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?
- Only one H.323 endpoint is registered with UCM.
- Only one SCCP endpoint is registered with UCM.
- Only one SIP endpoint is registered with UCM.
- Only one MGCP endpoint is registered with UCM.
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 a phone 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 non-Cisco 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.