Configuring the Optional Checksum
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.
Context
The optional checksum encapsulates optional checksum TLVs into the Complete Sequence Numbers Protocol Data Units (CSNPs), Partial Sequence Number Protocol Data Units (PSNPs), and Hello packets sent by IS-IS devices. When the peer device receives the encapsulated packets, it checks whether TLVs carried in the packets are correct. If TLVs are not correct, the peer device discards the packets for network security.
Procedure
- Access the system view.
- Access the IS-IS process view.
isis [ process-id ]
- Enable IS-IS optional checksum.
If MD5 authentication or Keychain authentication with valid MD5 authentication is configured on an IS-IS interface or area, IS-IS devices send Hello packets and SNP packets carrying no checksum TLVs and verify the checksum of the received packets.