Which statement about a virtual SNR DN-configured Cisco Unified Communications Manager
Express-enabled Cisco IOS router is true?

A.
Virtual SNR DN supports either SCCP or SIP IP phone DNs.

B.
A virtual SNR DN is a DN that is associated with multiple registered IP phones.

C.
Calls in progress can be pulled back from the phone that is associated with the virtual SNR DN.

D.
The SNR feature can only be invoked if the virtual SNR DN is associated with at least one
registered IP phone.

E.
A call that arrived before a virtual SNR DN is associated with a registered phone, and still exists
after association is made, but cannot be answered from the phone.

Explanation:
Virtual SNR DN only supports Cisco Unified SCCP IP phone DNs.
Virtual SNR DN provides no mid-call support.
Mid-calls are either of the following:
– Calls that arrive before the DN is associated with a registered phone and is still present after the
DN is associated with the phone.
– Calls that arrive for a registered DN that changes state from registered to virtual and back to
registered.
Mid-calls cannot be pulled back, answered, or terminated from the phone associated with the DN.
State of the virtual DN transitions from ringing to hold or remains on hold as a registered DN.

http://www.cisco.com/c/en/us/td/docs/voice_ip_comm/cucme/admin/configuration/guide/cmead
m/cmesnr.html