IS-IS Part 1: Single-Area Fundamentals, Adjacencies, and LSDB Synchronization

Fri, 30 Oct 2026 00:00:00 +0000

This guide covers Single-Area IS-IS (Area 49.0001) configuration across a 6-node Nokia SR OS topology in Containerlab, ISO Network Entity Title (NET) addressing, point-to-point adjacency formation, and Link-State Database (LSDB) synchronization.

SR OS Version: 25.7.R1

CLI Mode: MD-CLI (Model-Driven CLI)

[!NOTE] Base Interface Prerequisites: This lab builds upon the physical foundation established in OSPF Part 1: Topology Setup and Interface Addressing. Ensure that cards (iom-1), MDAs (me6-100gb-qsfp28), port breakouts (port 1/1/c1 connector breakout c1-100g), system loopbacks, and /30 point-to-point IP interfaces are operational prior to activating IS-IS.

IS-IS Part 2: Multi-Area Hierarchy, ATT Bit, and Route Leaking

Tue, 03 Nov 2026 00:00:00 +0000

This guide covers the design, provisioning, and verification of Multi-Area IS-IS across the Nokia SR OS topology. We examine Level 1 and Level 2 database partitioning, the Attached (ATT) bit default routing mechanism, route summarization with black-hole loop prevention, and policy-based Level 2 to Level 1 route leaking using the Up/Down bit.

SR OS Version: 25.7.R1

CLI Mode: MD-CLI (Model-Driven CLI)

[!NOTE] Prerequisites and Physical Foundation: This lab builds directly upon the operational single-area fabric established in IS-IS Part 1: Single-Area Fundamentals, Adjacencies, and LSDB Synchronization. Base interface configuration, card provisioning, port breakouts, and /30 transit links remain in service.

IS-IS on Dennis Mwangi

IS-IS Part 1: Single-Area Fundamentals, Adjacencies, and LSDB Synchronization

IS-IS Part 2: Multi-Area Hierarchy, ATT Bit, and Route Leaking