Subject: [Errata Held for Document Update] RFC5884 (5087)

From: RFC Errata System <[email-masked]>
Date: Mon, 6 Nov 2017 15:02:11 -0800 (PST)

The following errata report has been held for document update 
for RFC5884, "Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)". 

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You may review the report below and at:
http://www.rfc-editor.org/errata/eid5087

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Status: Held for Document Update
Type: Editorial

Reported by: Carlos Pignataro <[email-masked]>
Date Reported: 2017-08-16
Held by: Alvaro Retana (IESG)

Section: 7

Original Text
-------------
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.

Corrected Text
--------------
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

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RFC5884 (draft-ietf-bfd-mpls-07)
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Title               : Bidirectional Forwarding Detection (BFD) for MPLS Label Switched Paths (LSPs)
Publication Date    : June 2010
Author(s)           : R. Aggarwal, K. Kompella, T. Nadeau, G. Swallow
Category            : PROPOSED STANDARD
Source              : Bidirectional Forwarding Detection
Area                : Routing
Stream              : IETF
Verifying Party     : IESG