Re: [Lsr] [mpls] Comments on draft-ietf-mpls-spring-entropy-label

2018-07-05 Thread Ketan Talaulikar (ketant) 
Hi Xiaohu,

The IGP drafts define MSD as a framework that enable advertisements for various 
type of SID limits – starting with the Base MSD Type – 1. You are referring to 
this generic construct of MSD in the text you quote below. It is, however, the 
Base MSD (type 1) which is aligned with the definition in PCEP-SR.

IMHO the PCEP-SR draft definition should be updated to refer to this base MSD 
type.

Thanks,
Ketan

From: mpls  On Behalf Of ???(??)
Sent: 06 July 2018 06:55
To: Jeff Tantsura ; stephane.litkowski 
; m...@ietf.org
Cc: lsr@ietf.org; p...@ietf.org
Subject: Re: [mpls] Comments on draft-ietf-mpls-spring-entropy-label

Hi Jeff,

Thanks for your clarification. IMHO, no matter the MSD information is provided 
by whatever protocol, the semantics of the MSD itself should be unified in the 
IETF community. Otherwise, it would introduce unnecessary confusion to 
implementors and operators.

It said in the OSPF-MSD draft：
"

   MSD: Maximum SID Depth - the number of SIDs a node or one of its

   links can support"



What does the "support" exactly mean? It seems at least to me a little bit 
ambiguous compared to the MSD concept as defined in the PCEP-SR draft.



Best regards,

Xiaohu




--
From:Jeff Tantsura mailto:jefftant.i...@gmail.com>>
Send Time:2018年7月6日(星期五) 07:48
To:stephane.litkowski 
mailto:stephane.litkow...@orange.com>>; 徐小虎(义先) 
mailto:xiaohu@alibaba-inc.com>>; 
m...@ietf.org mailto:m...@ietf.org>>
Cc:lsr@ietf.org mailto:lsr@ietf.org>>; 
p...@ietf.org mailto:p...@ietf.org>>
Subject:Re: [mpls] Comments on draft-ietf-mpls-spring-entropy-label

Hi,

Please see inline (MSD section).
Hope this clarifies, thanks!

Cheers,
Jeff



[jeff] both IGP drafts have identical description of the BMI-MSD:
“Base MPLS Imposition MSD (BMI-MSD) signals the total number of MPLS labels a 
node is capable of imposing, including all service/transport/special labels.”
PCEP draft supports only a subset of overall MSD functionality and in general 
it is expected that this info would come from IGPs(BGP-LS).
However the functoriality provided by PCEP is inline with the  BMI-MSD 
definition in the IGP drafts, at the node granularity only though.


3. Section 5 introduces the MSD concept. I wonder whether this concept is 
aligned with the MSD concept as defined in the PCEP-SR draft or the MSD concept 
as defined in the IGP-MSD draft. In PCEP-SR draft, it said "

The "Maximum SID Depth" (1

   octet) field (MSD) specifies the maximum number of SIDs (MPLS label

   stack depth in the context of this document) that a PCC is capable of

   imposing on a packet.



In the IGP-MSD draft, it said "

MSD of type 1 (IANA Registry), called Base MSD is used to signal the

   total number of SIDs a node is capable of imposing, to be used by a

   path computation element/controller.  "



If I understand it correctly, the MSD in this draft==the MSD in PCEP-SR 
draft==the Base MSD (i.e., the MSD of type 1), No?

[SLI] Today, the two IGP drafts does not seem to agree on the definition

ISIS says:” Base MPLS Imposition MSD (BMI-MSD) signals the total number of MPLS
   labels a node is capable of imposing, including all
   service/transport/special labels.”

OSPF says:” MSD of type 1 (IANA Registry) is used to signal the number of SIDs a
   node is capable of imposing, to be used by a path computation
   element/controller and is only relevant to the part of the stack
   created as the result of the computation.”

MSD is just MSD is defines a maximum number of labels to be pushed. This is the 
definition we use and it is compliant with the one used in PCEP-SR:

“The "Maximum SID Depth" (1
   octet) field (MSD) specifies the maximum number of SIDs (MPLS label
   stack depth in context of this document) that a PCC is capable of
   imposing on a packet.”

As we also say: “This includes any kind of labels (service, entropy, 
transport...).”, we are compliant with the BMI-MSD defined in IS-IS.



Best regards,
Xiaohu

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Re: [Lsr] [mpls] Comments on draft-ietf-mpls-spring-entropy-label

2018-07-05 Thread 徐小虎(义先) 
Hi Jeff,

Thanks for your clarification. IMHO, no matter the MSD information is provided 
by whatever protocol, the semantics of the MSD itself should be unified in the 
IETF community. Otherwise, it would introduce unnecessary confusion to 
implementors and operators.

It said in the OSPF-MSD draft：
"
   MSD: Maximum SID Depth - the number of SIDs a node or one of its
   links can support"

What does the "support" exactly mean? It seems at least to me a little bit 
ambiguous compared to the MSD concept as defined in the PCEP-SR draft.

Best regards,
Xiaohu
 



--
From:Jeff Tantsura 
Send Time:2018年7月6日(星期五) 07:48
To:stephane.litkowski ; 徐小虎(义先) 
; m...@ietf.org 
Cc:lsr@ietf.org ; p...@ietf.org 
Subject:Re: [mpls] Comments on draft-ietf-mpls-spring-entropy-label


Hi,

Please see inline (MSD section).
Hope this clarifies, thanks!

Cheers,
Jeff



[jeff] both IGP drafts have identical description of the BMI-MSD:
“Base MPLS Imposition MSD (BMI-MSD) signals the total number of MPLS labels a 
node is capable of imposing, including all service/transport/special labels.”
PCEP draft supports only a subset of overall MSD functionality and in general 
it is expected that this info would come from IGPs(BGP-LS).
However the functoriality provided by PCEP is inline with the  BMI-MSD 
definition in the IGP drafts, at the node granularity only though. 


3. Section 5 introduces the MSD concept. I wonder whether this concept is 
aligned with the MSD concept as defined in the PCEP-SR draft or the MSD concept 
as defined in the IGP-MSD draft. In PCEP-SR draft, it said "
The "Maximum SID Depth" (1
   octet) field (MSD) specifies the maximum number of SIDs (MPLS label
   stack depth in the context of this document) that a PCC is capable of
   imposing on a packet.
 
In the IGP-MSD draft, it said "
MSD of type 1 (IANA Registry), called Base MSD is used to signal the
   total number of SIDs a node is capable of imposing, to be used by a
   path computation element/controller.  "
 
If I understand it correctly, the MSD in this draft==the MSD in PCEP-SR 
draft==the Base MSD (i.e., the MSD of type 1), No?

[SLI] Today, the two IGP drafts does not seem to agree on the definition
ISIS says:” Base MPLS Imposition MSD (BMI-MSD) signals the total number of MPLS
   labels a node is capable of imposing, including all
   service/transport/special labels.”
OSPF says:” MSD of type 1 (IANA Registry) is used to signal the number of SIDs a
   node is capable of imposing, to be used by a path computation
   element/controller and is only relevant to the part of the stack
   created as the result of the computation.”

MSD is just MSD is defines a maximum number of labels to be pushed. This is the 
definition we use and it is compliant with the one used in PCEP-SR:
“The "Maximum SID Depth" (1
   octet) field (MSD) specifies the maximum number of SIDs (MPLS label
   stack depth in context of this document) that a PCC is capable of
   imposing on a packet.”

As we also say: “This includes any kind of labels (service, entropy, 
transport...).”, we are compliant with the BMI-MSD defined in IS-IS.



Best regards,
Xiaohu
_
 
Ce message et ses pieces jointes peuvent contenir des informations 
confidentielles ou privilegiees et ne doivent donc
pas etre diffuses, exploites ou copies sans autorisation. Si vous avez recu ce 
message par erreur, veuillez le signaler
a l'expediteur et le detruire ainsi que les pieces jointes. Les messages 
electroniques etant susceptibles d'alteration,
Orange decline toute responsabilite si ce message a ete altere, deforme ou 
falsifie. Merci.
 
This message and its attachments may contain confidential or privileged 
information that may be protected by law;
they should not be distributed, used or copied without authorisation.
If you have received this email in error, please notify the sender and delete 
this message and its attachments.
As emails may be altered, Orange is not liable for messages that have been 
modified, changed or falsified.
Thank you.
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