Encapsulating MPLS in UDP

Abstract

This document specifies an IP-based encapsulation for MPLS, called MPLS-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 MPLSin-UDP encapsulation technology must only be deployed within a single network (with a single network operator) or networks of an adjacent set of cooperating network operators where traffic is managed to avoid congestion, rather than over the Internet where congestion control is required. Usage restrictions apply to MPLS-in-UDP usage for traffic that is not congestion controlled and to UDP zero checksum usage with IPv6.

UDP Usage Guidelines

“…By default, UDP requires a checksum for use with IPv6. An option has been specified that permits a zero IPv6 UDP checksum when used in specific environments, specified in [RFC7510], and defines a set of operational constraints for use of this mode. These are summarized below:…”

“…Protocols designed for such networks SHOULD provide mechanisms at the network edge to prevent leakage of traffic into unprovisioned Internet paths (e.g., [RFC7510]). To protect other applications sharing the same path, applications SHOULD also deploy an appropriate circuit breaker, as described in Section 3.1.10.…”

“…Specifications addressing a limited applicability use case or a controlled environment SHOULD identify how, in their restricted deployment, a level of safety is provided that is equivalent to that of a protocol designed for operation over the general Internet (e.g., a design based on extensive experience with deployments of particular methods that provide features that cannot be expected in general Internet equipment and the robustness of the design of MPLS to corruption of headers both helped justify use of an alternate UDP integrity check [RFC7510]). …”

“…An IETF specification targeting a controlled environment is expected to provide an applicability statement that restricts the application traffic to the controlled environment, and it would be expected to describe how methods can be provided to discourage or prevent escape of corrupted packets from the environment (for example, Section 5 of [RFC7510]). …”

“…Designers therefore need to consider other mechanisms to provide equivalent protection (e.g., to restrict use to a controlled environment [RFC7510] Section 3.6).…”