Re: [mpls] p2mp BFD over MPLS LSP

Greg Mirsky <> Mon, 15 October 2018 14:44 UTC

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From: Greg Mirsky <>
Date: Mon, 15 Oct 2018 07:44:10 -0700
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Subject: Re: [mpls] p2mp BFD over MPLS LSP
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Hi Gyan,
thank you for your very pointed question. The base specification for BFD in
multipoint networks (often referred to as "p2mp BFD") explains that in p2mp
and mp2mp MPLS LSP cases p2mp BFD MAY use IP/UDP encapsulation in Section

   For multipoint LSPs, when IP/UDP encapsulation of BFD control packets
   is used, MultipointTail MUST expect destination UDP port 3784.
   Destination IP address of BFD control packet MUST be in
   range for IPv4 or in 0:0:0:0:0:FFFF:7F00:0/104 range for IPv6.  The
   use of these destination addresses is consistent with the
   explanations and usage in [RFC8029].  Packets identified as BFD
   packets MUST be consumed by MultipointTail and demultiplexed as
   described in Section 5.13.2.  Use of other types of encapsulation of
   the BFD control message over multipoint LSP is outside the scope of
   this document.

In some environments using IP/UDP encapsulation for BFD Control packet is
overburden, and this draft explains how p2mp BFD must be used with G-ACh
encapsulation. Both types, IP/UDP and G-ACh, may be used to monitor MVPN.
Additionally, note that the base p2mp BFD mode does not support tail
notification of the path failure to the head. If the protection action to
be performed not by the tail but the head, you'd need to use BFD for
Multipoint Networks with Active Tail specification. G-ACh encapsulation may
be used in any of these specs.


On Sat, Oct 13, 2018 at 7:14 PM Gyan Mishra <> wrote:

> Hi Greg
> So this Draft would support BFD with IPv6 encap along with the IPV4 encap
> for P2MP MVPN LSP so would this support all MVPN profiles.
> Thank you
> Gyan
> On Sat, Oct 13, 2018, 4:25 PM Greg Mirsky <> wrote:
>> Dear WG Chairs, et al.,
>> as the author of the BFD for Multipoint Networks over
>> Point-to-Multi-Point MPLS LSP (draft-mirsky-mpls-p2mp-bfd) I would like to
>> ask you to consider WG adoption call of the draft. The document addresses
>> non-IP encapsulation of p2mp BFD over MPLS LSP that may be useful if the
>> overhead of IP, particularly IPv6, encapsulation is the concern. The base
>> specification of BFD for Multipoint Networks is at this time in IESG LC.
>> Regards,
>> Greg
>> _______________________________________________
>> mpls mailing list