Cisco 300-625 DCSAN key terms

A logically isolated Fibre Channel fabric created inside one or more physical switches, with its own fabric services, domain ID space, and zoning database. Traffic from one VSAN never reaches another unless explicitly routed.

The process in which an N port logs in to the fabric and receives a fabric-assigned FC ID from the principal switch. Successful FLOGI confirms the port is connected to a working fabric and is required before name service registration.

A session setup between two N ports that exchanges service parameters before data transfer. It happens after FLOGI and establishes the login context used by SCSI I/O and other upper-layer protocols.

A three-byte Fibre Channel address assigned to an N port, written as domain, area, and port identifier. The domain portion must be unique within a fabric and is used for routing frames between switches.

The unique number identifying each switch within a fabric, forming the first byte of every FC ID it owns. Duplicate domain IDs prevent ISL formation, and static assignment is common in stable production fabrics.

The switch elected by the fabric to allocate domain IDs and coordinate fabric-wide services. Election is based on priority and then WWN, and a new election occurs when the principal switch or an ISL fails.

A link connecting two Fibre Channel switches, typically an E port on each end, used to carry frames between switches in the same fabric. ISLs must be in the same VSAN and carry merged fabric services.

An expansion port on a Cisco MDS switch that connects to another switch and operates as an ISL. E ports exchange fabric parameters and must agree on VSAN, MTU, and other settings before coming up.

A fabric port on a Cisco MDS switch that connects to a node such as a host bus adapter or storage array. It assigns the attached N port its FC ID and provides name service registration.

A node port on an endpoint device, such as an HBA or a storage target port, that logs in to the fabric. An N port does not forward frames for other devices and requires an F port or NP port to attach.

A trunking expansion port that carries multiple VSANs over a single ISL by tagging frames with VSAN identifiers. Trunking must be enabled on both ends, and allowed VSAN lists control which VSANs cross the link.

The capability that lets one ISL or PortChannel carry traffic for several VSANs simultaneously by adding a VSAN header to each frame. It reduces cabling and is configured with allowed VSAN lists on TE ports.

A fabric-wide access control mechanism that groups ports or WWNs into zones and zones into zonesets, so only members of the same zone can communicate. The active zoneset is enforced by every switch in the VSAN.

A named group of fabric members, identified by pWWN, fWWN, FC ID, or interface, that are permitted to communicate with each other. Devices in different zones of the same VSAN cannot exchange frames.

An ordered collection of zones that is activated or deactivated as a unit for one VSAN. Only one zoneset can be active per VSAN, and activation distributes the configuration to all switches in the fabric.

The process of propagating the active zoneset from the switch where it was activated to every other switch in the VSAN. Distribution uses the fabric services protocol and requires ISL connectivity and consistent VSAN membership.

The worldwide name of a specific N port on an endpoint device, used as a zoning member type. Zoning by pWWN follows a device when it moves to another switch port, which simplifies re-cabling.

The worldwide name of a switch port, used as a zoning member so that whatever device connects to that port inherits the zone membership. It is convenient for fixed cabling but less secure than pWWN zoning.

A unique 64-bit identifier burned into Fibre Channel devices and switch ports. Worldwide names identify nodes and ports in login, name service, zoning, and device alias configuration.

A fabric service that stores registrations of logged-in N ports, including their FC IDs and worldwide names, so other devices can discover them. It supports queries by attribute and is queried by tools such as fcs discovery.

The fabric-wide process of re-electing a principal switch and reassigning domain IDs after a topology change such as an ISL or switch failure. Disruptive reconfiguration can briefly interrupt traffic, so stable fabrics use controlled changes.

A bundle of up to multiple ISLs between two switches that is treated as one logical link for forwarding and failure recovery. Members must have matching speed, VSAN, and trunking settings, and load balancing uses source and destination FC IDs.

A feature that allows selective traffic between VSANs without merging their fabrics, using IVR zones and a transit VSAN. It is used for resource sharing across isolated fabrics while keeping zoning and fault domains separate.

A special zone that defines which devices in different VSANs may communicate through IVR. Membership is expressed with IVR-specific zone member types, and the zone is placed in an IVR zoneset for activation.

A switch mode in which the device does not run full fabric services and instead connects hosts to an upstream NPIV core switch. It reduces domain ID consumption and simplifies edge deployments.

N Port ID Virtualization, a standard that lets one physical F port log in many N ports, each with its own FC ID. It is required for virtual machines and NPV edge switches to appear as separate fabric devices.

The port on an NPV switch that connects upstream to a core switch and behaves as an N port while proxying logins. It carries the FLOGI for each downstream device and requires NPIV support on the core switch port.

Fibre Channel over Ethernet, which encapsulates Fibre Channel frames in Ethernet frames so that LAN and SAN traffic share a converged link. It requires lossless Ethernet behavior such as PFC and typically DCB exchange.

The FCoE Initialization Protocol, used to discover FCoE-capable peers, negotiate VLANs, and perform FLOGI on behalf of the ENode. FIP runs before data traffic and can be used to check end-to-end FCoE readiness.

An Ethernet node that originates FCoE traffic, such as a converged network adapter on a server. It performs FIP discovery and FLOGI to obtain an FC ID through the FCF.

An FCoE Forwarder, the Ethernet bridge or switch function that provides fabric services to ENodes and forwards FCoE frames to the Fibre Channel fabric. A Cisco MDS switch can act as an FCF.

Priority Flow Control, an Ethernet mechanism that pauses only a specified traffic class instead of the whole link. It is essential for FCoE because dropped frames would break Fibre Channel delivery guarantees.

Data Center Bridging Exchange, a protocol that negotiates and advertises converged network settings such as PFC and ETS between link peers. Mismatched DCBX settings are a common reason FCoE links fail to come up.

The dedicated VLAN that carries FCoE traffic between an ENode and an FCF. It must be configured consistently on servers and switches and is kept separate from ordinary data VLANs.

A human-readable name mapped to a pWWN or fWWN so that zoning and CLI commands can reference devices by meaningful labels. The alias database is distributed fabric-wide and simplifies zone maintenance.

A feature that sends alerts and inventory messages to a configured destination such as email, HTTP, or a smart call home server. It helps operations staff learn about hardware failures and licensing issues promptly.

Simple Network Management Protocol, used to poll and receive traps from Cisco MDS switches for monitoring and alerting. Cisco MDS supports SNMPv1, v2c, and v3 with MIBs for interfaces, fabric, and hardware.

A logging facility that sends switch event messages to local buffers or remote servers at configured severity levels. It is commonly used to record fabric changes, port flaps, and security events for later review.

Role-Based Access Control, the Cisco MDS scheme that assigns users roles such as network-admin, network-operator, or vsan-admin to limit commands and VSAN scope. It is configured with roles and users locally or through AAA servers.

Authentication, Authorization, and Accounting, the framework that validates user identity, controls permitted actions, and records activity. Cisco MDS supports local, RADIUS, and TACACS+ servers with fallback options.

A fabric binding feature that restricts which devices may log in to specified ports by comparing their WWNs against a configured database. It protects against unauthorized devices and helps enforce zoning intent.

A feature that shuts down or brings up configured ports in response to the state of monitored uplinks, such as ISLs or server links. It speeds failover in server and storage access designs.

A diagnostic capability that identifies ports whose buffers fill because attached devices cannot accept frames fast enough, causing fabric-wide congestion. It reports credit-stall conditions and is used with congestion control features.

A set of features that detect and mitigate fabric congestion by limiting traffic from slow-draining devices, including edge and core policies. It reduces the spread of head-of-line blocking across the fabric.

The flow-control unit in Fibre Channel that grants a sender permission to transmit one frame. Insufficient credits limit throughput, and credit loss or exhaustion is a common cause of performance problems.

Quality of Service on Cisco MDS, which classifies traffic by VSAN or zone and assigns it to priority queues with configured bandwidth and MTU. It is used to protect critical storage traffic during congestion.

A feature on supported Cisco MDS platforms that inspects SCSI and NVMe traffic to report flow-level performance, latency, and error metrics. It helps identify slow hosts, targets, and paths without external taps.

A monitored traffic pair between an initiator and a target that SAN Analytics tracks for I/O counts, latency, and errors. Flows are identified by FC ID pairs and can be exported to external collectors.