[j-nsp] BFD Distributed Mode for IPv6

[adamv0025 at netconsultings.com]

> From: James Bensley [mailto:jwbensley at gmail.com]
> Sent: Wednesday, October 03, 2018 10:51 AM
> 
> On Wed, 3 Oct 2018 at 10:13, Mark Tinka <mark.tinka at seacom.mu> wrote:
> > On 3/Oct/18 11:09, adamv0025 at netconsultings.com wrote:
> >
> > If you'd have separate ISIS process for v6 would it be possible to
> > spin up a separate/dedicated BFD process for that ISIS?
> 
> Unless I'm mistaken BFD isn't "multi-tenant", so only one set of BFD packet
> exchanges can exist per-interface, there is no support for multiple BFD
> session on the same interface (by which I mean layer 2 broadcast domain in
> the case of sub-interfaces). This kind of makes sense as BFD is supposed to
> test for unidirectional communication failure of the physical link (the fact that
> it runs in both directions gives bidirectional failure detection). So we can run
> BFDv4 and/or
> BFDv6 on an interface but only one instance per-interface otherwise you'd
> need to negotiate different port numbers for the different instances on the
> same interface?
> 
Yes you're right the main purpose is link failure detection, 

I've been wondering for quite some time why vendors don’t allow us to configure BFD as a standalone protocol very much like any other IGP protocol and instead insist on doing that themselves automatically under the hood.

I imagine the following:
set protocols bfd interface xe-0/0/0 family inet source-address x.x.x.x
set protocols bfd interface xe-0/0/0 family inet mode echo
set protocols bfd interface xe-0/0/0 family inet minimum-interval xx
set protocols bfd interface xe-0/0/0 family inet multiplier x
set protocols bfd interface xe-0/0/1 family inet source-address x.x.x.x
set protocols bfd interface xe-0/0/1 family inet mode echo
set protocols bfd interface xe-0/0/1 family inet minimum-interval xx
set protocols bfd interface xe-0/0/1 family inet multiplier x

set interfaces xe-0/0/0 gigether-options 802.3ad ae0
set interfaces xe-0/0/1 gigether-options 802.3ad ae0
set interfaces ae0 aggregated-ether-options lacp bfd-liveness-detection

set protocols isis interface ae0.0 bfd-liveness-detection
set protocols ospf interface ae0.0 bfd-liveness-detection
set protocols ldp interface ae0.0 bfd-liveness-detection

adam