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

[Juergen Schoenwaelder <[e-mail]>]

Sue,

I agree with Joel.

/js

On Tue, Jun 30, 2015 at 03:43:30PM -0400, Susan Hares wrote:
> Juergen:
> 
> Please comment on which of the virtual topology use cases in the I2rs use
> case requirements document are not appropriate.  As the editor, I'd love
> comments on the draft.   As WG input, this guides the chair's acceptance of
> work. 
> 
> Sue 
> 
> -----Original Message-----
> From: i2rs [mailto:[e-mail]] On Behalf Of Juergen Schoenwaelder
> Sent: Tuesday, June 30, 2015 1:41 AM
> To: Joel M. Halpern
> Cc: [e-mail]; '[e-mail]'; [e-mail]; Hariharan
> Ananthakrishnan; [e-mail]; [e-mail]; Igor Bryskin; Linda
> Dunbar; Jan Medved (jmedved)
> Subject: Re: [i2rs] comments to draft-ietf-i2rs-yang-network-topo-01
> 
> I have been in the same boat but some people thought it is really important
> to do a generic topology model in I2RS so here we go.
> 
> /js
> 
> On Mon, Jun 29, 2015 at 05:06:17PM -0400, Joel M. Halpern wrote:
> > 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
> > >>>
> > >>>
> > >>
> > >>>_______________________________________________
> > >>>i2rs mailing list
> > >>>[e-mail]
> > >>>https://www.ietf.org/mailman/listinfo/i2rs
> > >>
> > >>
> > >
> > >_______________________________________________
> > >i2rs mailing list
> > >[e-mail]
> > >https://www.ietf.org/mailman/listinfo/i2rs
> > >
> 
> -- 
> Juergen Schoenwaelder           Jacobs University Bremen gGmbH
> Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
> Fax:   [phone]         <http://www.jacobs-university.de/>
> 
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-- 
Juergen Schoenwaelder           Jacobs University Bremen gGmbH
Phone: [phone]         Campus Ring 1 | 28759 Bremen | Germany
Fax:   [phone]         <http://www.jacobs-university.de/>