ACE Professional flashcards

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

Transit Gateway

A hub routing construct that connects many VPCs, VNets, and on-premises links through one attachment point, replacing full-mesh peering with centralized, policy-controlled routing.

VPC Peering Transitivity

Peering is strictly pairwise and non-transitive. If network A peers with B and B peers with C, A cannot reach C; a transit hub or direct peering is required.

Security Group Statefulness

Security groups track connection state, so reply traffic to an allowed outbound flow returns automatically. Network ACLs are stateless and need explicit rules for both directions.

Longest Prefix Match

A router selects the most specific matching route, so a /24 entry takes precedence over a /16 summary covering the same destination, regardless of other attributes.

Direct Interconnect

A dedicated private circuit between an enterprise site and a cloud provider, using BGP peering and bypassing the public internet for predictable latency and bandwidth.

Cloud Egress Charges

Fees billed per gigabyte for data leaving a cloud region or provider. Cross-zone and cross-region traffic is often billable, so workload placement affects cost.

BGP Local Preference

An autonomous-system-wide attribute used to choose the preferred outbound path. Higher values win, and it is exchanged among iBGP peers but not to external neighbors.

BGP AS Path Length

The count of autonomous systems a route traverses. Shorter paths are preferred after weight and local preference, and prepending can make a path less attractive.

iBGP Split Horizon

A route learned from one iBGP peer is not re-advertised to other iBGP peers, requiring a full mesh or route reflectors to distribute routes within an AS.

MED Attribute

Multi-Exit Discriminator hints to a neighboring AS which entry point to prefer. It is compared only among paths from the same neighbor AS by default.

Route Summarization

Advertising an aggregate prefix instead of many specifics. It shrinks routing tables and reduces churn but risks blackholing traffic when component prefixes fail.

BFD

Bidirectional Forwarding Detection sends rapid lightweight probes between routers to detect link or path failure in sub-second time, triggering faster BGP reconvergence.

Anycast Routing

The same prefix is advertised from multiple locations, and routing delivers users to the nearest instance. It underpins CDNs, DNS roots, and DDoS scrubbing.

RPKI Origin Validation

A signed record maps prefixes to authorized origin AS numbers. Routers mark announcements with mismatched origins as invalid, helping prevent prefix hijacking.

Administrative Distance

A ranking of route sources on a router. Lower values are trusted more: connected is 0, static 1, eBGP 20, and iBGP 200 by common defaults.

VXLAN VNI

A 24-bit identifier in VXLAN headers supporting roughly 16 million segments. Frames are encapsulated in UDP port 4789 across a routed underlay.

Wi-Fi 6E

An extension of 802.11ax into the 6 GHz band, adding many clean channels with less legacy interference, improving capacity and reliability in dense campus deployments.

WPA3 SAE

Simultaneous Authentication of Equals replaces the WPA2 PSK handshake with a password-authenticated key exchange, providing forward secrecy and resistance to offline dictionary attacks.

PoE Budget

The total power a switch can deliver to powered devices. It must cover the sum of AP, camera, and phone draw, with headroom for peak demand.

Group-Based Policy

Segmentation that enforces permitted communication based on identity or group tags rather than IP subnets, simplifying guest isolation and workload moves across the campus.

Rogue AP Containment

A wireless intrusion system compares detected BSSIDs to the authorized inventory and can send deauthentication frames to suppress unauthorized access points.

Campus Fabric Overlay

A virtual network built over a routed underlay using encapsulation such as VXLAN or LISP, providing segmentation and endpoint mobility independent of physical topology.

OFDMA

Orthogonal Frequency-Division Multiple Access, an 802.11ax feature that splits a channel into resource units so multiple clients transmit simultaneously, reducing contention in dense areas.

Streaming Telemetry

Model-driven, continuously pushed device data over gRPC or gNMI at sub-second intervals, giving far finer visibility than interval-based SNMP polling.

IPFIX Flow Records

Standardized per-conversation metadata including the five-tuple, byte and packet counts, timestamps, and optional application or autonomous-system fields for traffic analysis.

Synthetic Monitoring

Active probes injected from known vantage points to measure reachability, latency, and availability of services, independent of whether real users are present.

Four Golden Signals

Latency, traffic, errors, and saturation. These four measures summarize service and network health and guide which alerts and dashboards to build first.

Distributed Tracing

Requests carry trace and span identifiers across services, letting operators reconstruct end-to-end paths and pinpoint where latency or errors accumulate.

Metric Cardinality

The number of unique label combinations in a time series. High-cardinality dimensions such as user IDs or URLs inflate storage and query cost, so aggregate or sample them.

SLO and Error Budget

A service-level objective sets a target reliability level, and the error budget is the allowed shortfall. Budget consumption can gate releases and drive alert thresholds.

NTP Time Discipline

Accurate synchronized clocks across devices are required to correlate logs, flows, and metrics; drift misaligns timelines and breaks root-cause analysis.

sFlow Sampling

A packet-sampling flow technology that captures a statistical subset of traffic at an interface, exporting headers and counters with low device CPU overhead.

Symptom-Based Alerting

Alerts fire on user-visible failures such as elevated error rates or latency, rather than every underlying cause like a single interface flap, reducing alert noise.