Which two statements about the Peer Firmware Sharing option for IP phone firmware distribution
are true? (Choose two.)

A.
This option uses a parent-child hierarchy in which a firmware image is downloaded by a parent
phone to up to three directly associated child phones.

B.
This option must be enabled on Cisco Unified Communications Manager service parameters for
Cisco TFTP.

C.
This option mandates that the parent phone and child phones be identical, selected phone
models.

D.
This option allows firmware transfers between phones in different subnets, as long as the roundtrip delay is less than 5 milliseconds.

E.
This option uses a parent-child hierarchy that must be manually defined by the Cisco Unified
Communications Manager administrator.

F.
This option allows falling back to the TFTP server in the Cisco Unified Communications Manager
cluster.

Explanation:
Peer Firmware Sharing works by setting up a parent-child hierarchy of the phones in which a
firmware image is downloaded by the parent phone to a child phone. The advantage of using Peer
Firmware Sharing is that instead of all phones individually retrieving a software image, they pass the
image along from one phone to another phone on the same subnet.
Advantage of PFS:
Hierarchy is automatic
One download per phone model on a subnet
Uses TCP
Fails back to TFTP
Speeds up LAN upgrades
Reduces TFTP CPU load during upgrade