The YANG structure shown defines a leaf IPPeer that can be either an IPv4 address or an IPv6 address. The third JSON example correctly represents this union type by using an array with both possible types included:
"IPPeer": [
"10.1.1.1",
"2001:db::1"
]
}
This correctly reflects the YANG definition, where IPPeer can be either type specified in the union.
References:
* YANG - Data Modeling Language
* Cisco YANG Models