CCNP Enterprise key terms

A Cisco campus architecture that builds a fabric in which the control plane (LISP), data plane (VXLAN), and policy plane are separated, so wired, wireless, and IoT endpoints get consistent segmentation and policy wherever they connect.

A software-defined approach to the WAN in which a central controller programs branch routers to steer application traffic across MPLS, internet, and broadband links based on policy and measured link quality.

The physical routers, switches, and links that actually forward packets beneath an overlay. It only needs to provide IP reachability between tunnel endpoints; it does not itself enforce tenant separation.

A logical topology built with tunnels on top of a physical underlay. Encapsulation such as VXLAN or GRE hides the underlying hops so endpoints appear to sit on one flat segment.

Locator/ID Separation Protocol. It separates an endpoint's identity (the EID) from its current location (the RLOC) and uses map-server and map-resolver lookups so the fabric knows where each address lives.

Software that lets multiple virtual machines share one physical server by abstracting CPU, memory, storage, and network adapters. Type 1 runs directly on hardware; Type 2 runs on a host operating system.

A software switch inside a hypervisor that connects virtual machines' virtual NICs to each other and to physical uplinks, applying VLAN tags and security policy much like a hardware switch.

Virtual Extensible LAN. It encapsulates Layer 2 frames inside UDP/IP with a 24-bit VNI, supporting millions of segments and stretching them across a routed Layer 3 network.

Generic Routing Encapsulation. A lightweight tunneling protocol that wraps one protocol inside another IP packet, commonly used to carry multicast or non-IP traffic across a routed network without encryption.

Virtual Routing and Forwarding. It gives a single device multiple independent routing tables and forwarding instances, letting overlapping IP addresses coexist while keeping each tenant's or department's traffic isolated.

Open Shortest Path First. A link-state interior gateway protocol that floods link-state advertisements, builds a synchronized topology database per area, and runs the SPF algorithm to choose loop-free shortest paths.

Enhanced Interior Gateway Routing Protocol. A Cisco advanced distance-vector protocol that uses the DUAL algorithm, a composite metric, and bounded queries so it converges quickly while limiting routing updates.

Border Gateway Protocol. A path-vector exterior gateway protocol that exchanges reachability between autonomous systems and chooses best paths using attributes such as weight, LOCAL_PREF, AS_PATH, and MED.

Hot Standby Router Protocol. A Cisco first-hop redundancy protocol in which active and standby routers share a virtual IP and MAC address, so hosts keep a working default gateway when a router fails.

Bundling two or more physical links into one logical link so bandwidth aggregates and the loss of a member link does not break connectivity. LACP and PAgP negotiate the bundle.

A Layer 2 loop-prevention protocol that builds a loop-free tree and reconverges in seconds using proposal and agreement handshakes rather than the long timers of classic STP.

An IEEE standard that inserts a 12-bit VLAN identifier into Ethernet frames, letting one physical link between switches, routers, or access points carry traffic for many VLANs.

A device that centrally manages access points: pushing configuration, coordinating client roaming, enforcing policy, and often terminating CAPWAP tunnels for control and client data.

Control and Provisioning of Wireless Access Points. A protocol that builds a control tunnel, and optionally a data tunnel, between an access point and a wireless LAN controller across an IP network.

Network Address Translation rewrites IP addresses as packets cross a boundary; Port Address Translation also rewrites source ports, letting many internal hosts share one public address.

Simple Network Management Protocol. It lets a management station poll agents for device statistics and receive traps, using a MIB hierarchy to describe managed objects and their OIDs.

A logging standard that sends event messages from network devices to a collector, with each message carrying a facility and a severity level from 0 (emergency) through 7 (debugging).

A Cisco flow-export feature that summarizes traffic into flows keyed by source, destination, ports, and protocol, then exports records so you can see which hosts talk to which.

A feature that generates synthetic probes, such as ICMP echo or UDP jitter, between devices and measures reachability, latency, and loss so you can verify performance and trigger tracking actions.

Switched Port Analyzer. It copies traffic from selected ports or VLANs to a monitoring destination port so an analyzer can capture packets; ERSPAN extends this by tunneling copied traffic over IP.

Authentication, Authorization, and Accounting. A framework that verifies who a user is, what they may do, and logs what they did, usually by talking to a RADIUS or TACACS+ server.

An IEEE port-based access control standard. A supplicant authenticates through the switch or access point (the authenticator) to an authentication server before the port is opened.

Remote Authentication Dial-In User Service. An AAA protocol that combines authentication and authorization in one exchange and encrypts only the password, widely used for network access control such as 802.1X.

A Cisco AAA protocol that separates authentication, authorization, and accounting into distinct exchanges and encrypts the entire payload, typically used to control administrative access to network devices.

Access Control List. An ordered set of permit and deny rules matched against packet fields such as source, destination, protocol, and port, used to filter traffic or classify it for other features.

A Layer 2 switch feature that marks ports as trusted or untrusted and drops DHCP server messages arriving on untrusted ports, preventing rogue servers and building a binding table of legitimate clients.

A switch feature that validates ARP packets against the DHCP snooping binding table, discarding forged replies that would otherwise poison host ARP caches and enable man-in-the-middle attacks.

A Cisco policy architecture that tags packets with a Security Group Tag so enforcement points can apply group-based permissions without redesigning subnets or IP address ranges.

A network management protocol that runs over SSH, uses XML-encoded remote procedure calls, and edits device configuration datastores in a structured, transactional way.

A REST-style protocol that maps YANG-modeled data to HTTP methods and URLs, letting applications read and change device configuration and state using JSON or XML over HTTPS.

A data modeling language that defines the structure, types, and constraints of configuration and operational data, providing the schema that NETCONF and RESTCONF use to encode requests.

An interface that exposes resources at URLs and uses standard HTTP verbs such as GET, POST, PUT, and DELETE, usually exchanging JSON, so programs can interact with controllers and devices.

JavaScript Object Notation. A lightweight text format of key-value pairs, arrays, and nested objects that is widely used to encode data in REST API requests and responses.

An agentless automation tool that connects over SSH or APIs, runs playbooks written in YAML, and applies idempotent tasks to configure and validate many devices at once.