Nokia NRS II Composite (IS-IS) study guide
Nokia NRS II Composite (IS-IS) · Work through your exam, one topic at a time.
The Nokia NRS II Composite (IS-IS) is an independent-study target for network engineers who already work with IP/MPLS routing and want to demonstrate depth in Intermediate System to Intermediate System as implemented on Nokia SR OS. Candidates typically hold the Nokia NRS I level or equivalent hands-on experience, and use this exam to validate that they can design, configure and troubleshoot IS-IS in service-provider and large enterprise networks. The Nokia NRS II Composite (IS-IS) study guide has 12 sections and about 3,174 words.
01IS-IS Fundamentals and Protocol Operation
IS-IS is a link-state interior gateway protocol standardised in ISO 10589 for CLNP and extended by RFC 1195 to carry IP. The NRS II composite expects you to know its PDU families, its two-level hierarchy, and the operational differences from OSPF that appear in Nokia SR OS outputs.
300 words, about 2 min02IS-IS Addressing
Addressing is where many candidates lose easy marks: NSAP format, NET, system ID length, area address rules, and how Nokia SR OS derives or accepts these values. An NSAP is the ISO address; a NET is an NSAP whose NSEL byte is 00.
280 words, about 1 min03NSAP/NET Structure and Area Design
Area design questions test whether you can plan contiguous L1 areas, a contiguous L2 backbone, summarization points, and stable NETs without creating black holes. L1 areas should be contiguous; the L2 backbone must be contiguous across all L1/L2 routers.
262 words, about 1 min04IS-IS Adjacency Formation and Neighbor State Machine
The exam checks the IIH fields that must match, the three adjacency states, and the common reasons an adjacency stays in Initializing. IIH carries circuit type, system ID, holding time, area addresses, protocols supported, interface addresses and authentication.
251 words, about 1 min05Link-State Database
You must read LSP IDs, sequence numbers, checksums, lifetimes and flags, and explain how the LSDB differs per level. Each router originates its own LSPs; the LSDB is built from all routers' LSPs for a given level.
265 words, about 1 min06LSP Flooding and Synchronization
Flooding questions ask how LSPs reach every router reliably, what CSNP and PSNP do, and why mesh groups exist. Flooding is reliable: an LSP is sent to all adjacencies except the one it arrived on, and it is acknowledged.
249 words, about 1 min07SPF Computation and Route Selection
The exam tests Dijkstra operation per level, how L1 and L2 routes differ, and how Nokia SR OS chooses among competing routes. IS-IS runs a separate SPF for Level 1 and Level 2.
266 words, about 1 min08IS-IS Levels, Area Boundaries and Inter-Area Routing
This domain tests the roles of L1, L2 and L1/L2 routers, the ATT bit, route leaking and the requirement for a contiguous L2 backbone. L1 routers stay inside one area and hold only L1 LSPs.
254 words, about 1 min09IS-IS Metrics
Metric questions cover narrow versus wide metrics, default values, per-level metric configuration and the effect of metric style on path selection. The narrow metric is 6 bits, range 0-63, with a default of 10 per interface.
243 words, about 1 min10Wide Metrics and Traffic Engineering Extensions
This domain tests the TE TLVs and sub-TLVs, the difference between IGP metric and TE metric, and the prerequisites for MPLS TE CSPF. TLV 22 advertises extended IS reachability; TLV 135 advertises extended IP reachability.
274 words, about 1 min11IPv6 and Multi-Topology IS-IS
The exam tests single-topology versus multi-topology operation, the IPv6 TLVs, and when multi-topology is required. Single-topology IS-IS runs one SPF for both IPv4 and IPv6, so the IPv4 and IPv6 topologies must be congruent.
257 words, about 1 min12IS-IS on Nokia SR OS: Configuration, Verification and Troubleshooting
This domain tests practical SR OS configuration, show commands, and a structured approach to adjacency and route problems. Base configuration is under configure router isis <instance : area-id, level-capability, interfaces, metrics and authentication.
273 words, about 1 min