Cisco Unity is a Windows 2000 server-based IP unified messaging system. Cisco Unity scales up to several thousand users and typically is deployed in a central or campus site of an enterprise network with a Cisco CallManager providing the call control.
Note that Cisco Unity and Cisco UE are two different voice mail systems. Cisco UE is a hardware module installed inside the Cisco CME router scaling up to 100 voice mailboxes, whereas Cisco Unity is a separate Windows server platform scaling up to thousands of users.
Cisco Unity's unified messaging capabilities allow you to integrate voice mail, e-mail, and faxes into the same end-user mailbox. The mailbox operation is highly customizable via call handlers. Cisco Unity provides options for integrating with the Microsoft Outlook or Lotus Notes mail architectures. Cisco Unity leverages Active Directory to access your network's user and location directory.
Although Cisco Unity's unified messaging features provide many productivity-enhancing applications such as Cisco Personal Assistant and text-to-speech support, you can also choose to deploy it as a voice mail-only system. Cisco Personal Assistant is a telephony application suite that streamlines communications by helping users manage how and where they can be reached.
Different levels of licensing are available with Cisco Unity for a voice mail-only deployment or a full unified messaging system. Cisco Unity is a sophisticated messaging system with robust failover and networking options. A full discussion of its capabilities is beyond the scope of this book, but you can consult Cisco.com and search for "Cisco Unity" to find more information.
Cisco Unity uses IP as the transport and Skinny Client Control Protocol (SCCP) for call control, appearing to Cisco CME as an IP phone (SCCP) endpoint. Cisco Unity can support a single Cisco CME in a standalone deployment or can be deployed at a central site in your network with multiple Cisco CMEs at remote sites in a centralized voice mail scenario. These architectures are discussed further in the following sections.
Cisco CME is Cisco IOS-based, whereas Cisco Unity is a Windows 2000-based application; therefore, users considering this combination of applications should have a good working knowledge of both operating systems. Cisco Unity uses Microsoft Exchange (5.5, 2000, and 2003) or Lotus Domino mail stores, so familiarity with these technologies is also beneficial.
Standalone Cisco CME System with Cisco Unity
You can connect a standalone Cisco CME with a dedicated Cisco Unity system to provide unified or voice mail services to a single site. Though technically feasible, this is often not a cost-effective way to deploy Cisco Unity. Cisco Unity is an application designed to support large numbers of users, whereas Cisco CME can support only up to 240 users. Figure 11-1 shows how Cisco CME is connected to the Cisco Unity system.
Figure 11-1. Standalone Cisco CME with Cisco Unity Messaging
Although Cisco CME functions as the call control system for taking care of IP phone and PSTN calls, Cisco Unity provides the voice mail services. Cisco Unity communicates with Cisco CME using the SCCP protocol emulating IP phone endpoints.
Multiple Cisco CME Systems with a Centralized Cisco Unity
A much more typical and cost-effective model of using Cisco Unity with Cisco CME is as a centralized messaging system to several remote Cisco CME sites. Figure 11-2 shows multiple Cisco CME systems distributed across several smaller sites connected to a shared, centralized Cisco Unity system. A Cisco CME system at the central site collocated with the Cisco Unity server is required. This Cisco CME relays both voice and Message Waiting Indicator (MWI) to the remote sites.
Figure 11-2. Multiple Cisco CME Systems with Cisco Unity Messaging
A centralized Cisco Unity system offers several advantages:
Configuring Cisco CME for Cisco Unity
Cisco Unity integrates with Cisco CME as SCCP-controlled IP phone endpoints. Each voice mail port on Cisco Unity is configured as an ephone on Cisco CME, and the voice mail pilot number is configured as an ephone-dn that appears on each of the phones (ports).
The Cisco Unity ports register with the Cisco CME router using a voice mail device ID (vm-device-id) such as Cisco UM-VI2. Example 11-1 shows the Cisco CME configuration for connecting to a four-port Cisco Unity voice mail system.
Example 11-1. Cisco CME Configuration for Cisco Unity Ports
router#show running-config telephony-service voicemail 6800 ! ephone-dn 32 number 6800 name "VM Port 1" preference 0 no huntstop ! ephone-dn 33 number 6800 name "VM port 2" preference 1 no huntstop ! ephone-dn 34 number 6800 name "VM port 3" preference 2 no huntstop ! ephone-dn 35 number 6800 preference 3 name "VM Port 4" ephone 5 vm-device-id CiscoUM-VI1 button 1:32 ! ephone 6 vm-device-id CiscoUM-VI2 button 1:33 ! ephone 7 vm-device-id CiscoUM-VI3 button 1:34 ! ephone 8 vm-device-id CiscoUM-VI4 button 1:35
The voicemail 6800 command defines the voice mail pilot number as extension 6800. You can define an ephone-dn for each of the four ports; these definitions control call routing to Cisco Unity. All the ephone-dns have 6800 as the extension and are tagged with preference 0 to preference 3. You need four individual ephone-dns, one per port, to route and deliver four calls to the Cisco Unity system simultaneously. From Cisco CME's point of view, four IP phones have an appearance of extension 6800; therefore, four individual calls to 6800 can be busy at the same time.
The preference and no huntstop designations ensure that the Cisco CME system hunts across the available phones if some of them are busy.
Each of the physical ports is defined as an ephone. To Cisco CME, Cisco Unity ports look like an IP phone, and they register as such. The vm-device-id (for example, Cisco UM-VI2) defined for each ephone must match the device ID configured in the Cisco Unity configuration.
You configure call forwarding to voice mail on your employee's IP phones exactly as you would for Cisco UE, as shown in Example 11-2.
Example 11-2. Call Forwarding to Cisco Unity Voice Mail
router#show running-config ephone-dn 1 number 6001 call-forward busy 6800 call-forward noan 6800 timeout 10
With the configurations given in the previous examples, users on your system can press the messages button on their IP phones to retrieve their voice mail. They can also call the voice mail pilot number 6800 directlyfor example, from the PSTNto access their voice mail.
MWI with Cisco Unity is accomplished via outdial directory numbers (DNs), similar to the architecture with Cisco UE (but not configured in exactly the same way). Cisco CME defines two MWI DNs, one for turning on MWI and another for turning it off. Cisco Unity outdials to one of these numbers to control the phone's MWI state. This configuration is shown in Example 11-3.
Example 11-3. MWI Configuration for Cisco Unity Voice Mail
router#show running-config ephone-dn 30 number 8000 mwi on ! ephone-dn 31 number 8001 mwi off
The extension for which MWI must be turned on or off is derived from the caller ID (the number of the call's originator) provided in the SCCP message received by Cisco CME. Cisco Unity populates the appropriate caller ID in the SCCP message sent to Cisco CME when it initiates the call to one of the MWI DNs. Cisco CME then uses this caller ID to determine which IP phone on the system should receive MWI and sends a separate SCCP message to the phone(s) to turn its MWI on or off.
The MWI configuration for Cisco Unity differs from that of Cisco UE in two important ways:
Cisco Unity physically integrates only with the single Cisco CME that is collocated with it. All the Cisco Unity ports register with this Cisco CME system. To get Cisco Unity to support voice mail for users of Cisco CME systems at remote sites, certain information must be relayed via the central Cisco CME that is physically connected to Cisco Unity.
Calls to Cisco Unity to leave or retrieve messages can be freely routed across your network between the sites based on your dial plan. The relay mechanism comes into play only for getting MWI notifications to an IP phone at a remote site.
Cisco CME contains an MWI relay mechanism that is configured at the central Cisco CME (the one with the MWI DNs that Cisco Unity dials). The central Cisco CME cannot send an SCCP message directly to an IP phone that is registered with a different Cisco CME system. Instead, it uses a Session Initiation Protocol (SIP) subscribe/notify mechanism to notify the remote Cisco CME of an MWI change. The remote Cisco CME system (where the IP phone is registered) then sends an SCCP message to the phone to change its MWI state. This configuration is shown in Figure 11-3.
Figure 11-3. MWI Relay with Cisco Unity
The MWI relay configuration at the central Cisco CME (site A) is shown in Example 11-4.
Example 11-4. MWI Relay Configuration for the Central Site
router#show running-config telephony-service ip source-address 10.10.10.1 mwi relay mwi expires 99999 voicemail 6800
The mwi relay command lets the Cisco CME router relay the MWI information to a remote IP phone. The mwi expires command sets the expiry timer for the SIP subscribe/notify registration.
The MWI relay configuration at one of the remote Cisco CME sites (for example, site B) is shown in Example 11-5.
Example 11-5. MWI Relay Configuration for a Remote Site
router#show running-config telephony-service ip source-address 22.214.171.124 mwi sip-server 10.10.10.1 transport tcp ! ephone-dn 1 number 2000 mwi sip call-forward noan 6800 timeout 10 call-forward busy 6800 ! dial-peer voice 101 voip destination-pattern 6800 session target ipv4:10.10.10.1 codec g711ulaw dtmf-relay h245-alphanumeric no vad
The mwi sip-server command instructs the Cisco CME at site B to subscribe to the SIP server on Cisco CME site A (IP address 10.10.10.1 in Example 11-4). Each of the ephone-dns at sites B and C must contain the mwi sip command to ensure that the controlling Cisco CME system knows that this phone's MWI is controlled via a SIP notification from another site. As soon as the configuration is entered, the show mwi relay clients command at the site A Cisco CME shows all the extensions subscribed to the Cisco CME site A SIP server.
The dial peer shown in Example 11-5 ensures that users at site B can dial 6800 (the voice mail pilot number). The call is routed across VoIP to site A, where the Cisco Unity system is located.
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