- Written by Subham Burnwal
- Posted on January 5, 2026
- Updated on January 5, 2026
- 908 Views
IS-IS LSP out-delay is a feature implemented to mitigate transient micro-loops that can occur during topology changes in an IS-IS network.When a topology change occurs (e.g., a link state or metric change), different routers in the network receive and process the updated Link State PDUs (LSPs) at slightly different times. This can lead to a transient state where some routers have updated their Forwarding Information Base (FIB) based on new LSPs, while others have not, causing traffic to be incorrectly forwarded and forming micro-loops.