router alert

This document deprecates the IPv6 Router Alert option. Protocols that use the IPv6 Router Alert option may continue to do so, even in future versions. However, new protocols that are standardized in the future must not use the IPv6 Router Alert option.

This document updates RFC 2711.

The MPLS echo request and MPLS echo response messages, defined in RFC 8029, "Detecting Multiprotocol Label Switched (MPLS) Data-Plane Failures" (usually referred to as LSP ping), are encapsulated in IP packets with headers that include a Router Alert Option (RAO). In actual deployments, the RAO was neither required nor used. Furthermore, RFC 6398 identifies security vulnerabilities associated with the RAO in non-controlled environments, e.g., the case of using the MPLS echo request/reply as inter-area Operations, Administration, and Maintenance (OAM), and recommends against its use outside of controlled environments.

Therefore, this document retires the RAO for MPLS OAM and updates RFC 8029 to remove the RAO from LSP ping message encapsulations. Furthermore, this document explains why RFC 7506 has been reclassified as Historic.

Also, this document recommends the use of an IPv6 loopback address (::1/128) as the IPv6 destination address for an MPLS echo request message.

RFC 4379 defines the MPLS Label Switched Path (LSP) Ping/Traceroute mechanism in which the Router Alert Option (RAO) MUST be set in the IP header of the MPLS Echo Request messages and may conditionally be set in the IP header of the MPLS Echo Reply messages depending on the Reply Mode used. While a generic "Router shall examine packet" Option Value is used for the IPv4 RAO, there is no generic RAO value defined for IPv6 that can be used. This document allocates a new, generic IPv6 RAO value that can be used by MPLS Operations, Administration, and Maintenance (OAM) tools, including the MPLS Echo Request and MPLS Echo Reply messages for MPLS in IPv6 environments. Consequently, it updates RFC 4379.

The initial motivation to request an IPv6 RAO value for MPLS OAM comes from the MPLS LSP Ping/Traceroute. However, this value is applicable to all MPLS OAM and not limited to MPLS LSP Ping/ Traceroute.

The IP Router Alert Option is an IP option that alerts transit routers to more closely examine the contents of an IP packet. The Resource reSerVation Protocol (RSVP), Pragmatic General Multicast (PGM), the Internet Group Management Protocol (IGMP), Multicast Listener Discovery (MLD), Multicast Router Discovery (MRD), and General Internet Signaling Transport (GIST) are some of the protocols that make use of the IP Router Alert Option. This document discusses security aspects and usage guidelines around the use of the current IP Router Alert Option, thereby updating RFC 2113 and RFC 2711. Specifically, it provides recommendations against using the Router Alert in the end-to-end open Internet and identifies controlled environments where protocols depending on Router Alert can be used safely. It also provides recommendations about protection approaches for service providers. Finally, it provides brief guidelines for Router Alert implementation on routers. This memo documents an Internet Best Current Practice.

This document updates the IANA allocation rules and registry of IPv4 and IPv6 Router Alert Option Values. [STANDARDS-TRACK]

This memo describes a new IPv6 Hop-by-Hop Option type that alerts transit routers to more closely examine the contents of an IP datagram. [STANDARDS-TRACK]

This memo describes a new IP Option type that alerts transit routers to more closely examine the contents of an IP packet. [STANDARDS-TRACK]