Encapsulating MPLS in UDP

This document specifies an IP-based encapsulation for MPLS, calledMPLS-in-UDP for situations where UDP (User Datagram Protocol)encapsulation is preferred to direct use of MPLS, e.g., to enable UDP-based ECMP (Equal-Cost Multipath) or link aggregation. The MPLS- in-UDP encapsulation technology must only be deployed within a singlenetwork (with a single network operator) or networks of an adjacentset of cooperating network operators where traffic is managed to avoidcongestion, rather than over the Internet where congestion control isrequired. Usage restrictions apply to MPLS-in-UDP usage for trafficthat is not congestion controlled and to UDP zero checksum usage withIPv6.