Hi Greg,
From: Greg Mirsky [mailto:[email protected]]
Sent: Tuesday, June 6, 2017 2:56 PM
To: Xufeng Liu <[email protected]>
Cc: Acee Lindem (acee) <[email protected]>;
[email protected]; [email protected];
[email protected]; [email protected]
Subject: Re: MPLS label and LSE data models
Hi Xufeng,
thank you for helping me with your insight. I have couple follow-up questions:
* yes, grouping mpls-label-stack covers LSE though I cannot see why it
needs id, sequence identifier. I'd expect the label stack already be properly
ordered;
[Xufeng] There are two ways to achieve the ordering: 1) Explicit sequence id,
2) Implicit order of the list items. Personally I feel that the explicit way is
more clear and easier to use, but have no strong objection to the implicit way.
* if we agree that the mpls-label-stack is ordered list, then figuring out
which LSE should have BoS set is indeed benign and may not require to be
explicit;
* as for Static MPLS LSP I propose:
* no need to have outgoing_label and outgoing_labels as the former is
special case of the latter;
* consider whether to use rt-type:mpls-label-stack rather than
rt-type:mpls-label. It gets tricky on transit nodes but we, it seems to me,
need operations on TTL and TC being explicit on ingress.
[Xufeng] Thanks for your suggestion. Will pass to the discussion.
Regards,
Greg
On Tue, Jun 6, 2017 at 8:05 AM, Xufeng Liu
<[email protected]<mailto:[email protected]>> wrote:
Hi Greg,
1. As you mentioned, grouping mpls-label-stack is defined in routing-types,
so MPLS LSE is covered, right?
2. Bottom-of-the-stack flag should not be needed in the model, because the
label stack is a list with sequence ID’s, which tell us the beginning and the
end of the stack.
3. The discussion on static MPLS LSP has started, but not converged yet.
There are still open issues w.r.t. how to model the label stack and stack
operations. Any suggestions would be appreciated. Do you have a proposal?
Thanks,
- Xufeng
From: Greg Mirsky [mailto:[email protected]<mailto:[email protected]>]
Sent: Monday, June 5, 2017 8:44 PM
To: Acee Lindem (acee) <[email protected]<mailto:[email protected]>>
Cc:
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>;
[email protected]<mailto:[email protected]>; [email protected]<mailto:[email protected]>
Subject: Re: MPLS label and LSE data models
Hi Acee,
I think rather of the contrary, Static MPLS LSP must include TC and TTL. And
Bottom-of-the-stack flag as well (I don't see it in grouping mpls-label-stack
of the ietf-routing-types).
Regards,
Greg
On Mon, Jun 5, 2017 at 4:55 PM, Acee Lindem (acee)
<[email protected]<mailto:[email protected]>> wrote:
Greg, et al,
From: Greg Mirsky <[email protected]<mailto:[email protected]>>
Date: Monday, June 5, 2017 at 6:28 PM
To:
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>"
<[email protected]<mailto:[email protected]>>
Cc: Routing WG <[email protected]<mailto:[email protected]>>,
"[email protected]<mailto:[email protected]>" <[email protected]<mailto:[email protected]>>
Subject: MPLS label and LSE data models
Resent-From: <[email protected]<mailto:[email protected]>>
Resent-To: Yingzhen Qu <[email protected]<mailto:[email protected]>>,
<[email protected]<mailto:[email protected]>>, Acee Lindem
<[email protected]<mailto:[email protected]>>, Christian Hopps
<[email protected]<mailto:[email protected]>>,
<[email protected]<mailto:[email protected]>>
Resent-Date: Monday, June 5, 2017 at 6:28 PM
Dear Authors, et.al<http://et.al>,
I've got a question, or several of them, about data models of MPLS label and
MPLS label stack element (LSE). I ahve not followed the discussions and
apologize if these already were considered, discussed.
In the Routing Types document I've found that only MPLS label being modeled but
not the MPLS LSE. As result, models that use rt-types:mpls-label, e.g. YANG
DAta Model for MPLS Static LSPs, defines outgoing labels not as array of LSEs
but as array (leaf-list) of MPLS labels. In the latter document I don't see how
TTL and Traffic Class (TC) are presented for each of labels in the array. Hence
my questions:
* should there be data model of MPLS LSE in rt-types (it does have TTL and
TC but separately);
* should data model of Static MPLS LSP use MPLS LSE model rather than model
of only 20 bit-long label.
Where else so you see a requirement for a label stack with entries that don’t
contain TC and TTL? This seems specific to static provisioning of static LSPs
rather than a general requirement for ietf-routing-types.
Thanks,
Acee
Appreciate you comments.
Regards,
Greg
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