Aruba Switching Professional key terms

A logical Layer 2 broadcast domain created by grouping switch ports or tagging frames, letting one physical switch carry several isolated networks that behave like separate switches.

A standard that inserts a four-byte tag into Ethernet frames so a single link can carry traffic for multiple VLANs, with each frame identifying which VLAN it belongs to.

A switch interface assigned to exactly one VLAN that sends untagged frames to attached devices such as PCs, printers, or access points.

On an 802.1Q trunk, the one VLAN whose frames travel untagged; mismatched native VLAN settings on the two ends can merge traffic unexpectedly.

A Layer 2 protocol that elects a root bridge and blocks redundant paths so switched networks stay loop-free while still providing backup links.

The single switch elected as the reference point of a spanning tree; all other switches compute their shortest path toward it and block ports that would create loops.

Bridge Protocol Data Unit, the frame spanning tree switches exchange to advertise bridge and port identifiers, elect the root bridge, and detect topology changes.

A spanning tree edge setting that moves an end-device port straight to forwarding, skipping listening and learning delays; it should not be used toward switches or hubs.

A protection feature that err-disables a PortFast port if it receives a BPDU, preventing an unauthorized switch from joining and disrupting the spanning tree.

Combining several physical links between two devices into one logical channel to increase bandwidth and provide redundancy, using protocols such as LACP to negotiate the bundle.

Link Aggregation Control Protocol, an IEEE standard that exchanges control frames so both ends agree on which physical links form an aggregated channel and which are on standby.

A manually configured forwarding entry that tells the router where to send traffic for a specific destination prefix, useful for small networks or as a simple default path.

The next-hop address a host or switch uses when the destination is outside its own subnet, typically the router interface on the local segment.

The set of known destination prefixes, next hops, and metrics a router consults to decide where to forward each packet it receives.

An open standard link-state routing protocol in which routers flood link information, build a shared topology map, and compute shortest paths using cost.

A grouping of OSPF routers that share link-state information internally while summarizing routes at boundaries, which limits flooding and speeds convergence.

A switch feature that inspects DHCP messages and only allows server replies on trusted ports, blocking rogue servers and building a binding table used by other protections.

A security feature that validates ARP packets against the DHCP snooping binding table, dropping forged replies that would otherwise poison hosts' ARP caches.

Address Resolution Protocol, which maps a known IPv4 address to a MAC address on the local segment so frames can be addressed to the correct hardware.

A port-based access control standard in which a supplicant authenticates through the switch to a RADIUS server before the port grants normal network access.

A server protocol that centralizes authentication, authorization, and accounting, letting switches and wireless controllers validate user or device credentials against one database.

The client-side software on an endpoint that responds to 802.1X requests by sending credentials to the authenticator so the port can be authorized.

A weaker access method that authorizes a device by its MAC address alone, often used for printers or legacy devices that cannot run 802.1X supplicant software.

A switch interface designated as safe for server-originated control traffic, such as DHCP offers or ARP replies, while untrusted ports have such traffic filtered.

A switch feature that limits how many MAC addresses a port may learn and can restrict them to specific values, responding to violations by dropping, alerting, or disabling the port.

The name a wireless network advertises so clients can discover and associate to it; it identifies a service set rather than a specific access point.

The MAC address identifying a specific basic service set, usually the radio interface of one access point on one channel and SSID.

The process of a wireless client moving its association from one access point to another while keeping its session, ideally with fast, seamless handoff.

A slice of radio spectrum used for a wireless transmission; overlapping channels on nearby access points cause interference, so non-overlapping plans are used.

Degradation that occurs when multiple access points or clients transmit on the same channel in the same area, forcing them to contend for airtime.

Received Signal Strength Indicator, a relative measure of how strongly a client hears an access point, used to judge coverage and roaming thresholds.

Signal-to-noise ratio, the difference between signal strength and background noise level; higher values mean cleaner reception and support faster data rates.

Power over Ethernet, which delivers DC power over the same twisted-pair cable as data, letting access points, phones, and cameras run without separate power supplies.

Link Layer Discovery Protocol, a vendor-neutral method for neighbors to advertise identity, port, and capability information, useful for topology and PoE planning.

Simple Network Management Protocol, used by a manager to poll or receive traps from network devices for status, counters, and fault notification.

An unsolicited message a device sends to a management station when a notable event occurs, such as a link going down or a threshold being crossed.

A standard for sending timestamped event messages from network devices to a central collector, where they can be stored, searched, and alerted on.

Network Time Protocol, which synchronizes clocks across devices so that logs, traps, and certificates carry consistent timestamps and remain trustworthy during investigations.

Maximum Transmission Unit, the largest payload a link can carry in one frame; mismatches or oversized packets can cause fragmentation or silent drops.