After Intermediate System to Intermediate System (IS-IS) authentication is configured, authentication information can be encapsulated into Link State Protocol Data Units (LSPs) and Sequence Number Protocol Data Units (SNPs) to ensure the packet transmission security. By default, authentication is not configured for IS-IS. Configuring authentication is recommended to ensure system security.
The optional checksum encapsulates optional checksum Type-Length-Values (TLVs) into Sequence Number Protocol Data Units (SNPs) and Hello packets to ensure packet correctness, improving network security.