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

Forwarding to list. 

Sue 

-----Original Message-----
From: Susan Hares [mailto:shares@ndzh.com] 
Sent: Tuesday, June 30, 2015 3:31 PM
To: 'Linda Dunbar'; 'Igor Bryskin'; 'Joel M. Halpern'; 'Juergen
Schoenwaelder'
Cc: 'nitin_bahadur@yahoo.com'; 'i2rs@ietf.org'; 'ttkacik@cisco.com';
'Hariharan Ananthakrishnan'; 'rovarga@cisco.com'; 'alex@cisco.com'; 'Jan
Medved (jmedved)'
Subject: RE: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01

Linda:

Thank you for the feedback on the draft-ietf-i2rs-yang-network-topo-01
draft.  This is useful feedback to the authors as we try to explain the I2RS
work to customers. 

Sue 

-----Original Message-----
From: i2rs [mailto:i2rs-bounces@ietf.org] On Behalf Of Linda Dunbar
Sent: Monday, June 29, 2015 5:02 PM
To: Igor Bryskin; Joel M. Halpern; Juergen Schoenwaelder
Cc: nitin_bahadur@yahoo.com; 'i2rs@ietf.org'; ttkacik@cisco.com; Hariharan
Ananthakrishnan; rovarga@cisco.com; alex@cisco.com; Jan Medved (jmedved)
Subject: Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01

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:IBryskin@advaoptical.com]
Sent: Monday, June 29, 2015 1:33 PM
To: Joel M. Halpern; Linda Dunbar; Juergen Schoenwaelder
Cc: nitin_bahadur@yahoo.com; 'i2rs@ietf.org'; ttkacik@cisco.com; Hariharan
Ananthakrishnan; rovarga@cisco.com; alex@cisco.com; 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:i2rs-bounces@ietf.org] On Behalf Of Joel M. Halpern
Sent: Monday, June 29, 2015 2:01 PM
To: Linda Dunbar; Juergen Schoenwaelder
Cc: nitin_bahadur@yahoo.com; 'i2rs@ietf.org'; ttkacik@cisco.com; Hariharan
Ananthakrishnan; rovarga@cisco.com; alex@cisco.com; 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:j.schoenwaelder@jacobs-university.de]
> Sent: Monday, June 29, 2015 3:28 AM
> To: Linda Dunbar
> Cc: 'i2rs@ietf.org'; alex@cisco.com; Jan Medved (jmedved); 
> rovarga@cisco.com; nitin_bahadur@yahoo.com; Hariharan Ananthakrishnan; 
> ttkacik@cisco.com
> 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
>>
>>
>
>> _______________________________________________
>> i2rs mailing list
>> i2rs@ietf.org
>> https://www.ietf.org/mailman/listinfo/i2rs
>
>

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