If you choose not use the 802.1Q tag (VLANid) of the master VLAN, or you have an untagged master VLAN, you must create a domain ID before you can enable the ESRP domain. For more information about ESRP domains and the ESRP domain ID, see ESRP Domains.
The number parameter specifies the number of the domain ID. The user-configured ID range is 4096 through 65,535.