Re: [Idr] [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10

"Susan Hares" <> Wed, 08 March 2017 15:27 UTC

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From: Susan Hares <>
To: "'Tomotaki, Luis M'" <>, 'Shitanshu Shah' <>, 'Ron Bonica' <>,,,
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Date: Wed, 08 Mar 2017 10:22:33 -0500
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Subject: Re: [Idr] [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10
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Thank you for letting me know you desire for this feature.   Since Ron had
additional questions, I'll let him start off this discussion. 




From: Idr [] On Behalf Of Tomotaki, Luis M
Sent: Tuesday, March 7, 2017 11:11 PM
To: Shitanshu Shah; Susan Hares; 'Ron Bonica';;;
Subject: Re: [Idr] [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10


Ron and Sue,

>From a service provider perspective, exchanging the SLA information between
the PE and CE would be very beneficial and could be widely used.  I think
this is particular important in service provider's L3VPN networks where the
customers or service providers currently do not have full visibility to the
QoS policy in the other end of the connection but still needs matching CE-PE
SLA/QoS policies to achieve the correct two-way traffic prioritization
behavior during congestion.  In this example, once the SLA information
exchange is standardized, my expectation is that the different CE/PE vendors
would be able to automatically update in a vendor specific way, the SLA/QoS
policies based on the SLA information provided via BGP.  




From: Shitanshu Shah [] 
Sent: Monday, March 6, 2017 9:31 AM
To: Susan Hares <>; 'Ron Bonica' <>;;;
Subject: [E] Re: [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10


Hi Sue,


Following is what I had responded to Ron. Hopefully that


To break it down in two point response,


1) This draft is not changing how SLA is established at first place. The
draft is providing a method to convey this a priori established SLA to help
reduce lot of manual complexities and errors to admin. Thus given a
knowledge of what SLA is established, in general devices should be capable
to support that established SLA.



2) If there still are any issues in implementing exchanged SLA in
forwarding, we think they either are implementation specific or of temporary
nature where for example enough resources not available at any specific
point of a time.


We feel that in current state of the draft, it can be largely useful in




One can imagine though even establishment of SLA also can be done via
exchanging it over bgp. However, negotiation of SLA does not have to be
clubbed with exchange of SLA. Negotiation of SLA is not in this scope.






From: Susan Hares <>
Sent: Saturday, March 4, 2017 8:31 AM
To: 'Ron Bonica'; 'Shitanshu Shah';;;
Subject: RE: [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10 




Please address Ron's comment about widely deployed.  I believe this was part
of Alvaro's comments. 




From: rtg-dir [] On Behalf Of Ron Bonica
Sent: Thursday, February 23, 2017 12:07 PM
To: Shitanshu Shah;;;
Subject: Re: [RTG-DIR] RtgDir review: draft-ietf-idr-sla-exchange-10




The draft is internally consistent. But given what is left out of scope, I
wonder if the new attributes will ever be widely deployed.





This document might benefit from discussion of operational issues. I assume
that when a BGP listener learns a route with the SLA Exchange Attribute, it
provisions class of service forwarding classes on interfaces.


##svshah, though this is one desired use of exchanging SLA content, the
draft focuses on transporting SLA content from the SLA Producer to the SLA
Consumer. Processing of the QoS attribute content, at the SLA Consumer, is
outside the scope of this document.


##svshah, Let me know if you have a suggestion to make description clearer
in Section 1 and 2 to highlight this.



I also assume that a) it takes time to provision class of service forwarding
classes and b) the number of forwarding classes that can be provisioned are
finite. What does the BGP listener do when the number of forwarding classes
requested exceeds its capacity to deliver? 


##svshah, Since scope of the document is to transport SLA content from the
SLA Producer to the SLA Consumer, the document considers error handling in
the context of transporting data and thus any formating errors and semantics
errors within that context. Any errors in the context of processing QoS
attribute content at the SLA Consumer is outside the scope of the document.