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Requested revision
Standard:802.1Qcp-2018Clause:48.6.3.3
Clause title:Definition for the ieee802-dot1q-bridge YANG module
Rationale for revision
The IEEE 802.3 YANG module (ieee802-ethernet-interface.yang) allows the
end-user to use the ethernet YANG nodes with other interfaces derived from
ethernetCsmacd (this could be proprietary, state-of-the-art, or from other
standards); however the IEEE 802.1Q bridge YANG model does not allow this for
the bridge-port YANG nodes. Therefore there is an incompatibility issue when
using both these YANG models together. This issue can be fixed by simply
adding "derived-from-or-self" to the IEEE 802.1Q bridge YANG when checking for
ethernetCsmacd in the 'when' statement.

The change provides functional equivalence and also allows other users to
use the Bridge Port definition for proprietary or state-of-the-art interfaces
that are based on ethernetCsmacd. This change would future proof the
IEEE802.1Q bridge YANG model for the cases when there could exist an interface
type derived from ethernetCsmacd by any standards organization. There will
be zero backwards incompatibility problems with this change.
Proposed text
Change:

  augment "/if:interfaces/if:interface" {
    when
      "if:type = 'ianaif:bridge' or if:type ="+
      "'ianaif:ethernetCsmacd' or if:type = 'ianaif:ieee8023adLag'"+
      "or if:type = 'ianaif:ilan'" {

to

 augment "/if:interfaces/if:interface" {
    when
      "derived-from-or-self(if:type,'ianaif:bridge') or "+
      "derived-from-or-self(if:type,'ianaif:ethernetCsmacd') or "+
      "derived-from-or-self(if:type,'ianaif:ieee8023adLag') or "+
      "derived-from-or-self(if:type,'ianaif:ilan')" {

Also we must add the following at the top of the file:

  yang-version "1.1";

(This will allow the usage of "derive-from-or-self".)
Impact on existing networks
YANG upgrade on 'ieee802-dot1q-bridge.yang' will be required with zero backwards incompatibilities. There should not be any impact on existing implementations.
Originator
Name:William ZhaoEmail:william.zhao@siemens.com
Affiliation:Siemens AG
Submitted:2020-12-08