Nokia NRS I key terms

The forwarding rule that makes a router choose the route whose network prefix has the most bits in common with the destination address, regardless of route preference values or metric.

A per-source preference value used to rank routes to the same prefix learned from different protocols, so a more trusted source wins before any metric comparison happens.

The forwarding database a router builds from its routing protocol processes, holding the best route per prefix plus the next hop and outgoing interface used to reach it.

The hardware- or linecard-level table derived from the routing table, holding resolved next-hop and encapsulation data so packets can be forwarded without consulting the control plane.

The IP address of the adjacent device to which a router hands a packet for a given destination prefix, together with the interface through which that neighbour is reachable.

The process of resolving a route's next hop by looking that next-hop address up in the routing table again, until an interface directly connected to the destination is found.

Importing routes learned by one routing protocol into another so the two domains can exchange reachability, typically requiring metric translation and loop-prevention controls such as tags or filters.

An ordered set of match-and-action statements applied to routes on import or export, used to filter prefixes, modify attributes, and set tags or local preference.

A logical grouping of OSPF-enabled interfaces that confines topology information and link-state flooding, with all non-backbone areas required to connect through area 0.

The OSPF or IS-IS packet unit that describes a router's local links and neighbours, flooded within an area so every router can build an identical topology database.

The router elected on a multi-access OSPF segment to originate the network link-state advertisement and to form adjacencies on behalf of all other routers on that segment.

A hierarchy in IS-IS where level 1 routers share intra-area topology and level 2 routers form the backbone, with level 1-2 routers leaking prefixes between the two.

The optional and well-known fields carried in BGP updates, such as AS path, local preference, MED, and next hop, which drive best-path selection between autonomous systems.

A set of IP networks and routers under a single administrative authority that presents a consistent routing policy to the outside world and is identified by a unique number.

A BGP speaker that receives routes from clients and re-advertises them to other clients, removing the need for a full mesh of internal BGP sessions inside an autonomous system.

A forwarding scheme in which a short fixed-length label pushed at ingress selects the outgoing path, so core routers switch on the label rather than re-examining the IP header.

The ordered sequence of label operations along which MPLS forwards a packet from ingress to egress, established either by a signalling protocol or by hop-by-hop label distribution.

The router at the boundary of an MPLS domain that pushes an incoming packet's first label or pops the final label before handing the packet back to plain IP forwarding.

A source-routing architecture in which the ingress node encodes a list of segments, such as node or adjacency identifiers, into the packet so transit nodes need no per-path state.

The address-like value that identifies a node or adjacency in segment routing; in SRv6 it is an IPv6 address, and in SR-MPLS it is encoded as an MPLS label.

The instantiation of segment routing over an MPLS data plane, where each segment identifier is represented as an MPLS label and stacked in the packet header.

In an EVPN multihoming context, the set of links on one customer site that attach to two or more provider edge nodes and are treated as a single logical attachment.

A BGP control-plane solution that distributes MAC and IP reachability plus multihoming information among provider edge nodes, enabling all-active multihoming and efficient layer-2 extension.

A tunnelling encapsulation that carries layer-2 frames inside UDP and IP, using a 24-bit virtual network identifier to separate many logical segments across a shared routed underlay.

The device that encapsulates frames into VXLAN at the source and decapsulates them at the destination, mapping the virtual network identifier to a local bridging or routing instance.

A data-centre topology in which every leaf switch connects to every spine switch, giving predictable, equal-cost paths between servers and easy horizontal scaling of bandwidth.

The capability to install several equally preferred next hops for one prefix and to spread traffic across them, usually hashed per flow to preserve packet ordering.

Several physical links bundled into one logical interface using a negotiation protocol such as LACP, providing added bandwidth and resilience if a member link fails.

Attaching a customer site or device to more than one upstream node or provider so that a single link or node failure does not isolate it, with active-standby or all-active operation.

Nokia's suite of applications for discovering, provisioning, and assuring IP and optical networks, combining service automation with model-driven device configuration and telemetry.

A data-modelling language that describes the configuration and state tree of a network device, forming the contract that automation tools and NETCONF or RESTCONF sessions operate against.

An XML-based protocol that edits, retrieves, and validates device configuration through YANG-modelled datastores over a secure transport session, supporting candidate and confirmed commit workflows.

A push mechanism in which a device streams YANG-modelled operational data to a collector on a subscription basis, replacing slow interval polling with near-real-time state.

An operating model where an operator declares the desired end state or service outcome and the platform computes and enforces the underlying device configuration and checks compliance.

A filter applied to traffic destined for the router's own CPU, rate-limiting or dropping packets so that floods and scans cannot exhaust control-plane resources.

An anti-spoofing check that drops a packet arriving on an interface if the routing table would not send traffic back to that source address out of the same interface.

An ordered list of permit and deny rules matched against packet fields such as source, destination, protocol, and port, applied at an interface or in a policy to filter traffic.

An IEEE layer-2 security standard that encrypts and authenticates Ethernet frames between directly connected devices, protecting links against eavesdropping and tampering.

A suite of protocols that authenticates and encrypts IP packets between peers, using security associations negotiated by IKE and applied through tunnel or transport mode.

A layered optical transport standard that adds forward error correction and management to wavelength-division multiplexing, providing switched and protected end-to-end optical paths.

Carrying many closely spaced optical channels on one fibre so a single pair can transport multiple independent high-capacity signals, each on its own wavelength.