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Table Of Contents
Cisco Unified Messaging Gateway Overview
E-SRST and SRSV Licenses and When to Deploy Them
Enhanced Survivable Remote Site Telephony (E-SRST)
Survivable Remote Site Voicemail (SRSV)
Limitations for Interoperating with Cisco Unified Communications Manager
Voicemail Limitations and Restrictions
Network Address Translation (NAT) Restrictions
High Availability Restrictions
Voicemail Backup and Restore Limitations
Live Record and Live Reply Limitations
Combined SRSV and E-SRST on the Same Site
Voice Profile for Internet Mail (VPIM) Networking
Managing a Network of Cisco UMG VPIM Nodes
Cisco Unified Messaging Gateway Overview
Last updated: December 2, 2010
This chapter provides an overview of Cisco Unified Messaging Gateway and the features supported. This chapter covers the following topics:
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Enhanced Survivable Remote Site Telephony (E-SRST)
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Introduction
Cisco Unified Messaging Gateway 8.5 is an application that resides on an enhanced network module (NME) or Services Ready Engine service module (SM-SRE). The module plugs into a host Cisco router running Cisco IOS software. All models are shipped from the factory with the software preinstalled.
Cisco Unified Messaging Gateway (UMG) release 8.5 is supported on the following modules:
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For more information about hardware support requirements, see the Release Notes for Cisco Unified Messaging Gateway.
Cisco UMG supports the following features:
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For information about how each feature is deployed, see the following sections. For information about deployment scenarios combining E-SRST and SRSV on a site, see the "Combined SRSV and E-SRST on the Same Site" section. For information on the different options for deploying E-SRST and SRSV licenses, see the "E-SRST and SRSV Licenses and When to Deploy Them" section.
Feature licenses for E-SRST, SRSV, and VPIM are available in increments of 25 sites or nodes each. For example, if you are deploying 25 SRSV sites, then you must purchase one SRSV feature license. If you are deploying 30 SRSV sites, then you must purchase two SRSV feature licenses. For more information about feature licenses, see the Release Notes for Cisco Unified Messaging Gateway.
E-SRST and SRSV Licenses and When to Deploy Them
The E-SRST and SRSV features can be deployed separately or together on a given site. You can configure a site for either feature or both depending on your needs. For each feature deployed at each site, a feature license must be purchased.
The supported call control methods on a branch site are:
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CUCME-as-SRST is also known as the SRST Fallback Mode feature on Cisco Unified Communications Manager Express (CUCME).
E-SRST is not required if you are using original SRST and are not provisioning advanced telephony features for use in survivable mode. E-SRST is recommended if you plan to use advanced Cisco Unified Communications Manager (CUCM) telephony features in survivable mode.
Table 1 summarizes the different options for enabling E-SRST and/or SRSV on a given site.
Table 1 Cisco UMG 8.5 Features and Call Control Options on a Branch Site
E-SRST only
CUCME-as-SRST
Provisioned on central CUCM, automatically downloaded to the branch site.
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SRSV only
SRST
Not Applicable3
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SRSV only
CUCME-as-SRST
Manually provisioned on the branch site.
Yes
E-SRST and SRSV
CUCME-as-SRST
Provisioned on central CUCM, automatically downloaded to the branch site.
Yes
1 Feature license must be installed on a per-site basis for provisioning to take place.
2 Requires SRSV-CUE software to be installed on the branch voicemail server.
3 Original SRST does not support advanced telephony features.
For more detailed information about each feature, see the Enhanced Survivable Remote Site Telephony (E-SRST) below and the "Survivable Remote Site Voicemail (SRSV)" section.
Enhanced Survivable Remote Site Telephony (E-SRST)
Enhanced Survivable Remote Site Telephony (E-SRST) is supported in Cisco UMG 8.5 and later versions. The E-SRST functionality requires the installation of E-SRST licenses, with each license supporting up to 25 sites per license. The E-SRST feature can be deployed separately or combined on a given site with Survivable Remote Site Voicemail (SRSV). See also the "Combined SRSV and E-SRST on the Same Site" section.
E-SRST provides an integrated solution that supports advanced CUCME-as-SRST telephony features such as hunt groups and pick-up groups, but reduces the complex and manual configuration required at the branch site.
If deploying E-SRST, the UMG system at the central office collects information from CUCM, generates the complex configuration information required for advanced features such as hunt groups and pick-up groups, and then distributes this configuration information to the branch office sites. In the event of a WAN outage, when the CUCME-as-SRST service running on the branch office routers takes over call processing, it leverages the configuration provisioned by the central office UMG system to provide enhanced SRST services at the branch.
Figure 1 shows the supported topology model for E-SRST on a branch site. In this example, SRSV is not deployed at the branch site.
Figure 1 E-SRST Only Topology
E-SRST provides automated remote site provisioning of the following advanced telephony features in survivable mode by gathering the information from CUCM:
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E-SRST enables an administrator to set up provisioning schedules for defining when and how often to fetch configuration information from CUCM and provision the branch office CUCME-as-SRST routers. The administrator can also do an on-demand provisioning to synchronize a specific CUCME-as-SRST router with the CUCM information.
The CUCME-as-SRST configuration in the E-SRST solution enables a phone in SRST mode to operate similarly to when the system is in normal CUCM mode. The look and feel of the phone displays and softkeys in SRST mode are similar to those in normal CUCM mode.
For more information about CUCME, see the documentation at: http://www.cisco.com/en/US/partner/products/sw/voicesw/ps4625/tsd_products_support_series_home.html.
E-SRST Limitations
This section describes the limitations for E-SRST.
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Survivable Remote Site Voicemail (SRSV)
This section describes the Survivable Remote Site Voicemail (SRSV) solution and it covers the following topics:
Introduction to SRSV
Survivable Remote Site Voicemail (SRSV) is supported in Cisco UMG 8.0 and later versions. The SRSV functionality requires the installation of SRSV licenses, with each license supporting up to 25 nodes per license. The SRSV feature can be deployed separately on a given site or combined with Enhanced Survivable Remote Site Telephony (E-SRST).
The SRSV solution requires the following two components:
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The SRSV-UMG component is deployed at the central office alongside Cisco Unified Communications Manager (CUCM) and Cisco Unity Connection (CUC). The SRSV-UMG component is deployed using Cisco Unified Messaging Gateway software with SRSV licenses installed. For product versions compatible with Cisco SRSV-UMG, see the Release Notes for Cisco Unified Messaging Gateway.
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The SRSV-CUE component is deployed at the branch office alongside Cisco Unified Communications Manager Express (CUCME) or Cisco Unified Survivable Remote Site Telephony (SRST). Cisco Unified SRSV-CUE is a separate orderable product, and different hardware and software requirements apply. For more information, see the Release Notes for Cisco Unified Survivable Remote Site Voicemail and the Installation and Administration Guide for Cisco Unified Survivable Remote Site Voicemail.
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The standalone SRSV solution introduced in Cisco Unified Messaging Gateway 8.0 uses either original SRST or CUCME-as-SRST. Original SRST requires simple, very limited provisioning on the remote office router, but provides very limited features to support basic phone calls. CUCME-as-SRST, also known as SRST Fallback Mode, provides advanced telephony features such as hunt groups and pick-up groups that are not available with original SRST, but it requires more complex and manual provisioning on the branch routers. For information about configuring CUCME-as-SRST, see the "Configuring SRST Fallback Mode" chapter in the Cisco Unified Communications Manager Express System Administrator Guide.
The Enhanced Survivable Remote Site Telephony (E-SRST) feature introduced in Cisco Unified Messaging Gateway 8.5 reduces the manual provisioning required for selected advanced telephony features supported by CUCME-as-SRST. For more information, see the "Enhanced Survivable Remote Site Telephony (E-SRST)" section.
When deployed and provisioned, the SRSV-CUE system sits idle in the branch office, ready to receive calls from the SRST system (either original SRST or CUCME-as-SRST). The SRST component (provisioned by Cisco Unified Communications Manager), also sits idle, waiting for IP phones to register with it. When a WAN outage occurs, the branch office IP phones that are registered to the central office CUCM detect the loss of connectivity and re-home to the SRST. Incoming PSTN calls to the branch office are then handled by the SRST. For calls that are either no-answer or reach a busy line, the SRST can forward to the SRSV system. As a result, the branch office voicemail is supported during WAN outages when the central office voicemail system is unreachable.
When the WAN connection returns, the IP phones automatically re-home to the central office CUCM. Call handling is then managed by CUCM, and no-answer / busy calls are forwarded to the central office CUC voicemail system.
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Supported SRSV Topologies
Several SRSV topologies are supported beginning with Cisco UMG 8.0. Depending on the configuration, you can have either original SRST or CUCME-as-SRST (also known as SRST Fallback Mode) deployed at the branch site. Note that if you are running SRST at the branch site, you cannot also deploy the E-SRST feature. See Table 1 for the supported combinations of features.
Figure 2 shows a topology in which SRST is deployed at the branch site. If the WAN or PSTN goes down, the SRSV-CUE at the branch site provides limited voicemail support in failover mode.
Figure 2 SRSV Topology Using SRST at the Branch Site
Figure 3 shows a topology where CUCME-as-SRST (also known as SRST Fallback Mode) is providing call control at the branch site.
Figure 3 SRSV Topology Using CUCME-as-SRST at the Branch Site
Figure 4 shows a topology where multiple CUCME-as-SRST and SRSV-CUE devices are paired for load balancing at the survivable branch site. In this scenario, the administrator uses CUCM to divide the branch users between CUCME-SRST-1 and CUCME-SRST-2. The Cisco UMG learns about which phones are assigned to each device, and then pulls the relevant voicemail configuration from Cisco Unity Connection at the central site, and then pushes the appropriate configuration to SRSV-CUE-1 and SRSV-CUE-2 at the branch site. In the event of a WAN failure, each SRSV-CUE device will handle calls directed to it from the paired CUCME-as-SRST device.
Figure 4 SRSV Topology with Multiple CUCME-as-SRST Devices Load Balanced at Remote Site
SRSV Limitations
This section describes the limitations for the SRSV solution.
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Limitations for Interoperating with Cisco Unified Communications Manager
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Voicemail Limitations and Restrictions
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Auto Attendant Limitations
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Network Address Translation (NAT) Restrictions
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High Availability Restrictions
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Voicemail Backup and Restore Limitations
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Mailbox Limitations
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Live Record and Live Reply Limitations
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Distribution Lists
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Combined SRSV and E-SRST on the Same Site
Cisco UMG 8.5 supports enabling both SRSV and E-SRST provisioning on the same site in certain cases. In the supported model, CUCME-as-SRST is configured on the branch along with a SRSV-CUE device. A central call agent (CUCM) and voicemail system (CUC) is installed at the central site. These devices provide the primary telephony and voicemail services under normal conditions. A Cisco UMG at the central site monitors CUCM and CUC for changes/adds/deletes that must be pushed to the remote branch SRSV-CUE and CUCME-SRST sites.
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Figure 5 shows the deployment model for both SRSV and E-SRST that is supported in Cisco UMG 8.5.
Figure 5 E-SRST and SRSV Deployed on the Same Site
Voice Profile for Internet Mail (VPIM) Networking
Voice Profile for Internet Mail (VPIM) is supported in Cisco UMG 1.0 and later versions. The VPIM functionality requires the installation of VPIM licenses, with each license supporting up to 25 nodes per license. VPIM is typically not deployed with SRSV.
Cisco Unified Messaging Gateway (Cisco UMG) delivers the end-to-end message networking functionality required by larger distributed enterprises seamlessly migrating to Cisco's IP telephony solution. The majority of larger distributed enterprises consist of various legacy voice messaging products that do not support open standards. The Cisco UMG solution fulfills a gateway function for these networks, providing a method of intelligently routing messages, exchanging subscriber and directory information, and providing interoperability within a messaging network. It acts as a central hub for distributed messaging deployments using the following:
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Cisco UMG VPIM enables the messaging network to scale as required for the largest of implementations and simplifies configuration of all the endpoints. The number of Cisco Unity Express endpoints supported depends on the Cisco UMG module being used. For more information, see the Release Notes for Cisco Unified Messaging Gateway.
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VPIM Endpoint Management
Cisco Unified Messaging Gateway learns about endpoints either through autoregistration or if the endpoints are manually provisioned.
Autoregistration
Endpoints running Cisco Unity Express 3.1 and later support autoregistration with Cisco Unified Messaging Gateway. No other endpoint types support autoregistration.
The purpose of autoregistration between Cisco UMG and Cisco Unity Express is to facilitate scaling your messaging network while ensuring that messages can only be exchanged by trusted peers. Autoregistration is the means by which a messaging gateway can automatically "discover" legitimate endpoints. The messaging gateway authorizes such endpoints by validating shared secret information. Autoregistration also enables messaging gateways to learn about endpoint properties through directory exchange.
For a more detailed description of the autoregistration process, see the "Overview of the Autoregistration Process" section on page 67.
Manual Provisioning of Cisco Unity and Avaya Interchange Endpoints
The following types of endpoints cannot autoregister, and must be manually provisioned from Cisco UMG:
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Manually provisioning these endpoints serves the same purpose as the registration described previously, ensuring that information is only exchanged between trusted peers. Also, because these endpoint types do not support automatic directory exchange, you must configure the directory information for them on the messaging gateway that manages them.
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Directory Exchange Between Endpoints And Messaging Gateways
After endpoints are registered with or provisioned to a messaging gateway, this message gateway will propagate the endpoints' information to the rest of the network of Cisco UMGs.
Endpoints can:
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Remote Lookup Function
Subscribers can use the remote lookup function to search for a subscriber. The subscriber thus has the ability to:
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Managing a Network of Cisco UMG VPIM Nodes
Each messaging gateway is configured to recognize its peers. After endpoints are registered with or provisioned to a messaging gateway, this messaging gateway propagates the endpoints' information to the rest of the network of Cisco UMG nodes.
Cisco UMG VPIM uses the primary/secondary model to provide failover support. Each Cisco Unity Express endpoint identifies primary and secondary messaging gateway through its local configuration and autoregisters with both messaging gateways. For Cisco Unity, a DNS server is required for failover support, meaning that the messaging gateway domain name is mapped to two IP addresses on DNS: primary messaging gateway and secondary messaging gateway. Avaya Interchange does not support such failover provisions.
In the case of a firewall, a firewall pin hole must be opened to allow TCP connections between two different nodes (such as between an endpoint and Cisco UMG or between messaging gateways, and so on).
For more detailed information about deployment models for VPIM, see the Design Guide for Cisco Unified Messaging Gateway 1.0.
Administration Interfaces
Cisco UMG Release 8.5 utilizes both a command-line interface (CLI) and a graphical user interface (GUI).
Command-Line Interface
The CLI is a text-based interface accessed through a Telnet session to the router hosting the Cisco UMG. Those familiar with Cisco IOS command structure and routers will see similarities.
The Cisco UMG commands are structured much like the Cisco IOS CLI commands. However, the Cisco UMG CLI commands do not affect Cisco IOS configurations. After you log in to the Cisco UMG, the command environment is no longer the Cisco IOS environment.
See the "Entering and Exiting the Command Environment" section on page 15 for the instructions to enter the Cisco UMG CLI environment.
The CLI is accessible from a PC or server anywhere in the IP network.
The Cisco UMG features are configured as follows:
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CLI commands can also be used for routine monitoring and maintenance of the Cisco UMG system regardless of the feature licenses installed.
Graphical User Interface
Cisco UMG provides a GUI that is used to configure and operate the SRSV and E-SRST features. For information on using the GUI, see the online help in the application or the selected chapters later in this guide.
Some monitoring and maintenance functions may be available both using the CLI commands and through the GUI. Some basic maintenance functions in the GUI can also be used for VPIM networks.
For information on using the GUI to configure SRSV and/or E-SRST, and for routing maintenance operations, see Configuring Cisco Unified Messaging Gateway 8.5 Using the GUI: SRSV and E-SRST.
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You can also configure more sites for provisioning than you have purchased licenses for, but the provisioning process will only provision the number of sites purchased. For example, if you have purchased a license for 25 sites but configure the GUI to provision 50, the 25 sites with licenses will be provisioned, but you will receive an error message for the other 25 sites stating that no more licenses are available.
