You administer a UCM network of 500 IP phones.
Your supervisor asks you to add 101 new IP phones to the network before the end of the workday.
Which of the following does Cisco recommend you do?

A.
Add a second UCM server to the cluster.

B.
Add the phones by using the BAT.

C.
Enable auto-registration in UCM.

D.
Provision the IP phones manually in UCM.

Explanation:
Cisco recommends that you use the Bulk Administration Tool (BAT) to add more than 100 new IP phones to a
Unified Communications Manager (UCM) network. There are three ways to add IP phones to a UCM database:
by configuring auto-registration, by using the BAT, and by manually provisioning the IP phones in the UCM
administrative graphical user interface (GUI). Both auto-registration and the BAT provide a means of adding
many phones to the database simultaneously. However, Cisco does not recommend using the auto-registration
method of adding IP phones if you need to add 101 or more IP phones.
You do not need to provision the IP phones manually in UCM. Although you can manually add an IP phone to a
UCM database, adding 101 new IP phones by using manual provisioning would require more administrative
effort than by using auto-registration or the BAT. When you are manually provisioning an IP phone in UCM, you
must fill in the MAC Address field, the Device Pool field, the Phone Button Template field, and the Device
Security Profile field. In this scenario, your supervisor has asked you to add 101 IP phones to the network
before the end of the workday. Therefore, you should not manually provision the IP phones.
You do not need to enable auto-registration in UCM. Auto-registration enables UCM to automatically add new
IP phones to the UCM database. When a new IP phone is connected to the network, UCM will automatically
assign an unused directory number (dn) to the IP phone from a pool of available dn numbers. However, autoregistration is a security risk because rogue devices can be connected to the network and registered with UCM
by using auto-registration. In addition, you could accidentally register a valid IP phone with a dn from the wrong
dn pool if you leave auto-registration enabled after you have completed an auto-registration process. Therefore,
Cisco recommends that you enable auto-registration only for short periods of time, such as when you need toadd fewer than 100 IP phones to the network.
You do not need to add a second UCM server to the cluster. UCM supports a maximum of 7,500 devices as a
standalone server and a maximum of 30,000 IP phones per UCM cluster. In this scenario, you administer a
network of 500 IP phones. In addition, you are adding only 101 new IP phones, which brings the total number of
IP phones to 601.
Cisco: Auto-registration: Understanding Auto-registration