Table Of Contents
Comparison of Cisco SIP SRST 3.0 and Cisco Unified SIP SRST 4.0
Configuration and Upgrade Tasks
How to Upgrade from Cisco SIP SRST 3.0 to Cisco Unified SIP SRST 4.0
Enabling SIP-to-SIP Connection Capabilities
Getting Started
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Prior to version 4.0, the name of this product was Cisco SIP SRST.
This chapter describes the main tasks necessary for the following:
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Note that upgrades from Cisco SIP SRST 3.4 to Cisco Unified SIP SRST 4.0 are not impacted by the issues discussed in this chapter.
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Contents
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Comparison of Cisco SIP SRST 3.0 and Cisco Unified SIP SRST 4.0
Cisco SIP SRST 3.0, Cisco IOS Release 12.2(15)ZJ Through Cisco IOS Release 12.4
Cisco SIP SRST 3.0 was a predecessor to Cisco Unified SIP SRST 4.0. In Cisco SIP SRST 3.0, you could configure a Cisco IOS voice gateway to act as a SIP redirect server. The voice gateway would respond to the originator of a call with a SIP Redirect message, and the Redirect message allowed the SIP phone that originated the call to establish a call to its destination. In addition, several commands in voice register pool configuration mode were introduced that allowed registration permission control.
Cisco Unified SIP SRST V4.0, Cisco IOS Release 12.4(4)XC
With Cisco Unified SIP SRST 4.0, a SIP redirect server is not necessary. Instead, a back-to-back user agent (B2BUA) server routes the call as desired. A B2BUA is a separate call agent that has more features than a redirect server, which can accept and forward calls only. With a B2BUA you can also configure call blocking and call forwarding. In call forwarding, the B2BUA forwards calls on behalf of the phone, while maintaining a presence as call middleman in the call path.
Configuration and Upgrade Tasks
The table below lists the high-level steps you need to take to upgrade to Cisco Unified SIP SRST 4.0. It also lists the high-level steps you need to take in order to run Version 3.0 or Version 4.0.
If you are interested in Cisco SIP SRST 3.0 (using a redirect server), complete these procedures.
Cisco SIP SRST Version 3.0 provides a backup to an external SIP proxy server by providing basic registrar and redirect services. The following chapters provide full Version 3.0 information, including basic voice register pool configurations.
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If you are interested in Cisco Unified SIP SRST 4.0 (using a B2BUA) and have never used Cisco Unified SIP SRST in the past, complete these procedures.
VoIP-to-VoIP connections permit the termination and reorigination of transferred and forwarded calls over the VoIP network. The following task describes how to allow SIP connections:
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SIP registrar functionality in Cisco IOS software is a required part of Cisco Unified SIP SRST. A registrar accepts SIP Register requests and dynamically builds VoIP dial peers, allowing the Cisco IOS voice gateway software to route calls to SIP phones. The following task describes how to configure the SIP registrar:
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Configure a basic voice register pool:
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You are now ready to configure Version 4.0 features such as call blocking and call forwarding. The following chapter describes the call blocking and call forwarding configurations:
If you are currently running Version 3.0 and want to upgrade to Version 4.0, complete these procedures.
Since Version 4.0 uses a B2BUA and not a redirect server, call redirection must be disabled as described in the following task:
VoIP-to-VoIP connections permit the termination and reorigination of transferred and forwarded calls over the VoIP network. The following task describes how to allow SIP connections:
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You are now ready to configure Version 4.0 features such as call blocking and call forwarding. The following chapter describes the call blocking and call forwarding configurations:
How to Upgrade from Cisco SIP SRST 3.0 to Cisco Unified SIP SRST 4.0
This section contains the following procedures:
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Disabling Call Redirection
Because Version 4.0 uses a B2BUA and not a redirect server, call redirection must be disabled if it was previously enabled. Complete the following tasks as required, depending on whether call redirection was enabled globally or on a dial-peer basis.
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Disabling Call Redirection Globally
To disable global IP-to-IP call redirection for all VoIP dial peers, use voice service configuration mode.
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SUMMARY STEPS
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DETAILED STEPS
Disabling Call Redirection on a Specific VoIP Dial Peer
To disable IP-to-IP call redirection for a specific VoIP dial peer, disable it on the inbound dial peer where it was originally enabled.
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SUMMARY STEPS
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Enabling SIP-to-SIP Connection Capabilities
VoIP-to-VoIP connections permit the termination and reorigination of transferred and forwarded calls over the VoIP network. For Cisco Unified SIP SRST 4.0 we enable SIP-to-SIP connections for hairpin call routing. The B2BUA that routes the call uses the SIP-to-SIP connection. Because VoIP-to-VoIP connections are disabled on the router by default, they must be explicitly enabled to use call routing.
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What to Do Next
SIP registrar functionality in Cisco IOS software is a required part of Cisco Unified SIP SRST. By default, Cisco Unified SIP SRST is not enabled and cannot accept SIP register messages. To configure the SIP registrar to accept incoming SIP Register messages, see the "Configuring the SIP Registrar" chapter.
To configure a basic voice register pool, see "Configuring Backup Registrar Service to SIP Phones" section on page 26.
To configure call forwarding or call blocking, see the "Configuring Cisco Unified SIP SRST Features Using Back-to-Back User Agent Mode (for Version 3.4 and Version 4.0 Only)" chapter.
