Hi, 发件人: netmod [mailto:[email protected]] 代表 Andy Bierman 发送时间: 2015年8月28日 0:25 收件人: Rob Shakir 抄送: [email protected] 主题: Re: [netmod] Motivations for Structuring Models
On Thu, Aug 27, 2015 at 6:56 AM, Rob Shakir <[email protected]<mailto:[email protected]>> wrote: NETMOD, One of the chairs encouraged me to post this to the list. I didn’t really find how it fits in to the existing threads, but I wanted to make an observation. It strikes me that there is a need to take a step back from the debate of whether /device is a good idea or not. As a user of something that results from compiling/generating bindings from a YANG model, I have two requirements: * I need to be able to compose the right modules to be able to get the functionality that that the thing I’m trying to configure uses. * Let’s say I want to configure some OAM continuity checking functions - for both MPLS and IP. * Right now, I have the choice of ‘ietf-lspping’ which defines /lsp-pings, then ‘mplstp-oam’ which defines /mplstp-oam. Presumably then we’ll have ‘ietf-ip-oam’ and then ‘ietf-ipv6-oam’. * As a developer - how do I figure out which models I need to build my OAM function. Do I have to trawl some directory to find all of the different fragments of OAM [Qin]: I think this is also what LIME WG is trying to solve by defining generic YANG model for OAM to provide technology independent framework. Please take a look at LIME WG charter: http://datatracker.ietf.org/wg/lime/charter/ * Do I then need to accept the complexity of dealing with the fact that the structures of LSP pings is completely different to the IP OAM structures? [Given that there is no co-ordination of models, then this will happen.] I think this is something we need to try to avoid. I believe coordination of these models are really needed. * As someone that is building YANG models, how do I know where I should leaf-ref too. * Let’s say I want to tie an OAM probe to some protocol liveliness - where do I point my leafref to? At the moment, without some structure, than any path that is specified is pointing to some placeholder location, until we agree where the structure might sit. [Qin]: Two comments: 1. I think draft-rtgyangdt-rtgwg-device-model-00 provide a good structure for these OAM models organization but not limited to provide structure for OAM model organization. +--rw logical-network-elements +--rw networking-instances +--rw networking-instance* [networking-instance-name] +--rw oam-protocols | +--rw bfd | +--rw cfm | +--rw twamp 2. draft-tissa-lime-yang-oam-model also provide a good common structure for OAM models organization. LIME WG is chartered to work on generic YANG model for OAM (the relevant draft is draft-tissa-lime-yang-oam-model)and provides a common structure for various OAM technologies, technology specific OAM data models will be worked on respective protocol WGs(e.g., BFD, MPLS). Therefore based on LIME charter (http://datatracker.ietf.org/wg/lime/charter/), the relation with protocol based OAM models can be depicted, for example, as follows: +-+-+-+-+-+ | LIME gen| |OAM YANG | +-+-+-+-+-+ | | +---------------------------------------------------------+ | | | | | +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ | CFM | | MPLS-TP | | MPLS | | IP | . . .| foo | |OAM YANG | |OAM YANG | |OAM YANG | |OAM YANG | |OAM YANG | +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ +-+-+-+-+-+ | | | | | | +-+-+-+-+-+ +-+-+-+-+-+ | +-+-+-+-+-+ | | MPLS-TP | | MPLS | | . . .| foo | | |sub tech | |sub tech | | |sub tech |
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