CUCM Deployment Models

--> CUCM can be deployed in following methods,

1) SINGLE SITE DEPLOYMENT SOLUTION

--> A Single CUCM or CUCM cluster located at a single site with no telephony services provided over a WAN.

--> All CUCM servers, applications, and digital signal processor (DSP) resources are located in the same physical location.

--> Each cluster supports a maximum of 40,000 IP phones. If there is a need to deploy more than 40,000 IP phones in a single-site configuration, multiple clusters can be implemented inside a LAN or within a MAN and connected through intercluster trunks.

--> Single-site deployment allows Calls between sites will be routed over the PSTN ( No IP Telephony over WAN).

--> Extra provisioning of WAN bandwidth is not needed. Dial plans are also easier to implement.

--> There are no service issues in the event of an IP WAN failure or insufficient bandwidth, and there is no loss of call-processing service or functionality.

--> Recommended for medium-sized businesses and government operations that reside at one site and that need basic call processing, some contact center capabilities, and basic messaging and conferencing.

2) MULTISITE DEPLOYMENT WITH CENTRALIZED SOLUTION

--> A Single CUCM or CUCM cluster located at a single site with telephony services provided over a WAN.

--> The remote sites rely on the centralized CUCM cluster to manage their call processing.

--> Applications such as voice mail and interactive voice response systems are typically centralized as well to reduce the overall costs of administration and maintenance.

--> In case of CUCM is down at Centralized Site, IP phones in Remote site uses CME to forward the voice traffic using PSTN link.

--> Call Admission Control (CAC) is used to limit the number of calls between the sites.

--> Recommended for businesses such as banks, which include a corporate headquarters and many local or regional offices.

3) MULTISITE DEPLOYMENT WITH DECENTRALIZED SOLUTION

--> A Single CUCM or CUCM cluster located at every single site with telephony services provided over a WAN.

--> An IP WAN carries voice traffic between the distributed clusters.

--> Call admission control is achieved through Enhanced Locations CAC or RSVP.

--> Maximum utilization of available bandwidth is possible by allowing voice traffic to share the IP WAN with other types of traffic.

--> Recommended for business operations that consist of multiple sites in various regions. Such operations include technology, manufacturing, transportation, and distribution and logistics companies.