CNPE key terms

A LAN architecture that separates access, distribution, and core layers so each layer handles a distinct role, simplifying scaling, troubleshooting, and policy enforcement across the enterprise campus.

A two-tier design where distribution and core functions merge into one layer, typically chosen for smaller sites where dedicated core switches add cost and hop count without benefit.

A data center fabric where every leaf switch connects to every spine switch, giving predictable any-to-any latency and allowing equal-cost multipath forwarding instead of spanning tree blocking.

Advertising a single aggregate prefix that covers multiple more-specific subnets, which shrinks routing tables and limits the blast radius of topology changes to the summarizing boundary.

A vendor-assigned preference value used to rank routes to the same prefix learned from different sources, where a lower number wins before any metric comparison occurs.

A static route configured with an administrative distance higher than the primary routing source, so it stays inactive until the preferred path is withdrawn from the table.

A routing behavior that installs several next hops for the same prefix when metrics tie, letting the device load-share traffic across parallel links instead of choosing one path.

A lightweight hello-based protocol that detects path failure between two devices in milliseconds, often triggering faster reconvergence than routing protocol timers alone would provide.

The process by which routers detect a topology change, exchange updates, recompute best paths, and reach a consistent view of reachability across the routing domain.

The forwarding rule that a router selects the most specific matching route, so a /28 entry wins over a /24 covering the same destination address.

A technique that forwards packets based on configured match criteria such as source address or protocol rather than the destination-based routing table alone.

Bundling multiple physical links into one logical interface to increase bandwidth and provide redundancy, requiring matching configuration on both ends to avoid forwarding loops.

A Layer 2 control protocol that blocks redundant paths so a switched network forms a loop-free tree, reconverging when a link or bridge fails.

The message switches exchange to elect a root bridge, measure path cost, and agree on which ports forward or block under a spanning tree topology.

A technology that runs multiple independent routing tables on one device, letting overlapping address spaces coexist while keeping each tenant's traffic logically separated.

An encapsulation that carries Layer 2 frames inside UDP across a routed underlay, extending segments between sites or across a data center fabric without stretching spanning tree.

A security model that treats no network location as inherently trusted, verifying identity and device posture for every request and enforcing least-privilege access continuously.

Applying fine-grained security policy between individual workloads or endpoints rather than at a perimeter, often enforced by host agents or fabric policy engines.

An ordered set of permit and deny rules matched against packet fields, with an implicit deny at the end and counters used to verify whether traffic actually hits a rule.

A system that authenticates and profiles devices before admitting them to a network, then places endpoints into VLANs or roles matching their compliance state.

A port-based authentication standard using supplicant, authenticator, and authentication server roles, where the switch port stays restricted until credentials are accepted.

A framework of authentication methods used within 802.1X and remote access tunnels, with variants differing in whether they use certificates, passwords, or both.

A suite of protocols that authenticates and encrypts IP packets, commonly deployed in tunnel mode for site-to-site VPNs using IKE to negotiate security associations.

A wide-area architecture that centralizes policy and steers traffic across multiple transports such as broadband, MPLS, and LTE based on application requirements and link health.

A contract defining measurable performance and availability commitments, such as latency, jitter, and uptime, used to judge whether a provider or internal service meets expectations.

The average time needed to restore a failed component or service, a reliability metric that pairs with mean time between failures to estimate availability.

A structured investigation that moves past symptoms to identify the underlying technical or process failure, then documents corrective actions to prevent recurrence.

A recorded snapshot of normal utilization, latency, and error rates that lets engineers compare current behavior against known-good values when diagnosing degradation.

A protocol for polling device metrics and receiving traps, using a management information base to describe objects and often paired with flow or streaming telemetry.

A standard for sending event messages from network devices to a central collector, with severity levels that let operators filter noise from actionable alerts.

A protocol that synchronizes device clocks to a reference source, which is essential for correlating logs and validating certificates across many devices.

A set of protocols such as VRRP or HSRP that present a shared virtual gateway address so hosts keep connectivity when their default router fails.

Advertising the same address or prefix from multiple locations so routing delivers each client to the nearest instance, commonly used for DNS resolvers and content delivery.

The interdomain routing protocol that exchanges reachability between autonomous systems, selecting paths through attributes such as AS path length and local preference.

Managing network and compute configuration through version-controlled declarative files, enabling repeatable deployments, peer review, and rollback instead of manual changes.

The property that running an automation task repeatedly produces the same end state, so retries and reruns are safe without duplicating or compounding changes.

The gradual divergence between a device's actual running configuration and its intended or documented state, often caused by manual changes made outside automation.

An HTTP-based interface style using methods like GET and POST on resource URLs, widely used by network controllers for programmatic configuration and monitoring.

A data modeling language that defines the structure and constraints of configuration and state for network devices, used with protocols such as NETCONF and RESTCONF.

A platform that centralizes access point configuration, client authentication, and roaming decisions, deployed as an appliance or as a cloud-hosted service.

The process of a wireless client moving between access points while maintaining its session, which depends on coordinated key management and timely handoff decisions.

A site assessment that measures signal coverage, interference, and channel overlap, guiding access point placement and channel plans before or after deployment.