Re: [Detnet-dp-dt] new versions of my slides

[Norman Finn <[e-mail]>]

Sorry!!  Attachment here.

-- Norm
________________________________________
From: Norman Finn
Sent: Sunday, February 26, 2017 2:42 PM
To: Loa Andersson; [e-mail]
Subject: RE: [Detnet-dp-dt] new versions of my slides

Loa,

Slides 2, 4, 7, and 9 (the diagrams) had lots of very minor typos.  I made all fo the labels consistent in the attached version.

Slide 3: "Consider the replicated packet that reaches B  from E and 8,"  I think you meant, "E and 6".

Slide 5: 2nd sub-bullet.  "LB-3 because it is an L-level label taking the packet from F to E".  I think you meant, "A to E"?

One question:

 Who guarantees d-id1 != d-id2?  Maybe I missed it, but I don't see that in the discussions in the slides.

Answering your questions:

Q: Do we agree that this works even if is not optimal.

   Yes, if d-id1 != d-id2.

Q: Do we want to eliminate any of the control plane alternatives.

   I don't.

Q: By using the L-labels as containers for QoS and BW, neither T-Labels or PW-lables can do that, is it clear that we need L-Labels?

As far as the data plane is concerned, I think we need either the L-labels or the d-id labels, but not both.  (Although, without the d-id labels, you have to know that LB-3 + d-pw1 is the same flow as LB-4 + d-pw1, so perhaps it's easier to do without the L-labels.)  Either label could be used for QoS.

But, perhaps we have an issue when creating d-pw labels and/or d-id labels.  The PW creation exchange operates over a tunnel, right?  We have a complex tunnel, not a point-to-point tunnel.  How does the PW creation exchange know what path to follow?  Over what path are the d-id labels created?  In other words, how are the L-labels stitched together?  Equivalently, how are the d-id labels distributed over the paths.

Q: We talk about “detnet pseudo wire”, is that a new type of pseudo wire?

I wouldn't call it anything different.

Q: How do we handle the already existing pseudo wires?

Same as always.  Again, I think the key is defining how you negotiate the path that the branched pseudowire follows.  In my opinion, (subject to finding a counter example that screws everything up), you nail down the paths, either with L-labels or d-id labels, and each d-pw creation (or perhaps first use) creates an instance of the packet discard machine at each combination point.  But, I'm not sufficiently versed in the label protocols to offer an opinion of how that happens.

-- Norm

________________________________________
From: Detnet-dp-dt [[e-mail]] on behalf of Loa Andersson [[e-mail]]
Sent: Sunday, February 26, 2017 2:34 AM
To: [e-mail]
Subject: [Detnet-dp-dt] new versions of my slides

Folks,

I gone over my slides and tighten them up a bit.

I think it is time that we start agree on some of the design decisions
we are making and start taking them as the basis for what we are doing
next.

Slides should be self-explaining, but you can jump slide 3 and get
back to it in the end.

/Loa
--


Loa Andersson                        email: [e-mail]
Senior MPLS Expert                          [e-mail]
Huawei Technologies (consultant)     phone: [phone]