Hi Linda, thank you for your comments.
Yes, the model concerns interactions between agents and clients. The nodes in the model refer to the entities that are referred to in the topology - typically the hosting device as a whole, not just the forwarding engine within the device. The architecture document you mention includes a description of a topology manager in section 5.1; this model will address the need of such application. The service overlay indicates one way in which the model can be used. It is intended as an example that illustrates the flexibility of the model. One key aspect concerns the ability to represent vertical layering relationships; the example shows that the same overlay could map onto several underlays, which is a requirement e.g. when you want to represent a "physical" layering along with logical layering, to know e.g. which physical node/device is supporting a gibven overlay node, without the need to iteratively traverse through multiple layers. I am not sure I understand your comment that it "is definitely meant for clients not towards individual nodes". It is intended to represent relationships between nodes in layered topologies; it would be exposed by an agent to a client. --- Alex From: Linda Dunbar [mailto:[email protected]] Sent: Friday, June 26, 2015 10:03 AM To: '[email protected]'; Alexander Clemm (alex); Jan Medved (jmedved); Robert Varga -X (rovarga - PANTHEON TECHNOLOGIES at Cisco); [email protected]; Hariharan Ananthakrishnan; Tony Tkacik -X (ttkacik - PANTHEON TECHNOLOGIES at Cisco) Subject: comments to draft-ietf-i2rs-yang-network-topo-01 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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