Cisco ENWLSD 300-425 key terms

A structured process of measuring or predicting RF coverage, signal strength, SNR, and interference at a location before or after deployment. It produces the data used to place APs, set power and channels, and validate that design requirements are met.

A software simulation that models coverage by applying a chosen AP model, mounting height, antenna pattern, and transmit power to a building drawing. It replaces physical measurement for initial planning but must be confirmed by an on-site survey.

An on-site survey performed with a single access point mounted on a temporary tripod and moved around the floor. It validates the predictive model and reveals actual attenuation, interference, and coverage without installing the full AP fleet.

A post-installation measurement confirming that the deployed network meets design criteria such as coverage, SNR, roaming behavior, and capacity. It documents pass/fail against the requirements gathered during the assessment phase.

The reduction in RF signal strength as it travels through distance or material. Walls, glass, concrete, and metal each add loss measured in dB, and this loss drives how many APs a floor plan actually needs.

The signal loss between two isotropic antennas in open space with no obstructions, increasing with distance and frequency. It is the baseline for link budget calculations before adding material attenuation for walls and floors.

The accounting of transmit power, antenna gain, cable loss, and path loss that determines whether a client and AP can close a reliable link at a given distance. It is used to size coverage cells and verify uplink and downlink balance.

Equivalent isotropically radiated power: the total power radiated by an antenna, computed as transmit power plus antenna gain minus cable loss. Regulatory domains cap EIRP, and controller configurations must respect those limits.

Signal-to-noise ratio, the difference in dB between the received signal and the noise floor. Higher values support denser modulation and coding; low SNR forces lower data rates and degrades capacity even when signal strength looks adequate.

The ambient RF energy present at a location with no desired signal, expressed in dBm. It rises with interference sources, thermal noise, and wide channels, and it directly sets the SNR a client can achieve.

Received signal strength indicator, a relative measurement of the power a radio hears from a transmitter. Clients report it in vendor-specific units, so it is useful for trend and roaming thresholds but not directly comparable across device vendors.

The use of a radio receiver to sweep frequency bands and identify interferers such as microwave ovens, cordless phones, Bluetooth, and rogue APs. It distinguishes non-Wi-Fi interference that a normal Wi-Fi scan cannot see.

Degradation caused by two or more radios transmitting on the same channel within range of each other. In dense designs it limits capacity more than coverage, and it is managed through channel planning and transmit power control.

Assigning the same channel to cells that are physically far enough apart that their signals do not meaningfully interfere. The required reuse distance depends on transmit power, antenna patterns, and the CCI tolerance of the highest data rates in use.

The documented assignment of channels and channel widths to each AP in a design. It accounts for regulatory allowed channels, adjacent-channel overlap, and high-density areas where narrow channels are preferred over 80 MHz bonding.

A country-specific ruleset defining allowed frequencies, maximum EIRP, channel widths, and outdoor restrictions. Cisco controllers enforce it through the country code, which must be set correctly or APs may fail to join or operate illegally.

An embedded controller function on supported Cisco access points that provides a lightweight management and control plane without a dedicated appliance. It suits small deployments and has scale and feature limits compared with a hardware or virtual controller.

Cisco's current wireless controller family, available as appliances, virtual machines, and embedded on some switches. It runs IOS-XE and organizes configuration into policy tags, site tags, and RF tags instead of the older flat WLAN-to-interface model.

A 9800 controller object that maps a WLAN profile to a policy profile, binding SSID settings to VLAN, QoS, and security behavior. It decouples the wireless service definition from where the APs are physically located.

A 9800 controller object that associates an AP to an AP join profile and a policy tag, defining how the AP joins and which WLANs it broadcasts. It replaces the older AP group concept for most designs.

A 9800 controller object that groups APs for RF management, holding RRM, DCA, and TPC settings. APs sharing an RF tag participate in the same radio resource calculations and channel and power decisions.

Control and Provisioning of Wireless Access Points: the protocol carrying control traffic in a DTLS tunnel and optional data traffic between AP and controller. Data can be centrally switched through the tunnel or locally switched at the AP.

An AP mode where the AP can switch client traffic locally onto a VLAN at its own switch port while still being managed by the controller. It enables WAN survivability through local authentication and local switching during outages.

A deployment option in which client data is bridged at the AP's wired port instead of being tunneled to the controller. It reduces controller bandwidth and latency and is common in branch designs with FlexConnect.

Dynamic Channel Assignment, an RRM function that monitors interference and noise per radio and reassigns channels to reduce co-channel interference. It runs on a schedule and can be tuned for sensitivity, avoidance of non-Wi-Fi noise, and channel width.

An RRM function that adjusts AP transmit power so cells provide adequate coverage without excessive overlap. The goal is enough power for roaming and SNR while limiting co-channel interference and sticky-client behavior.

Two controllers configured as an active and standby pair sharing a redundancy management IP, where the standby takes over AP and client sessions if the active fails. State synchronization keeps CAPWAP and client state current.

Stateful switchover, the mechanism by which a standby controller assumes the active role with synchronized AP and client state, so sessions survive a failover. It requires a direct link and matching software and configuration between peers.

A virtual address shared by an HA pair that APs and management tools use to reach whichever controller is active. It follows the active role during failover, so APs do not need reconfiguration.

A design where one standby controller can take over for any single failed controller among several active ones. It is cheaper than 1:1 pairing but requires enough capacity and a plan for AP and client rejoin after failure.

A set of controllers that share client and AP information so clients can roam across them while keeping the same IP address. Members exchange messages over mobility tunnels and must agree on group name and peer addresses.

The data path between controllers in a mobility group that carries client traffic to the anchor controller holding the client's original subnet. It preserves the client IP address across controllers and subnets.

The controller that owns the client's point of presence and IP subnet for the duration of the session, while the foreign controller serves the client over the air. Traffic is tunneled to the anchor to keep the address stable.

A dedicated controller, usually in a DMZ, that anchors guest client traffic so guest subnets never touch internal networks. Guest WLANs tunnel from internal foreign controllers to this anchor for centralized policy and firewall inspection.

A segmented network zone between the internet edge and internal networks that hosts externally reachable services under stricter firewall policy. Guest anchors and web authentication portals are commonly placed there to isolate untrusted traffic.

A guest access method where the client's HTTP or HTTPS session is redirected to a portal for credentials or acceptable-use acceptance before network access is granted. It can be local to the controller or use an external portal server.

The practice of carrying guest traffic from internal controllers to a dedicated guest anchor over a mobility tunnel, keeping guest VLANs and DHCP off internal switches. It centralizes egress and simplifies firewall rules.

A location technique that estimates a client's position from signal strength reports received by multiple APs, using trilateration or fingerprinting. Accuracy is limited by multipath and by how often clients transmit.

A Cisco high-accuracy location capability using an advanced antenna module and angle-of-arrival processing on APs to improve client positioning beyond standard RSSI methods. It requires specific AP hardware and calibration.

A positioning method that estimates direction to a transmitter from phase differences across multiple antenna elements. Combined with signal strength it improves accuracy in areas where multipath degrades simple distance estimates.

The controller and appliance functions that collect AP measurements and compute device positions for analytics, asset tracking, and policy. Designs must account for AP placement, height, and reporting intervals that affect accuracy.

Cisco Connected Mobile Experiences, a platform that consumes location data to provide presence analytics, heatmaps, and zone-based engagement. It depends on consistent AP placement and accurate controller location configuration.

Port-based network access control using EAP over LAN, where a supplicant authenticates to a RADIUS server through the authenticator before being authorized. In wireless, it can be done at the controller or locally at a FlexConnect AP.

An EAP method where both client and server authenticate with X.509 certificates, avoiding password-based credential theft. It requires a PKI to issue and manage client certificates and is common for high-security wireless designs.

The AAA protocol used to authenticate, authorize, and account for wireless users and devices. Designs must consider server redundancy, failover behavior, and whether authentication happens centrally or at the AP.

Public key infrastructure: the certificate authorities, enrollment processes, and revocation services that issue and validate certificates. Wireless designs use it for EAP-TLS client authentication and for controller and AP identity trust.

A FlexConnect feature that lets an AP authenticate clients against a local RADIUS server or cached credentials when the WAN link to the controller is down. It preserves branch access during outages at the cost of centralized policy.

The design pattern of tunneling guest SSIDs from internal controllers to a dedicated anchor in a DMZ, isolating guest traffic from internal VLANs. It centralizes guest egress and keeps guest subnets out of the campus core.

Client movement between APs joined to different controllers in the same mobility group. The client keeps its IP address because traffic is tunneled to the anchor controller, and the handoff must be fast enough for voice and video.

The signal level at which a client decides to look for a better AP, configured on the client side rather than the network. Network designs influence it indirectly through cell overlap and minimum data rate settings.

A 9800 controller object holding settings that govern how an AP connects and operates, such as CAPWAP timers, LED behavior, and statistics collection. It is referenced by a site tag and applied to APs at join.

A controller setting that lets APs learn their regulatory domain from the controller and adjust allowed channels and power accordingly. It is important for designs spanning countries with different RF regulations.