MPLS Network Actions for No Further Fast Reroute

Protection switching for MPLS traffic was first introduced in . Since then, Fast Reroute (FRR) has been successfully used in many MPLS networks to help ensure high availability in the face of failures. If there are multiple failures in a network, there are circumstances where FRR, if applied multiple times, can result in sub-optimal behavior, such as forwarding loops. Thus, it is useful to indicate in the forwarding plane that the attached traffic should not be subjected to further FRR redirection. This document describes a network actions for identifying such traffic to be used in conjunction with “MPLS Network Action (MNA) Header Encodings” as part of the MPLS Network Action architecture.

The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “NOT RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in BCP14 when, and only when, they appear in all capitals, as shown here.

Name: No Further Fast Reroute Action Network Action Indication: The No Further Fast Reroute Action indication is bit postion TBA1. Scope: The No Further Fast Reroute Action is valid in Hop-By-Hop and Select scopes. In-Stack Data: None. Post-Stack Data: None. Packets that indicate the NFFRR action should not be subject to further FRR operations.

The forwarding plane is insecure. If an adversary can affect the forwarding plane, then they can inject data, remove data, corrupt data, or modify data. MNA additionally allows an adversary to make packets perform arbitrary network actions. Link-level security mechanisms can help mitigate some on-link attacks, but does nothing to preclude hostile nodes.

This document requests that IANA allocate a bit position (TBA1) from the MPLS “In-Stack MPLS Network Action Indicator Flags” registry for the No Further Fast Reroute Action. The allocation should reference this document.