This read-only enumerated value reports the current state of an IS-IS adjacency to a neighboring intermediate system, such as initializing, up, failed, or down. It is the primary at-a-glance health indicator for a specific IS-IS neighbor relationship, letting an administrator immediately see whether routing is actually converged over that link. For example, an operator troubleshooting missing routes to a remote site would poll csIsisISAdjState and find it stuck at failed(3), pointing to an authentication or hello-timing mismatch with that neighbor.