> ## Documentation Index > Fetch the complete documentation index at: https://docs.zayo.com/llms.txt > Use this file to discover all available pages before exploring further. # Terminology This glossary defines technical terms and acronyms related to networking. You may encounter some of these as you read through our documentation. | Term/Acronym | Definition | | ------------------- | --------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **ARP** | Address Resolution Protocol - A protocol that maps IP addresses to MAC addresses on a local network segment. | | **ASN** | Autonomous System Number - A unique identifier assigned to an autonomous system (a network under single administrative control) for BGP routing. | | **AWS** | Amazon Web Services - A cloud computing platform provided by Amazon. | | **Azure** | Microsoft Azure - A cloud computing platform provided by Microsoft. | | **BGP** | Border Gateway Protocol - A routing protocol used to exchange routing information between different networks on the internet. | | **BFD** | Bidirectional Forwarding Detection - A protocol that provides fast failure detection for network links and routing protocols. | | **CE-VLAN** | Customer Edge VLAN - A VLAN identifier used on the customer side of a network connection. | | **CIDR** | Classless Inter-Domain Routing - A method for allocating IP addresses and routing IP packets, represented with a slash notation (e.g., /30, /24). | | **Cloud Router** | A virtual routing and switching core that intelligently directs traffic between connected resources like data center ports, cloud links, and internet connections. | | **CPE** | Customer-Provided Equipment - Networking equipment owned and managed by the customer that interfaces with the service provider's network. | | **DDoS** | Distributed Denial of Service - A malicious attack that overwhelms a network or service with traffic from multiple sources, making it unavailable to legitimate users. | | **DIA** | Dedicated Internet Access - A dedicated, uncontended internet connection that provides exclusive access to allocated bandwidth with guaranteed performance. | | **DMZ** | Demilitarized Zone - A network segment that sits between an internal network and the internet, often used to host public-facing services. | | **DNS** | Domain Name System - A system that translates human-readable domain names (like example.com) into IP addresses. | | **E-Line** | Ethernet Line - A point-to-point Layer 2 connection that connects exactly two endpoints, providing transparent Layer 2 connectivity. | | **ELAN** | Ethernet LAN - A multi-point Layer 2 service that connects multiple endpoints in a single network segment, enabling any-to-any communication. | | **EVC** | Ethernet Virtual Circuit - A logical connection that carries Ethernet frames between two or more UNIs. | | **EVPL** | Ethernet Virtual Private Line - A point-to-multipoint service that supports multiple Ethernet Virtual Circuits per port using VLAN-based multiplexing. | | **EVPLAN** | Ethernet Virtual Private LAN - A service that allows customer CE-VLANs to establish discrete broadcast domains with service-multiplexing on UNIs. | | **FEC** | Forward Error Correction - A method of error control that adds redundant data to allow the receiver to detect and correct errors without retransmission. | | **Firewall** | A network security device that monitors and controls incoming and outgoing network traffic based on predetermined security rules. | | **FRR** | Fast Reroute - A technology that provides rapid recovery from network failures, typically in under 50 milliseconds. | | **GCP** | Google Cloud Platform - A cloud computing platform provided by Google. | | **GigE** | Gigabit Ethernet - A networking standard that supports data transfer rates of 1 gigabit per second. | | **HTTP** | Hypertext Transfer Protocol - The protocol used for transmitting web pages and other content over the internet. | | **HTTPS** | Hypertext Transfer Protocol Secure - A secure version of HTTP that uses encryption to protect data in transit. | | **ICMP** | Internet Control Message Protocol - A network protocol used to send error messages and operational information about network conditions. | | **IEEE** | Institute of Electrical and Electronics Engineers - An organization that develops technical standards, including many networking standards. | | **IETF** | Internet Engineering Task Force - An organization that develops and promotes internet standards. | | **IP** | Internet Protocol - The principal communications protocol for relaying datagrams across network boundaries. | | **IPAM** | IP Address Management - A system for planning, tracking, and managing IP address space in a network. | | **IPv4** | Internet Protocol version 4 - The fourth version of the Internet Protocol, using 32-bit addresses. | | **IPv6** | Internet Protocol version 6 - The most recent version of the Internet Protocol, using 128-bit addresses. | | **ISO** | International Organization for Standardization - An international standard-setting body. | | **ITU** | International Telecommunication Union - A United Nations agency that coordinates global telecommunications operations and services. | | **JSON** | JavaScript Object Notation - A lightweight data-interchange format used for transmitting data between systems. | | **L2** | Layer 2 - The Data Link layer of the OSI model, which uses MAC addresses to forward data frames within the same network segment. | | **L3** | Layer 3 - The Network layer of the OSI model, which uses IP addresses to route packets between different network segments. | | **LAN** | Local Area Network - A network that connects devices within a limited geographic area, such as an office or building. | | **Layer 2** | Data Link Layer - A networking layer that uses MAC addresses to forward data frames within the same network segment or VLAN. | | **Layer 3** | Network Layer - A networking layer that uses IP addresses to route packets between different network segments or subnets. | | **LOA/CFA** | Letter of Authorization/Cross-Connect Facility Assignment - Documentation that authorizes a service provider to establish a physical connection (cross-connect) at a data center or facility. | | **MAC** | Media Access Control - A unique identifier assigned to a network interface controller for use as a network address. | | **MEF** | Metro Ethernet Forum - An organization that develops technical specifications for carrier Ethernet services. | | **MMF** | Multi-Mode Fiber - Optical fiber designed to carry multiple light rays or modes simultaneously, typically used for shorter distances. | | **MPLS** | Multiprotocol Label Switching - A routing technique that directs data from one network node to the next based on short path labels rather than long network addresses. | | **MPOE** | Minimum Point of Entry - The point where a service provider's network enters a customer's building or facility. | | **MTU** | Maximum Transmission Unit - The largest size packet or frame that can be transmitted over a network without fragmentation. | | **NaaS** | Network as a Service - A cloud service model where networking capabilities are provided as a service over the internet. | | **NANOG** | North American Network Operators' Group - A forum for network operators to share technical information and best practices. | | **NAT** | Network Address Translation - A method of remapping one IP address space into another by modifying network address information in IP packet headers. | | **NID** | Network Interface Device - Equipment installed at a customer location to support network services, typically owned and maintained by the service provider. | | **NNI** | Network-to-Network Interface - The interface between two service provider networks. | | **OM** | Optical Multimode - A classification system for multimode fiber (OM1, OM2, OM3, OM4) that indicates fiber performance characteristics. | | **OSI** | Open Systems Interconnection - A conceptual model that characterizes and standardizes the communication functions of a network. | | **OSPF** | Open Shortest Path First - A routing protocol used to find the best path for packets as they pass through a set of connected networks. | | **PBR** | Policy-Based Routing - A routing technique that forwards traffic based on policies rather than the standard routing table. | | **PE** | Provider Edge - A router at the edge of a service provider's network that connects to customer networks. | | **PoP** | Point of Presence - A physical location where a service provider's network connects to the internet or other networks. | | **Port** | A physical connection point that acts as a bridge between an organization's internal network and the service provider's network infrastructure. | | **REST** | Representational State Transfer - An architectural style for designing web services that uses standard HTTP methods. | | **RJ45** | Registered Jack 45 - A standard type of physical connector used for Ethernet network cables. | | **SLAAC** | Stateless Address Autoconfiguration - A method for IPv6 hosts to automatically configure their IP addresses without a DHCP server. | | **SMF** | Single-Mode Fiber - Optical fiber designed to carry only a single ray of light, typically used for longer distances. | | **SNAT** | Source NAT - A type of Network Address Translation that translates the source IP address of outgoing packets, allowing multiple devices to share a single public IP address. | | **SNI** | Server Name Indication - An extension to the TLS protocol that allows a client to specify which hostname it is attempting to connect to. | | **SSH** | Secure Shell - A cryptographic network protocol for operating network services securely over an unsecured network. | | **TCP** | Transmission Control Protocol - A connection-oriented protocol that ensures reliable, ordered delivery of data between applications. | | **TGW** | Transit Gateway - A network transit hub that simplifies network architecture and reduces peering relationships. | | **UDP** | User Datagram Protocol - A connectionless protocol that provides a simple, unreliable datagram service. | | **UNI** | User Network Interface - The interface between a customer's network and the service provider's network. | | **VIF** | Virtual Interface - A logical interface that carries traffic over a physical connection, commonly used in cloud connectivity services. | | **VLAN** | Virtual Local Area Network - A logical network segment that groups devices together even if they are not on the same physical network switch. | | **VPC** | Virtual Private Cloud - An isolated virtual network within a public cloud environment. | | **Virtual Circuit** | A logical connection that enables traffic segmentation and connects various services and destinations over physical ports using VLANs. | | **WAN** | Wide Area Network - A network that spans a large geographic area, connecting multiple local area networks. | | **Web Filtering** | A service that provides granular control over web traffic by allowing you to define policies to block or permit access to specific URLs or categories of web content. |