Re: [Detnet-dp-dt] high level questions on detnet dataplane

[Carlos Jesús Bernardos Cano <[e-mail]>]

Hi Loa,

On Wed, 2017-02-22 at 18:32 +0800, Loa Andersson wrote:
> Folks,
> 
> two questions, the first because I've be taling it for granted, the 
> second brought up bu two indenpendent people I talked about DetNet
> with.
> 
> - is a design criteria that the existing MPLS control plane protocols
>    shall be able to use with the DetNet dataplane?
> 
> - I've heard the opinion (from two different directions) that doing
>    replication/elimination other than at the egress/ingress will make
> the
>    solution to complicated. Do we have a good motiation why we need
> it?

I also have this question in mind. I've checked draft-ietf-detnet-dp-
alt-00 and found this:

"
4.5.  #5 Flow duplication and merging

[...]

   The solution alternative has to provide means for end systems, relay
   and edge nodes to be able to duplicate packets into duplicate flows,
   and later merge the flows into one for duplicate elimination.  The
   duplication and merging may take place at multiple points in the
   network in order to ensure that one (or more) equipment failure
   event(s) still leave at least one path intact for a deterministic
   networking flow.  The goal is again to enable hitless 1+1 protection
   in a way that no packet gets lost or there is no ramp up time when
   either one of the paths fails for one reason or another.
"

Not completely clear to me why we need to allow duplication and merging
at multiple points. 

I have also another question: are we considering somehow the
requirements that some detnet applications (e.g., crosshauling) might
require bidirectional flows to be symmetric?

Thanks,

Carlos

> 
> /Loa