This is the network model and where our COPS extension fits.
To support traffic engineering, PDP's and PEP's exchange tunnel and filter information via COPS. Two key parameters are
For example, when a PEP (that is, a router) receives tunnel Requests, it needs to interface with MPLS to setup or tear-down LSP's. Whenever something goes wrong with the LSP's, the router needs to notify the problem to the PDP immediately. When a PEP receives filter Requests, it setup packet filters to "pipe" user data into the tunnel(s).
The COPS (client and server) extension (with MPLS LSP interface, supporting 5-tuple and BGP filters) had been developed for the cancelled Lucent PacketStar Router project. Nothing is coming out of 10K+ lines of code! Sigh!!
P. Pan, H. Schulzrinne, P. Calhoun, DIAMETER: Policy and Accounting Extension for SIP, August, 1998.
G. Zorn, P. Pan, P. Calhoun, DIAMETER Framework, August, 1998.