Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01

["Joel M. Halpern" <[e-mail]>]

Let me be real clear.  I know that the topology draft is an adopted I2RS 
working item, and I do not expect that to change.  I am not asking that 
it change.  I think it was a bad fit for our scope, but so be it.

I felt I had to say something when someone said "but I2RS architecture 
looks like X because we have the topology draft."

Having the draft does not change the WG agreed architecture.  Which you 
have confirmed in separate email.

Yours,
Joel

On 6/30/15 3:41 PM, Susan Hares wrote:
> Joel:
> <wg draft author hat on>
> The use cases have lots of virtual topologies, and I not received any
> feedback on these use cases. It would useful for you to comment on which of
> these use cases you do not feel is useful.
> <wg draft author hat off>
>
> <wg chair hat on>
> Joel - it sounds like you are questioning the protocol independent topology
> is appropriate for the charter of I2RS.  Charter questions are appropriate
> only during charter adoption. The charter has been adopted in March 2015.
> If you felt you were not heard during this discussion, please send a note to
> the chairs and copy the AD.   The I2RS chairs need to discuss re-opening
> charter issues with the I2RS AD (Alia Atlas).
>
> The time to discuss the scope of the draft-ietf-i2rs-yang-network-top-01
> draft aligning with the charter was during adoption. I do not perceive that
> you are questioning whether this draft aligns with the charter.
> <wg chair hat off>
>
> Sue
>
> -----Original Message-----
> From: i2rs [mailto:[e-mail]] On Behalf Of Joel M. Halpern
> Sent: Monday, June 29, 2015 5:06 PM
> To: Linda Dunbar; Igor Bryskin; Juergen Schoenwaelder
> Cc: [e-mail]; '[e-mail]'; [e-mail]; Hariharan
> Ananthakrishnan; [e-mail]; [e-mail]; Jan Medved (jmedved)
> Subject: Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01
>
> You may recall that I have expressed concern about many times about how the
> network topology draft fits the I2RS scope.  It is still not clear to me
> that it is an I2RS item, although it is clearly useful for things talking to
> the I2RS Agent.
>
> Yours,
> Joel
>
> On 6/29/15 5:01 PM, Linda Dunbar wrote:
>> Joel, Igor, Juergen,
>>
>> Thanks for the feedback. Actually I always thought I2RS Agent is within a
> single routing engine until reading the "I2RS Topology" draft.
>>
>> I see draft-ietf-i2rs-rib-info-model-06 as a very clear and good
> specification for information exchange between a routing engine and its
> client. It reflects one single node's RIBs associated with multiple Routing
> Instances supported by the routing engine.
>>
>> But the "I2RS Topology", which is also a very good specification
> describing the network view of topologies (which consists of multiple nodes
> and links among them), is more suited for the entity that manages multiple
> routing nodes.
>>
>> RIBs of one routing engine and "topology of multiple routing engines"
> definitely represent different perspectives: one is node view, another one
> is the network view.
>>
>>
>> In order to make I2RS widely adopted by the industry, it is very important
> not to make it too complicated. Routing is not simple to start with,
> therefore, it becomes especially more important to keep I2RS specification
> simple and to the point.
>>
>> Therefore, I suggest to have a paragraph in the "network-topo" draft to
> describe that this is for the network view, it is for clients who
> manage/monitor multiple routing engines.
>>
>> My two cents.
>>
>> Linda
>>
>> -----Original Message-----
>> From: Igor Bryskin [mailto:[e-mail]]
>> Sent: Monday, June 29, 2015 1:33 PM
>> To: Joel M. Halpern; Linda Dunbar; Juergen Schoenwaelder
>> Cc: [e-mail]; '[e-mail]'; [e-mail];
>> Hariharan Ananthakrishnan; [e-mail]; [e-mail]; Jan
>> Medved (jmedved)
>> Subject: RE: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01
>>
>> I agree with Joel,
>>
>> To answer Linda's question: if I2RS agent manages/represnts multiple
> physical devices, the interface between the agent and the devices is out of
> scope of I2RS. Note that such interface needs to be standardized only if one
> considers a scenario where an I2RS agent controls devices from different
> vendors. IMHO this scenario is unlikely, and at least for now it is safe to
> assume that said interface is private.
>>
>> Cheers,
>> Igor
>>
>> -----Original Message-----
>> From: i2rs [mailto:[e-mail]] On Behalf Of Joel M. Halpern
>> Sent: Monday, June 29, 2015 2:01 PM
>> To: Linda Dunbar; Juergen Schoenwaelder
>> Cc: [e-mail]; '[e-mail]'; [e-mail];
>> Hariharan Ananthakrishnan; [e-mail]; [e-mail]; Jan
>> Medved (jmedved)
>> Subject: Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01
>>
>> Juergen is correct that by the I2RS definition an I2RS Agent is part of,
> and associated with, a single routing element.
>>
>> It is true that the routing element may itself be a controller supporting
> and interacting with multiple forwarding elements.  That is not required,
> and not discussed, by I2RS.  As far as I2RS is concerned, the multiplicity
> is that the relationship between I2RS Clittns and I2rS agents is N:M.  That
> is, a client may be working with multiple agents,
>> and an agent may be communicating with multiple clients.   But it is
>> still the case that the agent is collocated with the routing system, and
> is not in a separate controller from the routing system.
>>
>> Yours,
>> Joel
>>
>> On 6/29/15 10:46 AM, Linda Dunbar wrote:
>>> Juergen,
>>>
>>> One I2RS agent can interface with multiple routing elements.
>>>
>>> The network view (which consists of multiple nodes, i.e. topology) has to
> be over multiple nodes. Therefore, it is the interface between client and
> Agent. Whereas, there are commands to individual routing element.
>>>
>>> Linda
>>> -----Original Message-----
>>> From: Juergen Schoenwaelder
>>> [mailto:[e-mail]]
>>> Sent: Monday, June 29, 2015 3:28 AM
>>> To: Linda Dunbar
>>> Cc: '[e-mail]'; [e-mail]; Jan Medved (jmedved);
>>> [e-mail]; [e-mail]; Hariharan
>>> Ananthakrishnan; [e-mail]
>>> Subject: Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01
>>>
>>> Linda,
>>>
>>> according to draft-ietf-i2rs-architecture-09, an I2RS agent is part of a
> routing element. I am not sure your understanding "I2RS Agent is like the
> SDN controller" is consistent with the architecture document.
>>>
>>> /js
>>>
>>> On Fri, Jun 26, 2015 at 05:03:25PM +0000, Linda Dunbar wrote:
>>>> Alex, et al,
>>>>
>>>> The I2RS architecture depicts two types of interfaces:
>>>>
>>>> -          One is the interface between Agent and Client, and
>>>>
>>>> -          another is the interface between Agent and Routing entities.
>>>>
>>>>
>>>> The network model and inventory are more for the interface between Agent
> and the Clients,  isn't it? One single routing engine doesn't need to know
> the overall topology and inventory information of other nodes, even though
> some may do.
>>>>
>>>>
>>>> And the /nd:network/nd:node and Termination points are more for the
> interface between the Agent and the Forwarding Engine, isn't it?
>>>>
>>>> IMHO, the information models should be oriented around the I2RS
> architecture. I.e. with description on where those information models are
> applicable, making it easier to differentiate from other IETF WGs work (such
> as L2VPN, L3VPN, or SFC). I recall there were some debates at the Dallas
> I2RS session.
>>>>
>>>> I2RS Agent is like the SDN controller, which can inform clients about
> the topology information, instruct routes to routing engine of multiple
> nodes, and retrieve link & termination points status from each of those
> nodes.
>>>>
>>>> The "Service Overlay" in Section 3.4.8 is definitely meant for clients
> not towards individual nodes. Mixing them all together make it confusing.
>>>>
>>>> Cheers,
>>>>
>>>> Linda Dunbar
>>>>
>>>>
>>>
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>>>> https://www.ietf.org/mailman/listinfo/i2rs
>>>
>>>
>>
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