A cryptographic protocol to protect MPLS labels

We have designed a cryptographic protocol to protect the Multiprotocol Label Switching (MPLS) header used in an Internet service provider (ISP) network. This protocol protects the MPLS header primarily against tampering for purposes of hijacking ISP resources. Secondary goals are protection against replay attack and traffic analysis of ISP traffic. The protocol is fast so as to minimize delay introduced into the high-speed MPLS routers. We use the Blowfish encryption algorithm in our encryption system, and smart cards and the Diffie-Hellman protocol in our key distribution system.