Nokia NRS I flashcards

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

Longest-prefix match

A router forwards a packet to the route with the most specific prefix (largest subnet mask) among all matching routes; if multiple routes have the same prefix, preference/metric breaks the tie.

Nokia route preference

SR OS uses preference (administrative distance) to rank routes from different protocols; lower values are preferred. Defaults: direct 0, static 5, OSPF 10, IS-IS L2 18, BGP 170.

BGP best-path selection

SR OS selects BGP routes by: highest local-preference, shortest AS-path, lowest origin, lowest MED, eBGP over iBGP, lowest IGP cost to next hop, then lowest router ID.

OSPFv3 link-local next hop

OSPFv3 uses IPv6 link-local addresses (fe80::/10) as next hops, so the outgoing interface must be resolved; routes are installed with the interface, not a global next-hop address.

IS-IS wide metrics

IS-IS on SR OS supports wide metrics up to 2^24, enabling TE and large-scale topologies; narrow metrics are limited to 6 bits per link and are legacy.

Route redistribution policy

In SR OS, a route is redistributed into another protocol only if matched by an explicit policy statement with an accept action; otherwise it is silently dropped by the default policy.

ECMP on SR OS

Equal-cost multipath allows up to 64 equal-cost next hops for IPv4/IPv6; configured with 'ecmp <n>' under the router context; hashing uses L3/L4 headers per flow.

Blackhole route

A static route with a blackhole or discard next-hop drops matching traffic; commonly used for RTBH DDoS mitigation by advertising a host route to a blackhole.

SAP in SR OS

A service access point maps a port and VLAN (or QinQ encapsulation) to a service such as VPLS or Epipe; it defines how customer traffic enters the service.

VPLS signaling

VPLS on SR OS can use BGP auto-discovery (RFC 4761) or LDP signaling (RFC 4762); both provide multipoint L2 VPN with MAC learning and flooding per VPLS instance.

EVPN route types

EVPN uses BGP route types: Type 2 for MAC/IP, Type 3 for IMET (inclusive multicast), and Type 5 for IP prefix; Type 5 enables L3 symmetric IRB with distributed gateways.

MC-LAG

Multi-chassis LAG uses ICCP over a peer link between two SR OS devices to present a single LAG to an access switch, providing active-active redundancy without spanning tree.

QinQ encapsulation

IEEE 802.1ad QinQ stacks a customer VLAN (C-VLAN) inside a provider VLAN (S-VLAN); SR OS configures it on a SAP with 'qinq' and dot1q encapsulation.

MSTP instances

MSTP (802.1s) maps VLANs to multiple spanning-tree instances, allowing load sharing across links; RSTP (802.1w) is the default on SR OS with edge ports for rapid convergence.

LAG hashing

Link aggregation distributes traffic across member links using a hash of L2/L3/L4 headers; the hash algorithm must match on both ends to avoid out-of-order packets.

SDP in SR OS

A service destination point binds a service to a network transport (LDP or RSVP-TE) across the MPLS core; it carries service traffic between PE routers.

NSP NFM-P

Network Functions Manager - Packet is the NSP component for device management, configuration, and fault management of SR OS devices; it uses NETCONF/YANG and SNMP.

MD-CLI

Model-driven CLI on SR OS 16+ uses a hierarchical, transactional configuration model; changes are staged in a candidate and applied atomically with 'commit'.

gRPC telemetry

SR OS streams counters and state to NSP Analytics via gRPC dial-out; subscriptions are configured under 'system grpc' with a target and sensor paths.

ZTP on SR OS

Zero-touch provisioning boots a device with DHCP option 66/67 or a USB/URL to fetch a boot file, then registers with NSP for full configuration.

NSP intent-based provisioning

An operator defines a service intent (e.g., Epipe, VPLS, VPRN); NSP computes the device configuration and pushes it via NETCONF, ensuring consistency across the network.

NSP RBAC

NSP assigns users scopes (read/write/admin) and roles; it integrates with external AAA (TACACS+/RADIUS) for authentication and authorization of management actions.

NSP REST API

NSP exposes REST/RESTCONF APIs for service creation and inventory; clients authenticate with OAuth2 tokens or basic auth depending on the NSP version.

SR OS IP filter

An ACL applied to a SAP, network port, or router interface; entries match IP fields, ports, DSCP, and TCP flags; default action is configurable (drop or forward).

CPM filter

A control-plane filter (system security cpm-filter) protects the management/control plane from DoS; it is applied to the CPM port and management interfaces.

uRPF modes

Unicast RPF prevents spoofed source addresses: strict mode checks the route to the source via the same interface; loose mode checks only that a route to the source exists.

RPKI origin validation

SR OS supports RPKI ROV via 'origin-validation' to validate BGP origin AS; invalid routes can be marked or dropped, mitigating prefix hijacks.

RTBH mitigation

Remotely triggered blackhole advertises a host route to a blackhole next-hop via BGP, dropping attack traffic at the edge while preserving legitimate traffic.

IPsec on SR OS

IPsec uses IKEv2 with pre-shared keys or certificates; tunnels are configured in an IPsec gateway and applied to a tunnel interface or VPRN for secure transport.

VXLAN overhead

VXLAN adds 50 bytes of overhead (outer IP/UDP/VXLAN); the underlay MTU must be at least 1600 bytes to avoid fragmentation for 1500-byte payloads.

EVPN-VXLAN leaf-spine

SR OS supports EVPN-VXLAN on leaf/spine: VXLAN (UDP 4789) encapsulates L2 frames over an IP underlay; VTEPs are loopback interfaces, and EVPN provides control-plane learning.

Segment routing

SR-MPLS uses MPLS labels (node SID) and SRv6 uses IPv6 segment IDs; SR reduces core state and supports traffic engineering (SR-TE) on SR OS.

SyncE and PTP

SR OS supports SyncE (G.8261/8262) and PTP (IEEE 1588v2) for transport and mobile backhaul; boundary and transparent clock modes distribute frequency and phase.