[netmod] Mask tag Usage in draft-ietf-netmod-node-tags

[Qin Wu <[e-mail]>]

Hi, All:
In IETF 114, one issue we discussed for draft-ietf-netmod-node-tags is about mask-tag usage, we use mask-tag to remove the tag.
actually we have two options to remove the tag, one is using edit-data protocol operation to delete the tag,
the other is to use mask-tag to remove tag. so the question when to use mask-tag to remove tag and when to use edit-data operation to delete the tag, what is their priority.
Since the tag can either schema level tag or instance level tag, the original proposal is only using mask-tag to remove schema level tag, which is static tag, the tag will disappear
from operational datastore, but it still exists in the model schema.
But for instance level tag, it is actually user configured tag, I think we can skip to use mask-tag, just use edit-data operation to add tag and remove tag. The reason to skip to use mask tag, becos, the mask tag is only applied to schema level tag or static tag.
Here is the proposed changes to section 7:
OLD TEXT:
"
leaf-list masked-tag {
   type tags:tag;
   description
   "The list of tags that should not be associated with the
   node within the YANG module. The user can remove
   (mask) tags from the operational state datastore by
   adding them to this list. It is not an error to add tags
   to this list that are not associated with the data
   node within YANG  module, but they have no operational
   effect.";
"
NEW TEXT:
"
leaf-list masked-tag {
   type tags:tag;
   description
   "The list of tags that should not be associated with the
   node within the YANG module. The user can remove
   (mask) tags from the operational state datastore by
   adding them to this list.  It is not an error to add tags
   to this list that are not associated with the data
   node within YANG  module, but they have no operational
   effect. Note that the tags described here are limited to system tags
    not applied to user configured tags. ";
"
OLD TEXT:
"
    The 'operational' state view of this list is
    constructed using the following steps:

    1) System tags (i.e., tags of 'system' origin) are added.
    2) User configured tags (i.e., tags of 'intended' origin) are added.
    3) Any tag that is equal to a masked-tag is removed.";
"
NEW TEXT:
"
    The 'operational' state view of this list is
    constructed using the following steps:

    1) System tags (i.e., tags of 'system' origin) are added.
    2) User configured tags (i.e., tags of 'intended' origin) are added.
    3) Any system tag that is equal to a masked-tag is removed.
         4) User configured tags can be removed using standard protocol operation.
         ";
"

-Qin