Re: [Teas] network Slice Endpoint in draft-ietf-teas-ietf-network-slice-definition-00

Adrian Farrel <adrian@olddog.co.uk> Fri, 05 February 2021 22:29 UTC

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Reply-To: adrian@olddog.co.uk
From: Adrian Farrel <adrian@olddog.co.uk>
To: "'Joel M. Halpern'" <jmh@joelhalpern.com>
Cc: teas@ietf.org
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In-Reply-To: <cc3949a4-1e60-7f77-45bd-2470be67d9d5@joelhalpern.com>
Date: Fri, 05 Feb 2021 22:29:04 -0000
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Archived-At: <https://mailarchive.ietf.org/arch/msg/teas/AGImFOZwk4UyY1L7jM47qHSnojQ>
Subject: Re: [Teas] network Slice Endpoint in draft-ietf-teas-ietf-network-slice-definition-00
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Ah, the old "endpoint" discussion.

Yes, Joel is right, we need to disambiguate endpoints from endpoints.
There are traffic endpoints (the sender and receiver of packets), and there
are endpoints of the service (the ingress and egress to the slice).

There is probably a risk that we get sucked in to the wider 5G picture, but
we need to focus (as Joel says) on the IETF network slice.

I suggest "source/destination" and "IETF network slice ingress/egress".

And we can avoid discussion of the wider 5G context, as noted elsewhere in
the draft, by diverting that material into a dedicated document.

Cheers,
Adrian

-----Original Message-----
From: Teas <teas-bounces@ietf.org> On Behalf Of Joel M. Halpern
Sent: 05 February 2021 17:04
To: teas@ietf.org
Subject: [Teas] network Slice Endpoint in
draft-ietf-teas-ietf-network-slice-definition-00

Rereading this draft, I realized that I am either confused by or 
disagree with the description of the "Network Slice Endpoint" contianed 
there.


The endpoint that I think matters is the place where the IETF Network 
Slice Controller starts controlling the QoS and traffic delivery.  The 
Controller doesn't care about the identity of the device outside of that.

Figure 1 in section 4.2 seems to define that endpoint as the network 
slice realiation endpoint, and describes the network slice endpoint as 
the thing outside the IetF network slice.  This seems counter-productive 
to me.  It complicates teh relationship between the endpoitn and the 
service being abstracted.  For example, if the service is beign 
delivered with MPLS, the Network Slice Endpoint likely can not put the 
labels on the packet for the MPLS, as it is outside of the IETF network 
Slice.  So we will need yet another layer of classification, and yet 
more interworking.
Further, someone has to get the queueing right for traffic coming out of 
the Network Slice Endpoint.  But it is not part of the IETF Network 
Slice, so we don't have any way to get it right.

If we define the edge of the space we care about co-incident with the 
edge of the space we influence, things get a lot cleaner.

Yours,
Joel

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