[netmod] draft-wilton-netmod-interface-properties-00

[Robert Wilton <[e-mail]>]

Hi,

In the NETMOD session on Wednesday I will spend 5 minutes speaking on 
draft-wilton-netmod-interface-properties-00, that has been created due 
to discussions with various folks to handle interface type specific 
configuration.

The draft isn't particularly long, 21 pages, two thirds of that is just 
examples, and it is presenting a simple idea.

In particular, it is aiming at solving the problem of when statements 
like this:

      augment "/if:interfaces/if:interface" {
        when "derived-from-or-self(if:type, 'ianaift:ethernetCsmacd') or
              derived-from-or-self(if:type, 'ianaift:ieee8023adLag') or
              derived-from-or-self(if:type, 'ianaift:l2vlan') or
              derived-from-or-self(if:type, 'ianaift:ifPwType')" {
          description "Applies to all Ethernet-like interfaces";
        }

and instead proposes this:

     augment "/if:interfaces/if:interface" {
       when "derived-from(if:type, 'ianaifp:ethernet-like')" {
         description
           "Applies to all interfaces that derive from the Ethernet-like
            interface property.";
       }

The core idea being that new identities are defined to represent 
interface properties (like ethernet-like) and the existing interface 
types iana-if-types.yang are updated to also derive from the new 
interface properties.

This simplifies the YANG, should make interface based configuration more 
future proof, since new interface types can also derive from the 
appropriate interface properties.  Of course additional interface 
properties could also be defined.

I'm seeking input from the WG as to whether they like this approach, AND 
also whether the WG drafts: draft-ietf-netmod-intf-ext-yang-05 and 
draft-ietf-netmod-sub-intf-vlan-model-02 should be updated to make use 
of this approach (possibly in a future bis revision to avoid delaying 
publishing the models).

Thanks,
Rob