CCNA Voice: Unified Communications at a Glance

Unified Communications Pieces

Unified Communications Products

Core products:

• Cisco Unified Communications Manager Express
• Cisco Unified Communications Manager
• Cisco Unity Connection
• Cisco Unified Presence

Other products include Cisco Unified Contact Center Enterprise/Express, Cisco Unified MeetingPlace, etc

Cisco Unified Communications Manager Express

CME was designed for ISR G2 Routers, ISR G1 routers with proper IOS and hardware can also support CME 8.X

Key Features of CME:

• Call control device, handles signaling, call routing, call features
• CLI or GUI based configuration using CCP
• Local telephone directory
• CTI support for application integration
• Trunk to other VOIP systems (ie, CUCM)
• Cisco Unity Express Module direct integration with network module

CME controls almost all actions performed with Cisco IP Phones using SCCP or SIP

As user inputs to the phone, SCCP or SIP messages are sent between CME and IP Phone to determine what is happening

After call setup, RTP stream is created between two endpoints and CME is no longer involved

For calls to the PSTN, CME acts as the voice gateway and transcodes analog to digital signal using DSP/PVDM modules. During the call CME transcodes between PSTN and IP phone and can not be removed from call flow

Cisco Unity Express

Integrated hardware module for CME router to provide voicemail services. Either comes as ISM or SM. ISM is internal to CME router and uses flash memory for storage. SM is external and uses a hard drive for storage. ISM/SM replace CUE AIM and NM

CUE runs its own independent Linux-based OS which is accessible from CME router after install

Key features of CUE:

• Voicemail
• Auto-attendant for dial-by-name, basic operator/menu capabilities
• IVR system with basic menu tree system, more features than Auto-attendant
• Native T.37 Fax Processing, can receive faxes and process to user's mailbox as TIFF attachment
• SRSV sets CUE to act as backup voicemail if enterprise Cisco Unity Connection is inaccessible
• Standards-based SIP protocol signaling between CUE and CME

Cisco Unified Communications Manager

CUCM is the call processing director of a Unified Communications solution

Key Features of CUCM:

• Complete audio/visual telephony support
• Appliance-based, meaning the operating system is secured/inaccessible 
• Redundant servers
• Intercluster/voice gateway control/communications
• Disaster Recovery System
• VMWare virtualization support
• LDAP/Active Directory integration support

CUCM Database Replication

CUCM IBM Informix Database includes info such as dirctory numbers, route plan, hunt groups, etc which is replicated to all servers in cluster

CUCM Runtime (real-time) data is replicated to other cluster members using Cisco proprietary Intracluster Communication Signaling (ICSS)

All servers in CUCM cluster form TCP connecions to each other for ICSS on port 8002- 8004 and keep each other informed

CUCM Publisher holds master copy of Informix database, changes to the database happen on the Publisher and are replicated to subscribers

Each cluster supports one Publisher and up to eight Subscribers. Publisher maintains database and  serves TFTP requests and Subscribers handle phone registration and call control

If Publisher fails, changes can not be made to database, excepting user-facing features such as call forwarding and DND button, etc. Subscriber writes local copy of change and replicates to other subscribers until Publisher returns online

Cisco Unity Connection

Cisco Unity Connection is an enterprise, appliance-based voice-mail solution similar to CUCM

Key features of CUC:

• Appliance-based: Stable, hardened, appliance-based OS
• 20,000 mailboxes per server
• Remote access to voicemail via email, browser, IM and phone
• LDAP/Active Directory integration
• Microsoft Exchange supported for calendar integration, text-to-speech, etc
• Voice Profile for Internet Mail: Standard which allows other voicemail servers to integrate for exchange of voicemail and other messages
• Active/Active HA cluster with Publisher/Subscriber and Informix DB allows doubling of voicemail ports and mailboxes

If one of HA cluster fails, half the voicemail ports and mailboxes are inaccessible

CUC is able to integrate with other call control systems such as PBX and so does not have close integration with CUCM. CUC is set as an outside system that CUCM communicates with using SIP/SCCP

CUCM to CUC Call Flow:

1. Incoming voice call hits CUCM from PSTN VG or internal call
2. CUCM routes call to approriate IP phone
3. If call is not answered, CUCM forwards call to Voicemail pilot extension
4. CUCM transfers call to CUC with original extension in SCCP/SIP signaling which CUC uses to find appropriate mailbox
5. After VM is recorded, CUC calls MWI extension on CUCM to toggle light on IP phone 

All communication takes place using voicemail ports
CUC can also integrate with CME

Cisco Unified Presence

CUP is used to track availability of a user and provide enterprise IM capability

Key features of CUP:

• Enterprise IM using Jabber XCP
• Logging functionality for all types of IM communication
• Can connect to other domains such as Google Talk or WebEx
• XCP allows CUP to extend to almost any part of the network, for file sharing, app sharing, videoconferencing. XCP integrates with directory services, databases, web
• CUP application integration supports IPSec or TLS encryption to secure communication

Unified Personal Communicator

Software application that combines softphone, IM client, employee directory, video/web conferencing. Allows tracking of user status and virtual meetings

CUPC uses LDAP for login to the client and a CUPS server on the back end