Conditions to form IS-IS adjacency 1. MTU must match. 2. IS level must match. Level 1 and level 1 router can form adjacency, level 1 router can form adjacency with level1/2 router this is because this router has two IS databases and one is level 1 database. Level 2 and level 2 router can form … Continue reading Intermediate System-Intermediate System Basics →