Design Guide for Cisco Unity Release 5.x - Cisco Unity Failover and Standby Redundancy [Cisco Unity]

Table Of Contents

Cisco Unity Failover and Standby Redundancy

Comparison of Cisco Unity Failover and Standby Redundancy

Failover

Configuring Failover When Cisco Unity Servers Are Separated by a Firewall

Installing Exchange 2003 on the Cisco Unity Secondary Server in a Voice Messaging Configuration with Failover

Requirements for Spanning a Cisco Unity Failover Pair Across Redundant Data Centers

Standby Redundancy

Installing Exchange 2003 on the Cisco Unity Primary Server in a Standby Redundancy Configuration

Diagram of a Standby Redundancy Configuration

Cisco Unity Failover and Standby Redundancy

See the following sections:

•Comparison of Cisco Unity Failover and Standby Redundancy

•Failover

•Standby Redundancy

Comparison of Cisco Unity Failover and Standby Redundancy

Cisco Unity failover provides system-malfunction failover within a data center. Failover consists of two servers, a primary and a secondary. In general, the primary server is active and taking calls, while the secondary is inactive and not taking calls. Any changes to subscriber or configuration data on the primary server are automatically replicated to the secondary server. If the primary server stops functioning for some reason, the secondary server automatically becomes the active server and starts taking calls. The primary server temporarily becomes inactive.

Cisco Unity standby redundancy provides disaster-recovery failover across geographic locations. There are still two servers, a primary and a secondary, but they are installed in separate data centers, commonly in separate cities. If the data center in which the primary server is installed is affected by a natural disaster or other catastrophe, someone in (or with remote access to) the disaster-recovery facility manually activates the secondary server, and the secondary server begins taking calls.

For more information on how failover and standby redundancy work, see the "About Cisco Unity Failover" chapter in the applicable Failover Configuration and Administration Guide for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_feature_guides_list.html.

Failover

For a list of the requirements for a failover system, see the "Requirements for Cisco Unity Failover" section in the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html.

Configuring Failover When Cisco Unity Servers Are Separated by a Firewall

Revised May 6, 2008

When Exchange is the message store, you can separate Cisco Unity primary and secondary servers by a firewall. When IBM Lotus Domino is the message store, the primary and secondary servers cannot be separated by a firewall.

If the system includes a Cisco Unity voice recognition server, the primary and secondary Cisco Unity servers must be on the same side of the firewall as the Cisco Unity voice recognition server.

For additional requirements, see the "Failover Requirements for Separating Cisco Unity Servers by a Firewall" in the System Requirements for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html.

Installing Exchange 2003 on the Cisco Unity Secondary Server in a Voice Messaging Configuration with Failover

When Cisco Unity failover is installed in a Voice Messaging configuration, Exchange Server 2003 can be installed on the secondary server instead of on a separate, third server. Requirements for this configuration are listed in the "Requirements When the Message Store Is Installed on the Secondary Server" section of the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html.

Requirements for Spanning a Cisco Unity Failover Pair Across Redundant Data Centers

Revised May 6, 2008

Some customers maintain redundant data centers that are so well connected that they essentially form a single LAN. For these customers, failover may be a more suitable configuration than standby redundancy. For detailed requirements for this configuration, see the section "Failover Requirements for Separating Cisco Unity Servers by a WAN" in the System Requirements for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html.

Standby Redundancy

Note the following about a Cisco Unity system configured for standby redundancy:

•The standby redundancy configuration requires a minimum available bandwidth of 100 Mb/second between the data centers in which the Cisco Unity primary and secondary servers are installed. This is because of two bandwidth spikes, one caused by SQL Server, the other by Cisco Unity:

–Once daily (by default at 2:00 a.m.), SQL Server replicates data from the active server to the inactive server.

–Cisco Unity periodically replicates WAV files of voice names, greetings, call handlers, and interview handlers from the active server to the inactive server.

•If something happens to the data center in which the Cisco Unity server is installed, the customer must have:

–A way to reroute call traffic to the data center in which the secondary server is installed.

–Sufficient bandwidth for call traffic to the data center in which the secondary server is installed.

•Automatic failover must be disabled when Cisco Unity standby redundancy is configured. Therefore, if the primary server becomes unavailable, the customer must manually make the secondary server active before it begins taking calls.

For a list of the requirements for standby redundancy, see the "Requirements for Standby Redundancy" section in the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html.

Installing Exchange 2003 on the Cisco Unity Primary Server in a Standby Redundancy Configuration

When Cisco Unity is installed in a standby redundancy configuration, Exchange Server 2003 can be installed on the primary server instead of on a separate, third server. This reduces the number of servers required for a standby redundancy configuration, and also allows Cisco Unity and Exchange to be in the same data center except when the secondary server is active.

When the secondary Cisco Unity server is active, the primary server, on which Exchange is installed, is probably completely unavailable, which means that Exchange is also unavailable. The secondary Cisco Unity server answers calls, allows outside callers to look up subscriber extensions, and records voice messages. However, subscribers who check their voice messages hear the Unity Messaging Repository (UMR) conversation. This conversation explains that their Exchange server is not available, and lets them access voice messages that were sent after the primary Cisco Unity server became unavailable. Any voice messages sent after the primary became unavailable are stored in the UMR on the secondary Cisco Unity server. When the primary Cisco Unity server is active again and Exchange on the primary is available again, the voice messages stored in the UMR are routed to the subscriber mailboxes.

Caution If the message store is already installed on a separate platform, do not reconfigure the existing Cisco Unity system to move Exchange to the primary Cisco Unity server. Otherwise, the Cisco Unity standby redundancy system will not be supported. Only new installations of Cisco Unity with standby redundancy can be configured with Exchange on the primary server.

Note This configuration is not yet documented in System Requirements for Cisco Unity Release 5.0, in the Failover Configuration and Administration Guide for Cisco Unity Release 5.x, or in the Cisco Unity installation guide. When installing Cisco Unity in this configuration, use the Installation Guide for Cisco Unity Release 5.x in a Voice Messaging Configuration with Microsoft Exchange (With Failover Configured), but install Exchange on the primary server instead of on the secondary or on a separate server. You must install software on the primary server first because when you install Exchange administration software on the secondary server, the full version of Exchange must already be present in the environment.

•This configuration is supported only when Cisco Unity is installed in a Voice Messaging configuration.

•One Cisco Unity server is designated the primary server, and the other Cisco Unity server is designated the secondary (or standby) server.

•Both Cisco Unity servers must appear on the Cisco Unity Supported Platforms List at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_data_sheets_list.html and must belong to the same platform overlay.

•There must be a connection of 100 Mbps between the primary and secondary Cisco Unity servers.

•The network must meet the requirements listed in the "Network Requirements" section of System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/docs/voice_ip_comm/unity/5x/requirements/50cusysreq.html.

•If the Cisco Unity servers are being installed into an existing forest, both data centers must have one or more DC/GCs and one or more DNS servers.

If the Cisco Unity servers are being installed into a new forest, both must be DC/GCs in the same Active Directory domain.

•The names of both Cisco Unity servers must be 14 characters or shorter.

•Exchange Server 2003 administration must be installed on the secondary server.

•Both Cisco Unity servers must have the same enabled features and configurations.

•SQL Server 2000 Standard Edition must be installed on both Cisco Unity servers. (MSDE 2000 is not supported on either server with Cisco Unity standby redundancy.)

•The SQL Server 2000 services MSSQLSERVER and SQLSERVERAGENT on both Cisco Unity servers must be configured to log on as the same domain account, and the account must belong to the Local Administrators group on each server. SQLSERVERAGENT on the primary server must be able to log on to SQL Server on the secondary server by using Windows NT authentication.

•All software must be installed on the same drive and directories for both primary and secondary servers.

•The Cisco Unity servers must have Cisco Unity 5.0(1) ES1 installed.

Diagram of a Standby Redundancy Configuration

Figure 7-1 shows one possible configuration for a Cisco Unity standby redundancy system.

Figure 7-1 Cisco Unity Standby Redundancy Example Diagram

	Design Guide for Cisco Unity Release 5.x
	Cisco Unity Failover and Standby Redundancy
Design Guide for Cisco Unity Release 5.x Index Preface Design Guide Overview Cisco Unity Concepts Network Infrastructure Requirements Designing a Cisco Unity System with Exchange as the Message Store Designing a Cisco Unity System with Domino as the Message Store Integrating Cisco Unity with the Phone System Cisco Unity Failover and Standby Redundancy Voice-Recognition Access to Cisco Unity Migrating to Cisco Unity from Another Voice-Messaging System Design Differences Among Versions of Cisco Unity	Download this chapter Cisco Unity Failover and Standby Redundancy Download the complete book PDF Version of the Entire Guide (PDF - 2 MB) Table Of Contents Cisco Unity Failover and Standby Redundancy Comparison of Cisco Unity Failover and Standby Redundancy Failover Configuring Failover When Cisco Unity Servers Are Separated by a Firewall Installing Exchange 2003 on the Cisco Unity Secondary Server in a Voice Messaging Configuration with Failover Requirements for Spanning a Cisco Unity Failover Pair Across Redundant Data Centers Standby Redundancy Installing Exchange 2003 on the Cisco Unity Primary Server in a Standby Redundancy Configuration Diagram of a Standby Redundancy Configuration Cisco Unity Failover and Standby Redundancy See the following sections: •Comparison of Cisco Unity Failover and Standby Redundancy •Failover •Standby Redundancy Comparison of Cisco Unity Failover and Standby Redundancy Cisco Unity failover provides system-malfunction failover within a data center. Failover consists of two servers, a primary and a secondary. In general, the primary server is active and taking calls, while the secondary is inactive and not taking calls. Any changes to subscriber or configuration data on the primary server are automatically replicated to the secondary server. If the primary server stops functioning for some reason, the secondary server automatically becomes the active server and starts taking calls. The primary server temporarily becomes inactive. Cisco Unity standby redundancy provides disaster-recovery failover across geographic locations. There are still two servers, a primary and a secondary, but they are installed in separate data centers, commonly in separate cities. If the data center in which the primary server is installed is affected by a natural disaster or other catastrophe, someone in (or with remote access to) the disaster-recovery facility manually activates the secondary server, and the secondary server begins taking calls. For more information on how failover and standby redundancy work, see the "About Cisco Unity Failover" chapter in the applicable Failover Configuration and Administration Guide for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_feature_guides_list.html. Failover For a list of the requirements for a failover system, see the "Requirements for Cisco Unity Failover" section in the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html. Configuring Failover When Cisco Unity Servers Are Separated by a Firewall Revised May 6, 2008 When Exchange is the message store, you can separate Cisco Unity primary and secondary servers by a firewall. When IBM Lotus Domino is the message store, the primary and secondary servers cannot be separated by a firewall. If the system includes a Cisco Unity voice recognition server, the primary and secondary Cisco Unity servers must be on the same side of the firewall as the Cisco Unity voice recognition server. For additional requirements, see the "Failover Requirements for Separating Cisco Unity Servers by a Firewall" in the System Requirements for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html. Installing Exchange 2003 on the Cisco Unity Secondary Server in a Voice Messaging Configuration with Failover When Cisco Unity failover is installed in a Voice Messaging configuration, Exchange Server 2003 can be installed on the secondary server instead of on a separate, third server. Requirements for this configuration are listed in the "Requirements When the Message Store Is Installed on the Secondary Server" section of the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html. Requirements for Spanning a Cisco Unity Failover Pair Across Redundant Data Centers Revised May 6, 2008 Some customers maintain redundant data centers that are so well connected that they essentially form a single LAN. For these customers, failover may be a more suitable configuration than standby redundancy. For detailed requirements for this configuration, see the section "Failover Requirements for Separating Cisco Unity Servers by a WAN" in the System Requirements for Cisco Unity at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html. Standby Redundancy Note the following about a Cisco Unity system configured for standby redundancy: •The standby redundancy configuration requires a minimum available bandwidth of 100 Mb/second between the data centers in which the Cisco Unity primary and secondary servers are installed. This is because of two bandwidth spikes, one caused by SQL Server, the other by Cisco Unity: –Once daily (by default at 2:00 a.m.), SQL Server replicates data from the active server to the inactive server. –Cisco Unity periodically replicates WAV files of voice names, greetings, call handlers, and interview handlers from the active server to the inactive server. •If something happens to the data center in which the Cisco Unity server is installed, the customer must have: –A way to reroute call traffic to the data center in which the secondary server is installed. –Sufficient bandwidth for call traffic to the data center in which the secondary server is installed. •Automatic failover must be disabled when Cisco Unity standby redundancy is configured. Therefore, if the primary server becomes unavailable, the customer must manually make the secondary server active before it begins taking calls. For a list of the requirements for standby redundancy, see the "Requirements for Standby Redundancy" section in the System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/prod_installation_guides_list.html. Installing Exchange 2003 on the Cisco Unity Primary Server in a Standby Redundancy Configuration When Cisco Unity is installed in a standby redundancy configuration, Exchange Server 2003 can be installed on the primary server instead of on a separate, third server. This reduces the number of servers required for a standby redundancy configuration, and also allows Cisco Unity and Exchange to be in the same data center except when the secondary server is active. When the secondary Cisco Unity server is active, the primary server, on which Exchange is installed, is probably completely unavailable, which means that Exchange is also unavailable. The secondary Cisco Unity server answers calls, allows outside callers to look up subscriber extensions, and records voice messages. However, subscribers who check their voice messages hear the Unity Messaging Repository (UMR) conversation. This conversation explains that their Exchange server is not available, and lets them access voice messages that were sent after the primary Cisco Unity server became unavailable. Any voice messages sent after the primary became unavailable are stored in the UMR on the secondary Cisco Unity server. When the primary Cisco Unity server is active again and Exchange on the primary is available again, the voice messages stored in the UMR are routed to the subscriber mailboxes. Caution If the message store is already installed on a separate platform, do not reconfigure the existing Cisco Unity system to move Exchange to the primary Cisco Unity server. Otherwise, the Cisco Unity standby redundancy system will not be supported. Only new installations of Cisco Unity with standby redundancy can be configured with Exchange on the primary server. Note This configuration is not yet documented in System Requirements for Cisco Unity Release 5.0, in the Failover Configuration and Administration Guide for Cisco Unity Release 5.x, or in the Cisco Unity installation guide. When installing Cisco Unity in this configuration, use the Installation Guide for Cisco Unity Release 5.x in a Voice Messaging Configuration with Microsoft Exchange (With Failover Configured), but install Exchange on the primary server instead of on the secondary or on a separate server. You must install software on the primary server first because when you install Exchange administration software on the secondary server, the full version of Exchange must already be present in the environment. •This configuration is supported only when Cisco Unity is installed in a Voice Messaging configuration. •One Cisco Unity server is designated the primary server, and the other Cisco Unity server is designated the secondary (or standby) server. •Both Cisco Unity servers must appear on the Cisco Unity Supported Platforms List at http://www.cisco.com/en/US/products/sw/voicesw/ps2237/products_data_sheets_list.html and must belong to the same platform overlay. •There must be a connection of 100 Mbps between the primary and secondary Cisco Unity servers. •The network must meet the requirements listed in the "Network Requirements" section of System Requirements for Cisco Unity Release 5.0 at http://www.cisco.com/en/US/docs/voice_ip_comm/unity/5x/requirements/50cusysreq.html. •If the Cisco Unity servers are being installed into an existing forest, both data centers must have one or more DC/GCs and one or more DNS servers. If the Cisco Unity servers are being installed into a new forest, both must be DC/GCs in the same Active Directory domain. •The names of both Cisco Unity servers must be 14 characters or shorter. •Exchange Server 2003 administration must be installed on the secondary server. •Both Cisco Unity servers must have the same enabled features and configurations. •SQL Server 2000 Standard Edition must be installed on both Cisco Unity servers. (MSDE 2000 is not supported on either server with Cisco Unity standby redundancy.) •The SQL Server 2000 services MSSQLSERVER and SQLSERVERAGENT on both Cisco Unity servers must be configured to log on as the same domain account, and the account must belong to the Local Administrators group on each server. SQLSERVERAGENT on the primary server must be able to log on to SQL Server on the secondary server by using Windows NT authentication. •All software must be installed on the same drive and directories for both primary and secondary servers. •The Cisco Unity servers must have Cisco Unity 5.0(1) ES1 installed. Diagram of a Standby Redundancy Configuration Figure 7-1 shows one possible configuration for a Cisco Unity standby redundancy system. Figure 7-1 Cisco Unity Standby Redundancy Example Diagram
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