[netmod] RFC 6991 definition of ipv4-address

["Rob Wilton (rwilton)" <[e-mail]>]

Hi,

Putting aside the discussion about whether we should be changing the use of ip-address vs ip-address-no-zone in existing YANG modules for the moment, I believe that the current ipv4-address|ipv6-address|ip-address definitions is either wrong, or unhelpful for two reasons:

(1) It specifies that If a zone index is not present, then the default zone of the device will be used.

Specifically, I interpret this as, if a YANG module uses the type ip|ipv4|ipv6|-address when the associated interface is provided via context (e.g., either a leaf in a parent key, or a sibling interface-ref leaf) then if the device returns a link-local IP address without a zone then it must be associated with the default zone of the device and not the associated interface.  I.e., the only way that devices return the correct value in this case would be to always return the zone information (in ifindex format) for all link-local addresses.

(2) The ipv4|v6-address-types specify that the canonical format for zones is the numerical format.  I.e., using the ifindex for an interface which isn't really meaningful or helpful for clients interacting with a device via YANG, and which may have no idea what the associated SNMP IfIndex is.  It seems to me that the canonical format for zones should be the interface name, not the IfIndex.

I would be interested to understand whether there is any WG consensus that these are valid problems with how ip-address (and friends) is defined both for implementations that include zone information and also those that don't.

Regards,
Rob

// As a contributor