it reaches your infrastructure.
- Internet Exchange (IX)
- A physical facility where multiple networks interconnect and exchange traffic directly, rather than through a third-party transit provider. Key UK exchanges include LINX (London Internet Exchange) and LONAP. IX peering improves performance and reduces costs.
- IP Transit
- A service in which one network carries traffic on behalf of another network to reach the broader internet. IP transit providers (upstream carriers) connect your network to the global routing table in exchange for a fee, typically based on bandwidth consumed.
- IPv4 / IPv6
- The two versions of the Internet Protocol used to address devices on a network. IPv4 uses 32-bit addresses (e.g. 192.168.1.1) and is largely exhausted. IPv6 uses 128-bit addresses providing a vastly larger address space. Both are in active use today.
- Latency
- The time it takes for a packet of data to travel from its source to its destination and back, measured in milliseconds (ms). Lower latency is critical for real-time applications such as VoIP, video conferencing, and online trading.
- Leased Line
- A dedicated, symmetric, point-to-point data connection between two locations. Unlike broadband, a leased line is uncontended - the full bandwidth is reserved exclusively for one customer, providing consistent performance and guaranteed SLAs.
- LIR (Local Internet Registry)
- An organisation authorised by a Regional Internet Registry (RIR) to allocate IP addresses and ASNs to its members or customers. Inferno is a RIPE NCC member LIR and can sponsor and manage resource allocations on behalf of third parties.
- MPLS (Multiprotocol Label Switching)
- A high-performance routing technique that directs data along predetermined paths using short labels rather than long network addresses. MPLS is commonly used to build private WANs with predictable performance, traffic engineering, and quality of service.
- Peering
- A mutual arrangement between two networks to exchange traffic directly without cost, typically at an internet exchange. Peering improves performance for traffic between the two networks and reduces reliance on paid upstream transit.
- RIPE NCC
- Réseaux IP Européens Network Coordination Centre - the Regional Internet Registry (RIR) responsible for allocating IP addresses and ASNs in Europe, the Middle East, and parts of Central Asia. RIPE NCC membership is required to receive IP resources directly.
- SD-WAN (Software-Defined Wide Area Network)
- A network architecture that uses software to manage and optimise traffic across multiple WAN connections (e.g. leased lines, broadband, LTE). SD-WAN enables centralised policy control, intelligent path selection, and dynamic failover across sites.
- VLAN (Virtual Local Area Network)
- A logical subdivision of a physical network, allowing devices to be grouped as if on the same LAN regardless of physical location. VLANs improve security by isolating traffic and are commonly used to separate departments or services within a network.
Telephony
12 terms- CODEC
- A standard for encoding and decoding audio in VoIP systems. Common codecs include G.711 (high quality, high bandwidth) and G.729 (compressed, lower bandwidth). The choice of codec affects call quality and the amount of bandwidth required per call.
- DDI (Direct Dial-In)
- A telephone number that routes directly to a specific extension or user within a PBX, without requiring the caller to go through a receptionist. DDIs allow businesses to present individual numbers to clients while sharing a smaller pool of physical lines.
- Hosted PBX
- A cloud-based telephone system in which the PBX infrastructure is hosted and managed by a provider rather than on-premises. Users connect via IP phones or softphones, and calls are delivered over the internet. Hosted PBX removes the need for on-site hardware.
- ISDN (Integrated Services Digital Network)
- A legacy digital telephone network standard used to carry voice and data over traditional copper lines. ISDN (BRI and PRI) has been widely replaced by SIP trunking and VoIP solutions, and is being phased out across the UK.
- IVR (Interactive Voice Response)
- An automated telephony system that interacts with callers using pre-recorded messages and menu options, routing them to the appropriate team or resource. IVR is commonly used for call handling outside business hours or for high-volume inbound queues.
- PBX (Private Branch Exchange)
- A private telephone switching system used within a business to route calls between internal extensions and external lines. Modern PBX systems are IP-based (IP-PBX) and support VoIP, conferencing, voicemail, and integration with CRM or helpdesk platforms.
- PSTN (Public Switched Telephone Network)
- The global network of circuit-switched telephone lines, originally analogue but now largely digital. The PSTN underpins traditional landline telephony and is the network that SIP trunks and VoIP services ultimately interconnect with to reach non-VoIP numbers.
- QoS (Quality of Service)
- A set of techniques used to manage network traffic and ensure that high-priority data - such as VoIP or video conferencing - is delivered with minimal delay and packet loss. QoS is critical for maintaining call quality on shared or congested links.
- SIP (Session Initiation Protocol)
- The signalling protocol used to establish, manage, and terminate real-time communication sessions such as voice and video calls over IP networks. SIP is the foundation of modern VoIP telephony and replaces legacy ISDN and analogue signalling.
- SIP Trunk
- A virtual telephone line delivered over an internet connection using the SIP protocol. SIP trunks replace traditional ISDN or analogue lines, connecting a business PBX to the PSTN. They are more flexible, cheaper to scale, and easier to manage than physical lines.
- Softphone
- A software application that enables a computer, smartphone, or tablet to make and receive VoIP calls. Softphones replicate the functionality of a desk phone and typically connect to a SIP trunk or hosted PBX, enabling flexible remote and hybrid working.
- VoIP (Voice over IP)
- Technology that transmits voice communications as digital packets over an IP network (such as the internet or a private WAN) rather than traditional circuit-switched telephone lines. VoIP is the underlying technology behind SIP trunking and hosted telephony.
Infrastructure
8 terms- Cabinet / Rack
- A standardised enclosure used to house servers, networking equipment, and other hardware in a datacentre. Racks are measured in rack units (U), with a standard full-size cabinet holding 42U. Equipment is mounted on rails within the cabinet.
- Colocation (Colo)
- A service in which a customer houses their own servers and equipment in a third-party datacentre facility. The provider supplies the physical space, power, cooling, and connectivity, while the customer retains ownership and control of the hardware.
- Cross-Connect
- A direct physical cable connection between two parties within the same datacentre facility. Cross-connects are used to establish private, low-latency links between colocation customers, or to connect to internet exchanges and carriers present in the same building.
- PUE (Power Usage Effectiveness)
- A metric used to measure the energy efficiency of a datacentre. PUE is calculated by dividing total facility power by the power consumed by IT equipment. A PUE of 1.0 is perfect efficiency; modern facilities typically achieve 1.2–1.4.
- Power Redundancy (N+1 / 2N)
- The level of backup power infrastructure within a datacentre. N+1 means one additional component beyond the minimum required (e.g. a spare UPS). 2N means full duplication of all power systems, providing the highest level of resilience.
- Rack Unit (U)
- The standard unit of vertical measurement for equipment mounted in a datacentre rack. One rack unit (1U) is 1.75 inches (44.45 mm) tall. Servers and switches are typically 1U, 2U, or 4U in height.
- Remote Hands
- A datacentre service in which on-site staff perform physical tasks on behalf of a colocation customer - such as rebooting a server, seating a cable, or swapping a drive - without the customer needing to be present at the facility.
- UPS (Uninterruptible Power Supply)
- A battery-backed device that provides emergency power to equipment if the mains supply fails. In a datacentre, UPS units bridge the gap between a power outage and the activation of diesel generators, ensuring continuous operation.
General IT
6 terms- Failover
- The automatic switching of a system or service to a backup resource when a primary component fails. Failover mechanisms are designed to maintain continuity with minimal or no disruption, and are a key component of high-availability infrastructure design.
- Managed Service
- An IT service model in which a provider assumes ongoing responsibility for managing a defined set of services or systems on behalf of a customer. Managed services typically include monitoring, maintenance, support, and proactive management under a fixed contract.
- NOC (Network Operations Centre)
- A centralised facility from which a provider monitors and manages network infrastructure around the clock. NOC engineers respond to alerts, investigate faults, and coordinate remediation to maintain service availability and performance.
- Redundancy
- The duplication of critical system components or functions to increase reliability and eliminate single points of failure. Redundancy can apply to power supplies, network links, hardware, or entire sites, and is fundamental to high-availability architecture.
- SLA (Service Level Agreement)
- A formal contract between a provider and a customer that defines the expected level of service, including uptime guarantees, response times, and resolution targets. SLAs typically include remedies (such as service credits) if the agreed levels are not met.
- Uptime
- The percentage of time a system or service is operational and available. Uptime is commonly expressed as a percentage over a given period - for example, 99.9% uptime equates to approximately 8.7 hours of downtime per year.
Still have questions?
Talk to our technical team
Whether you need clarification on a service or want to discuss how these technologies apply to your infrastructure, we're happy to help.