> ## 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. |


This documentation is built and hosted on [Mintlify](https://mintlify.com), a developer documentation platform.