Aruba Architect Expert (Written) flashcards

32 cards. Read the term and the definition here. The deck at the top of this page is optional.

Three-tier design

Hierarchical campus model with access, distribution, and core layers; distribution aggregates access switches and applies policy, while core provides high-speed transport between distribution blocks.

Collapsed core

Design where core and distribution functions run on the same devices, reducing cost and hops; suitable for smaller campuses where scale does not justify separate core hardware.

Oversubscription ratio

Ratio of aggregate downstream capacity to upstream capacity; a 20:1 access ratio means 20 Gbps of edge capacity shares 1 Gbps of uplink.

Availability formula

Availability equals MTBF divided by MTBF plus MTTR; reducing mean time to repair or increasing mean time between failures raises the percentage.

RF design precedence

Wireless coverage and capacity planning (AP placement, channel plan, power) is completed before logical WLAN, VLAN, and controller configuration.

PoE standards

802.3af delivers 15.4 W, 802.3at (PoE+) 30 W, and 802.3bt (PoE++) up to 60 or 90 W at the power sourcing equipment.

2.4 GHz channel plan

Non-overlapping 20 MHz channels 1, 6, and 11 are used in North America; adjacent-channel overlap causes co-channel interference and reduced throughput.

Cell edge RSSI

A common design target of about -67 dBm at the coverage boundary supports voice and data; SNR of 25 dB or better enables higher modulation rates.

High-density WLAN design

Design driven by client count and per-client throughput rather than coverage area; uses band steering, minimum data rates, and smaller cells.

Spine-leaf topology

Data center fabric where each leaf connects to every spine and spines do not interconnect; east-west traffic traverses a predictable, low-latency path.

VXLAN overhead

VXLAN encapsulation adds 50 bytes per packet; underlay links typically need 9000-byte MTU to carry full-size inner frames without fragmentation.

EVPN control plane

BGP-based control plane for VXLAN overlays that distributes MAC and IP reachability, enabling multihoming and reducing flooding.

SD-WAN path selection

Policy-based routing across multiple WAN transports that steers applications per path based on measured latency, jitter, loss, and SLA thresholds.

MLAG/VSX

Technology that lets two switches appear as one logical device for dual-homed servers and links, avoiding spanning-tree blocking on server uplinks.

Zero Trust principles

Verify explicitly, apply least privilege, and assume breach; enforcement moves close to the workload rather than relying only on a perimeter firewall.

802.1X authentication

Port-based access control using a supplicant, authenticator, and RADIUS server; EAP-TLS uses certificates, PEAP uses credentials inside a TLS tunnel.

MAB fallback

MAC Authentication Bypass authenticates devices that cannot run an 802.1X supplicant by their MAC address against the RADIUS server.

RADIUS vs TACACS+

RADIUS handles network access authentication and authorization; TACACS+ handles device administration with separate authentication, authorization, and per-command accounting.

Dynamic segmentation

After authentication, the infrastructure assigns a role or group that determines VLAN and policy, so access follows identity rather than physical port.

REST status codes

HTTP responses: 2xx indicates success, 3xx redirection, 4xx client error such as bad request or unauthorized, and 5xx server error.

Idempotent automation

An operation is idempotent when repeating it produces the same end state; declarative desired-state tools are idempotent while imperative scripts may not be.

NETCONF and YANG

Model-driven configuration protocol using YANG data models over SSH; RESTCONF exposes the same models over HTTP methods.

Automation vs orchestration

Automation executes individual repeatable tasks; orchestration coordinates multiple automated tasks into an end-to-end workflow across devices.

CI/CD for network

Version-controlled changes pass linting and validation, then a lab test, staged rollout, and documented rollback before production deployment.

SNMP polling vs traps

Polling queries devices at intervals for state; traps are unsolicited event notifications pushed by the device when a condition occurs.

Syslog severity levels

Numerical levels 0 through 7, from emergency to debug; lower numbers are more severe and production logging commonly targets levels 4 to 6.

Voice SLA thresholds

Common targets are one-way latency under 150 ms, jitter under 30 ms, and packet loss under 1 percent for acceptable voice quality.

Flow telemetry

NetFlow, IPFIX, and sFlow export flow records for traffic analysis, capacity planning, and anomaly detection without full packet capture.

Client experience metrics

Wireless assurance measures onboarding time, DHCP and AAA success, roaming time, and retry rates rather than only AP uptime.

Migration sequencing

Assess current state, design target, pilot, phased cutover, then decommission; rollback criteria are defined before any cutover begins.

EOL/EOS planning

Vendor end-of-sale and end-of-support notices drive refresh timing; budget cycles often need 12 to 18 months of lead time.

Change management

Formal process with CAB approval, documented backout plan, maintenance window, and post-change verification before closing the change record.