You have registered one non-Cisco IP phone with UCM. Every other IP phone on the network is a Cisco IP
phone.
Which of the following statements is most likely true?
A.
Only one H.323 endpoint is registered with UCM.
B.
Only one SCCP endpoint is registered with UCM.
C.
Only one SIP endpoint is registered with UCM.
D.
Only one MGCP endpoint is registered with UCM.
Explanation:
Most likely, only one Session Initiation Protocol (SIP) endpoint is registered with Cisco Unified Communications
Manager (UCM) if you have registered one non-Cisco IP phone with UCM and every other IP phone on the
network is a Cisco IP phone. SIP is an Internet Engineering Task Force (IETF)standard call signaling protocol
that is supported by a wide variety of IP telephony vendors. A call signaling protocol is responsible for the setup,
maintenance, and teardown of a voice call. For example, call signaling protocols can detect and report when aphone is off-hook.
SIP uses a text-based signaling method, which is easier to understand and troubleshoot than the binary method
used by other protocols, such as Skinny Client Control Protocol (SCCP) and H.323. For example, SIP uses
text-based INVITE requests and ACK requests to invite a user to participate in a call and to acknowledge that
user’s response to the INVITE, respectively. Although SIP is typically used as a peer-to-peer call signaling
protocol, it can also operate in client/server mode. SIP is most commonly used by Internet telephony service
providers (ITSPs). Therefore, many non-Cisco IP phones and video phones are SIP phones.
More than one SCCP endpoint would be registered with UCM in this scenario, where you registered only one
non-Cisco IP phone with UCM and every other IP phone on the network is a Cisco IP phone. By default, Cisco
IP phones use SCCP, which is a Cisco-proprietary client/server call signaling protocol intended to be an
alternative to H.323. Although a few third-party IP phones support SCCP, SIP is more widely supported on nonCisco IP phones. SIP can be supported by Cisco IP phones with a firmware replacement.
Neither Cisco IP phones nor third-party IP phones typically use Media Gateway Control Protocol (MGCP).
MGCP is a client/server call signaling protocol. MGCP is an IETF-standard protocol that can be used on some
Cisco IP phones with a firmware replacement.
Neither Cisco IP phones nor third-party IP phones typically use H.323. H.323 is an International
Telecommunication Union (ITU)standard, peer-to-peer call signaling protocol. Peer-to-peer call signaling
protocols do not require a call processing platform, because the voice gateways provide their own call signaling
and call routing. Therefore, you would be more likely to register a non-Cisco SIP IP phone than an H.323 IP
phone with UCM. Although UCM supports H.323, Cisco IP phones do not, because H.323 consumes a large
amount of processor and memory resources.Cisco: Chap 6: SIP Messages and Compliance Information for Cisco VoIP Infrastructure Solution for SIP:
Requests