Multi-purpose Special Purpose Label for Forwarding Actions
draft-kompella-mpls-mspl4fa-03

Abstract

The MPLS architecture introduced Special Purpose Labels (SPLs) to indicate special forwarding actions and offered a few simple examples, such as Router Alert. In the two decades since the original architecture was crafted, the range, complexity and sheer number of such actions has grown; in addition, there now is need for "associated data" for some of the forwarding actions. Likewise, the capabilities and scale of forwarding engines has also improved vastly over the same time period. There is a pressing need to match the needs with the capabilities to deliver the next generation of MPLS architecture. In this memo, we propose an alternate mechanism whereby a single SPL can encode multiple forwarding actions and carry data (if any) associated with the actions, some in the label stack and some after the label stack. This proposal also solves the problem of scarcity of base SPLs. As proof of its utility and flexibility, this approach can immediately address several use cases: * to carry an Entropy Label for better load balancing; * to carry a Flow-Aggregate Selector for IETF network slicing; * to signal that further fast reroute may have harmful consequences; * to indicate that there is relevant data after the label stack; * among others.

Authors

Kireeti Kompella
Vishnu Pavan Beeram
Tarek Saad
Israel Meilik

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