CUCM Signaling and Media Paths

For hit set up, teardown and advantageous assistance work, CUCM utilizes SIP or SCCP to speak with Cisco IP Phones. Utilize the Real-Time Transport Protocol (RTP) to convey sound, after a call has been made, media trade happens straightforwardly between the Cisco IP Phones across the IP organization. After the call has been set up, CUCM isn't associated with a call. In the event that during the consider period the CUCM worker were unplugged, clients could never see it except if they were attempting to utilize a component on the telephone. CUCM is just associated with the setting up, teardown and usefulness of the call. In the event that the CUCM worker that introduced the call was down, end clients would see a message on the LCD screen of the IP telephone that read "CM Down, Features Disabled. " 

Cisco essential call 

Toward the beginning of a call, an IP telephone client A gathers the handset and makes an impression on CUCM, which discloses to cisco callmanager CUCM it has gone free. CUCM answers this upgrade by noting a message telling that the gadget plays a dial-tone record put away in the telephone's blaze memory. The client tunes in to the dial tone on telephone An and starts to dial telephone B. SCCP telephones send their numbers to CUCM when they are squeezed, while SIP telephones send dialed numbers of course into a solitary message (flagging). Taste telephones have alternatives for utilizing SCCP (keypad increase language[ KPML] and dial rules) like SCCP telephones. Advanced examination of the dialed digits is completed by CUCM. At the point when a match is recognized, CUCM courses the call as indicated by its arrangement. In the event that a match isn't found in CUCM, the guest will get a reorder tone. 

CUCM reports the ringback calling party so the client hears the ringback tone at Phone A. CUCM likewise flags the ringdown tone to the objective telephone. Additional data on the calls and the gathering name and number are given to the phones. Telephone A presentations the name and number of the objective gadget and Phone B shows the name and number of the calling party. 

At the point when the telephone B client acknowledges the call, CUCM makes an impression on the gadget to illuminate the IPv4 attachment regarding data that ought to be contained for the span of a call( IPv4 address and port number). The RTP media way opens between the two telephones straightforwardly. 

Cisco IP Telephones don't need further correspondence with CUCM until a component like a call move, a call conferencing or call end is conjured by one or the other telephone.