CCNP Service Provider key terms

A source-routing architecture in which the ingress router encodes an ordered list of segments into the packet header, so core devices forward on that list instead of maintaining per-path state.

The instantiation of segment routing that carries segment lists as MPLS label stacks; each label represents a segment and is processed by existing MPLS forwarding hardware.

A 32-bit value that names a segment in SR-MPLS, encoded as an MPLS label; it may represent a node, an adjacency, or a service path instruction.

The Segment Routing Global Block is the range of local MPLS labels a router reserves for global segments; all nodes must use compatible ranges so prefix SIDs stay consistent.

A globally significant segment identifier assigned to a loopback prefix, so any node can steer traffic to that prefix by pushing the corresponding label.

A prefix SID advertised by multiple routers for the same address, letting traffic follow equal-cost paths to the nearest of those routers and providing inherent redundancy.

Topology-Independent Loop-Free Alternate computes a backup path using segment lists that avoids micro-loops after a failure, giving sub-50-millisecond protection without relying on topology shape.

BGP Labeled Unicast carries an MPLS label with each prefix advertisement, commonly used to distribute interior and inter-AS routes with labels in service provider cores.

A BGP speaker that receives routes from clients and reflects them to other clients, removing the need for a full iBGP mesh inside an autonomous system.

A method of splitting a large autonomous system into sub-ASes that run iBGP internally and eBGP-like sessions between sub-ASes, reducing full-mesh requirements while presenting one AS externally.

A set of routers under one administrative control that presents a single routing policy to the Internet, identified by a unique number assigned by a registry.

Multiprotocol Label Switching forwards packets using short fixed-length labels instead of destination lookups; the label stack allows tunneling, traffic engineering, and VPN separation.

The Label Distribution Protocol exchanges label bindings between adjacent routers for IGP-learned prefixes, building label-switched paths automatically without traffic-engineering constraints.

A Label Switched Path is the ordered sequence of routers and labels a packet traverses; it may be built by LDP, RSVP-TE, or segment routing.

The ordered set of MPLS labels on a packet; the top label drives forwarding at each hop while lower labels identify the VPN or service at the egress.

A behavior where the second-to-last router removes the top label before forwarding, so the egress router receives the packet with the service label already exposed.

An MPLS signaling protocol that reserves bandwidth and establishes explicitly routed label-switched paths, supporting traffic engineering and fast reroute through constraint-based path computation.

A protection mechanism that pre-computes and pre-installs a backup path so traffic is redirected locally within milliseconds of a link or node failure.

A service in which a provider carries customer IP routes over a shared MPLS backbone using VRFs and MP-BGP, isolating each customer's routing table from the others.

A Virtual Routing and Forwarding instance is a separate routing and forwarding table on a provider edge router, one per customer or service, keeping overlapping addresses independent.

An eight-byte value prepended to a customer prefix so that identical addresses from different VPNs become unique in MP-BGP; it does not control import or export.

A BGP extended community attached to VPN routes that determines which VRFs import them, effectively defining VPN membership and topology.

Multiprotocol BGP extends BGP with address-family identifiers so it can carry VPN routes, IPv6, and other families alongside traditional IPv4 unicast.

Virtual Private LAN Service offers multipoint Layer 2 connectivity across an MPLS network, making remote sites appear on one bridged Ethernet segment.

Ethernet VPN uses BGP control-plane signaling to advertise MAC and IP reachability for Layer 2 and Layer 3 services, replacing flood-and-learn with programmable, multipoint-aware signaling.

An emulated point-to-point circuit that carries a customer Layer 2 protocol across a packet-switched network, using control and encapsulation to preserve the original service.

A tunnel encapsulation that carries Layer 2 frames in UDP over an IP network, using a 24-bit virtual network identifier to scale tenant separation beyond VLAN limits.

A two-tier data center topology where every leaf connects to every spine, giving predictable latency and equal-cost multipathing; spines forward but do not host endpoints.

Equal-Cost Multipath spreads traffic across several equally preferred next hops, increasing bandwidth utilization and resilience without changing routing metrics.

A link-state interior gateway protocol that runs directly on Layer 2, scales well in large provider cores, and supports flexible TLVs used for traffic engineering and segment routing.

An interior gateway protocol that floods link-state advertisements to build a shortest-path tree; areas limit flooding scope and summarize routes at area boundaries.

A technique that stops advertising transit link addresses so only loopbacks and edge prefixes remain in the IGP, shrinking the topology database and improving convergence.

Quality of Service classifies, marks, queues, and polices traffic so latency-sensitive and business-critical flows get appropriate treatment during congestion.

Hierarchical QoS applies shaping and scheduling at two levels, such as per-subscriber and per-session, so providers can enforce both aggregate and individual service guarantees.

A traffic conditioner that meters a flow against a committed rate and drops or remarks excess packets, keeping traffic within contract without buffering.

A traffic conditioner that buffers excess packets and releases them at the contracted rate, smoothing bursts instead of dropping them as policing does.

A network management protocol that uses XML-encoded remote procedure calls over a secure transport to read and change device configuration in a structured, transactional way.

A data modeling language that defines the structure, constraints, and semantics of device configuration and state, enabling vendor-neutral automation and validation.

A gRPC-based protocol for retrieving, setting, and subscribing to device state using modeled paths, widely used for streaming telemetry and automation.

A push model in which devices stream structured operational data on a schedule or on change, replacing periodic polling with near-real-time, high-resolution monitoring.

Continuous delivery of device metrics and counters to a collector over a subscription, giving finer granularity and lower overhead than SNMP polling.

A legacy management protocol that polls MIB objects or receives traps, still common for basic fault monitoring but limited in scale and data granularity.