Sometimes the allocated number (Bundle ID, VLAN ID, etc.) is directly used in the name/ID of the entity that the number is allocated for (resource union). Currently, this cannot be done as an atomic operation in RA. First client needs to query RA for available number to use in the name/ID, then use that name/ID as resource union to make the allocation request in RA. This allows for possible contention for allocated numbers.

In order to avoid that, RA shall allow a pattern like aaaa${n}bbbb in the resource union / set in the allocation request, where ${n} shall be replaced with the actual allocated number.