See the following sections:
If your organization has more users than a single Cisco Unity Connection server or cluster pair can support, you can use Digital Networking to internetwork multiple Connection systems. Cisco Unity Connection 7.x is the first Connection release to support Digital Networking. Connection 7.0 supports digitally networking a maximum of five systems, where a system is either a standalone Connection server or a Connection cluster pair (see Figure 4-1). Connection 7.1 and later support digitally networking a maximum of ten systems.
Digital Networking is not supported for use with Cisco Unified Communications Manager Business Edition.
Figure 4-1 A Cisco Unity Connection 7.x Digital Network Consisting of Five Connection Systems
Digitally networked Connection systems automatically exchange directory information, so that a user on one Connection system can dial out to or address messages to a user on any other system by name or extension, provided that the target user is reachable in the search scope of the originating user. The networked systems function as though they share a single directory. Users do not need to know where another user is located; they need only the name or extension number to address a message to any user or system distribution list in the directory.
Because digitally networked systems use SMTP transport for both directory replication and message transport, Connection locations can be deployed across geographic boundaries. Each server that is joined to the Digital Network must be able to access all other servers on the Digital Network directly through TCP/IP port 25, or SMTP messages must be routable among the servers through an SMTP smart host.
If your Digital Network includes a Connection cluster, you must have a smart host available to resolve the SMTP domain of the cluster to both the publisher and subscriber servers in order for message traffic to reach the cluster subscriber server in the event that the publisher server is down.
In a Digital Network, each Connection object is created and homed on a single Connection system, known as a Connection location. An object can only be modified or deleted on the Connection system where it was created. Each location has its own directory of users and other objects, and replicates a subset of these objects and their properties to other locations.
The following objects are replicated in a Connection Digital Network:
•Contacts (system and VPIM)
•System distribution lists (including membership)
•Locations (Connection and VPIM)
•Recorded voice names
The total number of combined users, system contacts, and personal contacts in a Digital Network cannot exceed 50,000 in Connection 7.x.
You can also optionally deploy additional cross-server features between systems in a Digital Network. Cross-server logon allows all users to dial the same number when calling from outside the organization to log on to Connection, regardless of which Connection server they are homed on. Cross-server transfer enables calls from the automated attendant of one Connection system to be transferred to a user on another networked Connection system, according to the call transfer and screening settings of the called user. When you enable cross-server transfer, cross-server live reply is also enabled, allowing users to return calls to message senders who are users on other networked Connection systems, according to the call transfer and screening settings of the called user.
For more information on Digital Networking, design considerations, and configuration details, see the "Using Digital Networking" chapter of the System Administration Guide for Cisco Unity Connection Release 7.x.
Cisco Unity Connection 7.x supports the Voice Profile for Internet Mail (VPIM) protocol, which is an industry standard that allows different voice messaging systems to exchange voice and text messages over the Internet or any TCP/IP network. VPIM is based on the Simple Mail Transfer Protocol (SMTP) and the Multi-Purpose Internet Mail Extension (MIME) protocols.
VPIM Networking is supported for use with Cisco Unified Communications Manager Business Edition.
VPIM Networking is a licensed feature. Connection supports internetworking with voice messaging systems that support the VPIM version 2 protocol, as defined in Internet RFC 3801. For a list of messaging systems that are supported by Connection for VPIM networking, see the "Requirements for VPIM Networking" section in the System Requirements for Cisco Unity Connection Release 7.x.
Connection 7.x supports up to 10 VPIM locations and 15,000 VPIM contacts in the Connection directory. These same limits apply either to the directory of a single Connection server or cluster pair, or to the global directory in a Digital Network. If you deploy both VPIM and Digital Networking, we recommend that you designate a single Connection location on the Digital Network as the bridgehead to handle the configuration of VPIM locations and contacts. Managing these objects from a single location simplifies maintenance tasks and avoids potential overlaps in contact information that could cause confusion to users when they attempt to address messages.
For more information on VPIM Networking, design considerations, and configuration details, see the "Using VPIM Networking" chapter of the System Administration Guide for Cisco Unity Connection Release 7.x.