Cathy,
>Thanks for your help!
You're welcome.
>I m still confused that how can we decide the correct SLA, then add the >corresponding policy to the edge router?
The SLA is negotiated between ISP and customers or between ISPs. If such contract is set up it is put into PDB which is used by BB. BB control edge routeror negotiate with other BB by COPS.
>Can you introduce some algorithms for BB and custom to negotiation >SLA, then setup policy Base on SLA and the resources of domain?
It does not need any algo. but a protocol, as COPS.
To the bandwidth allocation between different service classes, RDM or MAR is proposed for DS-TE but it does not limited to that area. MPLS is a transport protocol which enables QoS differentiation and TE in packet networks.
regards