JNCDS-WAN key terms

Structured process of interviewing stakeholders to capture business goals, applications, traffic patterns, budget limits, and regulatory constraints before selecting technologies or producing a network design.

A table listing each source-to-destination pair in a network together with expected bandwidth, latency sensitivity, and direction, used to size links and place services.

A design situation where no existing network equipment or configuration must be preserved, allowing the designer to choose topology, protocols, and hardware without migration constraints.

A design situation where new equipment must interoperate with an installed network, so migration steps, legacy protocols, and outage windows shape the final architecture.

Spare link capacity, port density, and device resources reserved so a design can absorb growth without immediate hardware replacement or topology redesign.

A Junos SRX construct that groups interfaces sharing the same trust level; policies permit or deny traffic between zones rather than between individual interfaces.

A stateless Junos configuration applied to an interface or forwarding table that matches packet header fields and performs actions such as discard, accept, count, or log.

A set of standards that encrypts and authenticates IP packets between gateways, commonly used for site-to-site tunnels over untrusted WAN or internet links.

Unified threat management: a bundle of security features such as antivirus, antispam, intrusion prevention, and web filtering inspected in one policy on a security device.

An IEEE port-based access control standard where a supplicant authenticates to an authenticator before the switch grants normal VLAN access, often using RADIUS.

IEEE 802.1AE link-layer encryption that protects Ethernet frames hop by hop, useful for securing campus uplinks or WAN handoff segments against eavesdropping.

Juniper's centralized management application for discovering, configuring, monitoring, and upgrading Junos devices, with role-based access and workflow automation across the network.

Zero touch provisioning: a process where a new device boots, obtains an address, locates a controller or configuration server, and installs its intended configuration without manual CLI entry.

Bidirectional forwarding detection: a lightweight, rapid hello protocol that detects path failures between neighbors faster than routing protocol timers, triggering quicker convergence.

Nonstop active routing: Junos capability where the backup Routing Engine keeps routing protocol state synchronized so a mastership switch preserves forwarding and adjacencies.

In-service software upgrade: a procedure that upgrades Junos software with minimal traffic disruption by using redundant hardware or synchronized routing engines and graceful protocol handling.

Virtual Router Redundancy Protocol: multiple routers share a virtual IP and MAC, with one master forwarding traffic and a backup taking over if the master fails.

Multichassis link aggregation: two or more switches present one logical LAG to a server or access switch, providing link redundancy without spanning tree blocking.

A Layer 2 broadcast domain logically separated on switches, allowing groups of ports to share traffic while isolating them from other groups without separate physical hardware.

Rapid Spanning Tree Protocol: an IEEE loop-prevention protocol that builds a loop-free Layer 2 topology and converges faster than classic STP by using explicit port roles.

A Juniper feature that connects multiple EX Series switches into one logical device with a single management IP and shared configuration, simplifying campus access and distribution.

A Juniper architecture where one or more spine devices centrally manage many satellite switches, reducing per-device configuration and simplifying large campus or data center deployments.

Power over Ethernet: technology that delivers DC power and data over the same copper cable to devices such as access points, cameras, and IP phones, reducing cabling.

A provider-managed VPN service where MPLS labels and BGP route targets separate customer routing tables across a shared backbone, giving any-to-any IP connectivity.

Ethernet VPN: a BGP-based control plane that distributes MAC and IP reachability for Layer 2 and Layer 3 services, commonly paired with VXLAN encapsulation in data centers.

Software-defined WAN: centralized policy and control select paths across multiple WAN links, using application awareness and tunnels to optimize cost and performance.

A Juniper router product that makes forwarding decisions per session based on application and path quality, supporting software-defined WAN topologies without traditional tunnel overlays.

Class of service: a set of Junos mechanisms that classify traffic, queue it, and schedule transmission so latency-sensitive and business-critical applications receive preferred treatment during congestion.

Resource Reservation Protocol with Traffic Engineering: a signaling protocol that reserves bandwidth and establishes explicitly routed MPLS label-switched paths to meet service guarantees.

A data center underlay where every leaf and spine switch runs Layer 3 routing to every other switch, providing equal-cost multipath and avoiding spanning tree.

A two-tier data center topology where every leaf connects to every spine, keeping server-to-server paths short and predictable while scaling horizontally by adding leaves or spines.

Virtual Extensible LAN: an overlay encapsulation that places Layer 2 frames inside UDP/IP packets, extending segments across a routed underlay and scaling beyond VLAN limits.

A combined data center fabric design using EVPN as the BGP control plane and VXLAN as the data-plane overlay, enabling scalable Layer 2 and Layer 3 services over an IP underlay.

Juniper's data center and campus switching family, offering high-density 10/25/40/100/400 Gigabit Ethernet platforms used for spine, leaf, and border roles.

Juniper's SDN platform that provides centralized control and orchestration for overlay networks, multi-tenancy, and service chaining across data center and WAN domains.

A distributed gateway design where the same IP and MAC address are configured on every leaf, so a server's default gateway is always local regardless of rack.