RFC Errata
RFC 5884, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)", June 2010
Note: This RFC has been updated by RFC 7726
Source of RFC: bfd (rtg)
Errata ID: 5087
Status: Held for Document Update
Type: Editorial
Publication Format(s) : TEXT
Reported By: Carlos Pignataro
Date Reported: 2017-08-16
Held for Document Update by: Alvaro Retana
Date Held: 2017-11-06
Section 7 says:
7. Encapsulation [...] The BFD Control packet sent by the ingress LSR MUST be a UDP packet with a well-known destination port 3784 [BFD-IP] and a source port assigned by the sender as per the procedures in [BFD-IP]. The source IP address is a routable address of the sender. The destination IP address MUST be randomly chosen from the 127/8 range for IPv4 and from the 0:0:0:0:0:FFFF:7F00/104 range for IPv6 with the following exception. If the FEC is an LDP IP FEC, the ingress LSR may discover multiple alternate paths to the egress LSR for this FEC using LSP Ping traceroute. In this case, the destination IP address, used in a BFD session established for one such alternate path, is the address in the 127/8 range for IPv4 or 0:0:0:0:0:FFFF:7F00/104 range for IPv6 discovered by LSP Ping traceroute [RFC4379] to exercise that particular alternate path. [...] Or the BFD Control packet sent by the egress LSR to the ingress LSR MAY be encapsulated in an MPLS label stack. In this case, the presence of the fault detection message is indicated as described above. This may be the case if the FEC for which the fault detection is being performed corresponds to a bidirectional LSP or an MPLS PW. This may also be the case when there is a return LSP from the egress LSR to the ingress LSR. In this case, the destination IP address MUST be randomly chosen from the 127/8 range for IPv4 and from the 0:0:0:0:0:FFFF:7F00/104 range for IPv6.
It should say:
7. Encapsulation [...] The BFD Control packet sent by the ingress LSR MUST be a UDP packet with a well-known destination port 3784 [BFD-IP] and a source port assigned by the sender as per the procedures in [BFD-IP]. The source IP address is a routable address of the sender. The destination IP address MUST be randomly chosen from the 127/8 range for IPv4 and from the 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6 with the following exception. If the FEC is an LDP IP FEC, the ingress LSR may discover multiple alternate paths to the egress LSR for this FEC using LSP Ping traceroute. In this case, the destination IP address, used in a BFD session established for one such alternate path, is the address in the 127/8 range for IPv4 or 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6 discovered by LSP Ping traceroute [RFC4379] to exercise that particular alternate path. [...] Or the BFD Control packet sent by the egress LSR to the ingress LSR MAY be encapsulated in an MPLS label stack. In this case, the presence of the fault detection message is indicated as described above. This may be the case if the FEC for which the fault detection is being performed corresponds to a bidirectional LSP or an MPLS PW. This may also be the case when there is a return LSP from the egress LSR to the ingress LSR. In this case, the destination IP address MUST be randomly chosen from the 127/8 range for IPv4 and from the 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6.
Notes:
There are three instances of the IPv4-mapped IPv6 prefix for the IPv4 loopback range 127.0.0.0/8 written as 0:0:0:0:0:FFFF:7F00/104, and it should instead be written as 0:0:0:0:0:FFFF:7F00:0/104.
s/0:0:0:0:0:FFFF:7F00/0:0:0:0:0:FFFF:7F00:0/g (3 replacements)
Same rationale as https://mailarchive.ietf.org/arch/msg/rtg-bfd/DqH_LFCEyUqCLQhffEb7_jU24uQ