rfc2702[Requirements for TE Over MPLS]

key point:
1. The basic idea involves assigning short fixed length label to packets at the ingress to an MPLS cloud.
2. One of the most significant initial applications of MPLS will be in Traffic Engineering.
3. the goal of this document is to highlight the issues and requirements for Traffic Engineering in a large Internet backbone.
4. A description of the basic capabilities and functionality required of an MPLS implementation to accommodate the requirements is also presented.
5. The key performance objectives associated with traffic engineering can be classified as being either: 1. traffic oriented or 2. resource oriented.
6. Traffic oriented performance objectives include the aspects that enhance the QoS of traffic streams. In a single class, best effort Internet service model, the key traffic oriented performance objectives include: minimization of packet loss, minimization of delay, maximization of throughput, end enforcement of service level agreements.Under a single class best effort Internet service model, minimization of packet loss is one of the most important traffic oriented performance objectives.
7. a central function of Traffic Engineering is to efficiently manage bandwidth resources.
8. Minimizing congestion is a primary traffic and resource oriented performance objective.The interest here is on congestion problems that are prolonged rather than on transient congestion resulting from instantaneous bursts. Congestion typically manifests under two scenarios:
     a. When network resources are insufficient or inadequate to accommodate offered load.
     b. When traffic streams are inefficiently mapped onto available resources; causing subsets of network resources to become over-utilized while others remain underutilized.
9. Limitations of Current IGP Control Mechanisms(2.3)
10. MPLS is strategically significant for Traffic Engineering because it can potentially provide most of the functionality available from the overlay model.
11. An induced MPLS graph is analogous to a virtual topology in an overlay model. It is logically mapped onto the physical network through the selection of LSPs for traffic trunks.
12. The Fundamental Problem of Traffic Engineering Over MPLS (3.2)