Cisco CP-7911G-CH1 System Administrator Manual

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Cisco Unified SCCP and SIP SRST  System Administrator Guide  (All Versions)

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April 23, 2012

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Text Part Number: OL-13143-04

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CONTENTS

Cisco Unified SCCP and SIP SRST Feature Overview 11

Contents 11

Cisco Unified SCCP SRST 11

Information About SCCP SRST 12 Prerequisites for Configuring Cisco Unified SCCP SRST 14 Restrictions for Configuring Cisco Unified SCCP SRST 17

Cisco Unified SIP SRST 19

Information About SIP SRST 19 Prerequisites for Configuring Cisco Unified SIP SRST 19 Restrictions for Configuring Cisco Unified SIP SRST 19

MGCP Gateways and SRST 23

Support for Cisco Unified IP Phones and Platforms 23

Finding Cisco IOS Software Releases That Support Cisco Unified SRST 23 Cisco Unified IP Phone Support 24 Platform and Memory Support 24 Cisco Unified Communications Manager Compatibility 24 Signal Support 25 Language Support 25 Switch Support 25

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Where to Go Next 25

Additional References 26

Related Documents 27 Standards 29 MIBs 29 RFCs 29 Technical Assistance 29

Obtaining Documentation, Obtaining Support, and Security Guidelines 29

Cisco Unified Survivable Remote Site Telephony Feature Roadmap 31

Contents 31

Documentation Organization 32

Feature Roadmap 33

Information About New Features in Cisco Unified SRST 38

New Features in Cisco Unified SRST Version 9.0 38

Cisco Unified SCCP and SIP SRST System Administrator Guide

Contents

New Features in Cisco Unified SRST Version 8.8 44 New Features in Cisco Unified SRST Version 8.0 45 New Features in Cisco Unified SRST Version 7.0/4.3 45 New Features in Cisco Unified SRST Version 4.2(1) 46 New Features in Cisco Unified SRST Version 4.1 46 New Features in Cisco Unified SRST Version 4.0 46 New Features in Cisco Unified SRST Version 3.4 48 New Features in Cisco SRST Version 3.3 48 New Features in Cisco SRST Version 3.2 49 New Features in Cisco SRST Version 3.1 52 New Features in Cisco SRST Version 3.0 53 New Features in Cisco SRST Version 2.1 57 New Features in Cisco SRST Version 2.02 59

Where to Go Next 61

Setting Up the Network 63

Contents 63

Information About Setting Up the Network 64

How to Set Up the Network 64

Enabling IP Routing 64 Enabling Cisco Unified SRST on an MGCP Gateway 64 Configuring DHCP for Cisco Unified SRST Phones 70 Specifying Keepalive Intervals 73

Where to Go Next 74

Cisco Unified SIP SRST 4.1 75

Contents 75

Prerequisites for Cisco Unified SIP SRST 4.1 75

Restrictions for Cisco Unified SIP SRST 4.1 76

Information About Cisco Unified SIP SRST 4.1 76

Out-of-Dialog REFER 76 Digit Collection on SIP Phones 77 Caller ID Display 78 Disabling SIP Supplementary Services for Call Forward and Call Transfer 78 Idle Prompt Status 78 Enhanced 911 Services 78

How to Configure Cisco Unified SIP SRST 4.1 Features 79

Enabling KPML for SIP Phones 79 Disabling SIP Supplementary Services for Call Forward and Call Transfer 81

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Configuring Idle Prompt Status for SIP Phones 82

Where to Go Next 83

Setting Up Cisco Unified IP Phones using SCCP 85

Contents 85

Information About Setting Up Cisco Unified IP Phones 85

How to Set Up Cisco Unified IP Phones 86

Configuring Cisco Unified SRST to Support Phone Functions 86 Configuring Cisco Unified 8941 and 8945 SCCP IP Phones 88 Verifying That Cisco Unified SRST Is Enabled 89 Configuring IP Phone Clock, Date, and Time Formats 90 Configuring IP Phone Language Display 92 Configuring Customized System Messages for Cisco Unified IP Phones 94 Configuring a Secondary Dial Tone 95 Configuring Dual-Line Phones 96 Configuring Eight Calls per Button (Octo-Line) 98 Configuring the Maximum Number of Calls 100 Troubleshooting 102

Contents

How to Set Up Cisco IP Communicator for Cisco Unified SRST 102

Verifying Cisco IP Communicator 103 Troubleshooting Cisco IP Communicator 103

Where to Go Next 103

Setting Up Cisco Unified IP Phones using SIP 105

Contents 105

Prerequisites for Configuring the SIP Registrar 105

Restrictions for Configuring the SIP Registrar 105

Information About Configuring the SIP Registrar 106

How to Configure the SIP Registrar 106

Configuring the SIP Registrar 106 Configuring Backup Registrar Service to SIP Phones 108 Configuring Backup Registrar Service to SIP Phones (Using Optional Commands) 112 Verifying SIP Registrar Configuration 115 Verifying Proxy Dial-Peer Configuration 117

Where to Go Next 120

Configuring Call Handling 123

Contents 123

Prerequisites for Configuring SIP SRST Features Using Back-to-Back User Agent Mode 123

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Contents

Restrictions for Configuring SIP SRST Features Using Back-to-Back User Agent Mode 124

Information About Configuring SCCP SRST Call Handling 124

H.323 VoIP Call Preservation Enhancements for WAN Link Failures 124 Toll Fraud Prevention 124

Information About Configuring SIP SRST Features Using Back-to-Back User Agent Mode 125

Cisco Unified SIP SRST and Cisco SIP Communications Manager Express Feature Crossover 125

How to Configure Cisco Unified SCCP SRST 127

Configuring Incoming Calls 127 Configuring Outgoing Calls 147

How to Configure Cisco Unified SIP SRST 164

Configuring SIP Phone Features 164 Configuring SIP-to-SIP Call Forwarding 166 Configuring Call Blocking Based on Time of Day, Day of Week, or Date 168 SIP Call Hold and Resume 172

How to Configure Optional Features 174

Enabling Three-Party G.711 Ad Hoc Conferencing 174 Defining XML API Schema 176

Where to Go Next 176

Configuring Secure SRST for SCCP and SIP 177

Contents 177

Prerequisites for Configuring Secure SRST 177

Restrictions for Configuring Secure SRST 178

Information About Configuring Secure SRST 179

Benefits of Secure SRST 179 Cisco IP Phones Clear-Text Fallback During Non-Secure SRST 179 Signaling Security on Unify SRST - TLS 180 Media Security on Unify SRST - SRTP 182 Establishment of Secure Cisco Unified SRST to the Cisco Unified IP Phone 182 Secure SRST Authentication and Encryption 184

How to Configure Secure Unified SRST 185

185

Preparing the Cisco Unified SRST Router for Secure Communication 186 Configuring Cisco Unified Communications Manager to the Secure Cisco Unified SRST Router 203 Enabling SRST Mode on the Secure Cisco Unified SRST Router 206 Configuring Secure SCCP SRST 207 Configuring Secure SIP Call Signaling and SRTP Media with Cisco SRST 221

Additional References 230

Related Documents 230

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Standards 231 MIBs 231 RFCs 231 Technical Assistance 231

Command Reference 232

Feature Information for Secure SCCP and SIP SRST 233

Where to Go Next 233

Integrating Voice Mail with Cisco Unified SRST 235

Contents 235

Information About Integrating Voice Mail with  Cisco Unified SCCP SRST 235

How to Integrate Voice Mail with Cisco Unified SCCP and SIP SRST 237

Configuring Direct Access to Voice Mail 237 Configuring Message Buttons 240 Redirecting to Cisco Unified Communications Manager Gateway 243 Configuring Call Forwarding to Voice Mail 243 Configuring Message Waiting Indication 247

Contents

Configuration Examples for SCCP SRST 249

Configuring Local Voice-Mail System (FXO and FXS): Example 249 Configuring Central Location Voice-Mail System (FXO and FXS): Example 250 Configuring Voice-Mail Access over FXO and FXS: Example 251 Configuring Voice-Mail Access over BRI and PRI: Example 251

How to Configure DTMF Relay for SIP Applications and Voice Mail 252

DTMF Relay Using SIP RFC 2833 252 DTMF Relay Using SIP Notify (Nonstandard) 254

Where to Go Next 256

Setting Video Parameters 257

Contents 257

Prerequisites for Setting Video Parameters 257

Restrictions for Setting Video Parameters 258

Information About Setting Video Parameters 258

Matching Endpoint Capabilities 259 Retrieving Video Codec Information 259 Call Fallback to Audio-Only 259 Call Setup for Video Endpoints 259 Flow of the RTP Video Stream 260

How to Set Video Parameters for Cisco Unified SRST 261

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Contents

Configuring Slow Connect Procedures 261 Verifying Cisco Unified SRST 262 Setting Video Parameters for Cisco Unified SRST 268

Troubleshooting Video for Cisco Unified SRST 270

Where to Go Next 270

Monitoring and Maintaining Cisco Unified SRST 271

Appendix A: Configuring Cisco Unified SIP SRST Features Using Redirect Mode 273

Contents 273

Prerequisites for Cisco Unified SIP SRST Features Using Redirect Mode 273

Restrictions for Cisco Unified SIP SRST Features Using Redirect Mode 273

Information About Cisco Unified SIP SRST Features Using Redirect Mode 274

How to Configure Cisco Unified SIP SRST Features Using Redirect Mode 274

Configuring Call Redirect Enhancements to Support Calls Between SIP IP Phones for Cisco Unified SIP SRST 274

Configuring Sending 300 Multiple Choice Support 277

Configuration Examples for Cisco Unified SIP SRST Features Using Redirect Mode 278

Cisco Unified SIP SRST: Example 279

Where to Go Next 280

Appendix B: Integrating Cisco Unified Communications Manager and Cisco Unified SRST to Use Cisco Unified SRST as a Multicast MOH Resource 281

Contents 281

Prerequisites for Using Cisco Unified SRST Gateways as a Multicast MOH Resource 282

Restrictions for Using Cisco Unified SRST Gateways as a Multicast MOH Resource 282

Information About Using Cisco Unified SRST Gateways as a Multicast MOH Resource 283

Cisco Unified SRST Gateways and Cisco Unified Communications Manager 283 Codecs, Port Numbers, and IP Addresses 284 Multicast MOH Transmission 286 MOH from a Live Feed 286 MOH from Flash Files 287

How to Use Cisco Unified SRST Gateways as a Multicast MOH Resource 288

Configuring Cisco Unified Communications Manager for Cisco Unified SRST Multicast MOH 288 Configuring Cisco Unified SRST for Multicast MOH from an Audio File 296 Configuring Cisco Unified SRST for MOH from a Live Feed 306

Configurations Examples for Cisco Unified SRST Gateways 311

MOH Routed to Two IP Addresses: Example 311 MOH Live Feed: Example 312

Cisco Unified SCCP and SIP SRST System Administrator Guide

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Feature Information for Cisco Unified SRST as a Multicast MOH Resource 312

Where to Go Next 313

Index

Contents

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Contents

Cisco Unified SCCP and SIP SRST System Administrator Guide

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Cisco Unified SCCP and SIP SRST Feature Overview

Revised: February 3, 2011

This chapter describes Cisco Unified Survivable Remote Site Telephony (Cisco Unified SRST) and what it does. It also includes information about support for Cisco Unified IP Phones and Platforms, specifications, features, prerequisites, restrictions and where to find additional reference documents.

For the most up-to-date information about Cisco Unified IP Phone support, the maximum number of Cisco Unified IP Phones, the maximum number of directory numbers (DNs) or virtual voice ports, and memory requirements for Cisco Unified SRST and Cisco Unified SIP SRST, see

Supported Firmware, Platforms, Memory, and Voice Products.

Cisco Unified SRST 4.0

Contents

• Cisco Unified SCCP SRST, page 11

• Cisco Unified SIP SRST, page 19

• MGCP Gateways and SRST, page 23

• Support for Cisco Unified IP Phones and Platforms, page 23

• Where to Go Next, page 25

• Additional References, page 26

• Obtaining Documentation, Obtaining Support, and Security Guidelines, page 29

Cisco Unified SCCP SRST

• Information About SCCP SRST, page 12

• Prerequisites for Configuring Cisco Unified SCCP SRST, page 14

• Restrictions for Configuring Cisco Unified SCCP SRST, page 17

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP SRST

Information About SCCP SRST

Cisco Unified SRST provides Cisco Unified CM with fallback support for Cisco Unified IP phones that are attached to a Cisco router on your local network. Cisco Unified SRST enables routers to provide call-handling support for Cisco Unified IP phones when they lose connection to remote primary, secondary, or tertiary Cisco Unified CM installations or when the WAN connection is down.

Cisco Unified CM supports Cisco Unified IP phones at remote sites attached to Cisco multiservice routers across the WAN. Prior to Cisco Unified SRST, when the WAN connection between a router and the Cisco Unified CM failed or when connectivity with Cisco Unified CM was lost for some reason, Cisco Unified IP phones on the network became unusable for the duration of the failure. Cisco Unified SRST overcomes this problem and ensures that the Cisco Unified IP phones offer continuous (although minimal) service by providing call-handling support for Cisco Unified IP phones directly from the Cisco Unified SRST router. The system automatically detects a failure and uses Simple Network Auto Provisioning (SNAP) technology to autoconfigure the branch office router to provide call processing for Cisco Unified IP phones that are registered with the router. When the WAN link or connection to the primary Cisco Unified CM is restored, call handling reverts back to the primary Cisco Unified CM.

When Cisco Unified IP phones lose contact with primary, secondary, and tertiary Cisco Unified CM, they must establish a connection to a local Cisco Unified SRST router to sustain the call-processing capability necessary to place and receive calls. The Cisco Unified IP phone retains the IP address of the local Cisco Unified SRST router as a default router in the Network Configuration area of the Settings menu. The Settings menu supports a maximum of five default router entries; however, Cisco Unified CM accommodates a maximum of three entries. When a secondary Cisco Unified CM is not available on the network, the local Cisco Unified SRST Router's IP address is retained as the standby connection for Cisco Unified CM during normal operation.

Cisco Unified SCCP and SIP SRST Feature Overview

Note Cisco Unified CM fallback mode telephone service is available only to those Cisco Unified IP

phones that are supported by a Cisco Unified SRST router. Other Cisco Unified IP phones on the network remain out of service until they re-establish a connection with their primary, secondary, or tertiary Cisco Unified CM.

Typically, it takes three times the keepalive period for a phone to discover that its connection to Cisco Unified CM has failed. The default keepalive period is 30 seconds. If the phone has an active standby connection established with a Cisco Unified SRST router, the fallback process takes 10 to 20 seconds after connection with Cisco Unified CM is lost. An active standby connection to a Cisco Unified SRST router exists only if the phone has the location of a single Cisco Unified CM in its Unified Communications Manager list. Otherwise, the phone activates a standby connection to its secondary Cisco Unified CM.

Note The time it takes for a Cisco Unified IP Phone to fallback to the SRST router can vary depending

on the phone type. Phones such as the Cisco 7902, Cisco 7905, and Cisco 7912 can take approximately 2.5 minutes to fallback to SRST mode.

If a Cisco Unified IP phone has multiple Cisco Unified CM in its Cisco Unified CM list, it progresses through its list of secondary and tertiary Cisco Unified CM before attempting to connect with its local Cisco Unified SRST router. Therefore, the time that passes before the Cisco Unified IP phone eventually establishes a connection with the Cisco Unified SRST router increases with each attempt to contact to a Cisco Unified CM. Assuming that each attempt to connect to a Cisco Unified CM takes about 1 minute, the Cisco Unified IP phone in question could remain offline for 3 minutes or more following a WAN link failure.

Cisco Unified SCCP and SIP SRST System Administrator Guide

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Cisco Unified SCCP and SIP SRST Feature Overview

Note During a WAN connection failure, when Cisco Unified SRST is enabled, Cisco Unified IP

phones display a message informing you that they are operating in Cisco Unified CM fallback mode. For example, the Cisco Unified IP Phone 7960G and Cisco Unified IP Phone 7940G display a "CM Fallback Service Operating" message, and the Cisco Unified IP Phone 7910 displays a "CM Fallback Service" message when operating in Cisco Unified CM fallback mode. When the Cisco Unified CM is restored, the message goes away and full Cisco Unified IP phone functionality is restored.

While in Cisco Unified CM fallback mode, Cisco Unified IP phones periodically attempt to re-establish a connection with Cisco Unified CM at the central office. Generally, the default time that Cisco Unified IP phones wait before attempting to re-establish a connection to a remote Cisco Unified CM is 120 seconds. The time can be changed in Cisco Unified CM; see the "Device Pool Configuration Settings" chapter in the appropriate Cisco Unified CM Administration Guide. A manual reboot can immediately reconnect Cisco Unified IP phones to Cisco Unified CM.

When a connection is re-established with Cisco Unified CM, Cisco Unified IP phones automatically cancel their registration with the Cisco Unified SRST Router. However, if a WAN link is unstable, Cisco Unified IP phones can bounce between Cisco Unified CM and Cisco Unified SRST. A Cisco Unified IP phone cannot re-establish a connection with the primary Cisco Unified CM at the central office if it is currently engaged in an active call.

Cisco Unified SCCP SRST



Cisco Unified SRST supports the following call combinations:

• SCCP phone to SCCP phone

• SCCP phone to PSTN/router voice-port

• SCCP phone to WAN VoIP using SIP or H.323

• SIP phone to SIP phone

• SIP phone to PSTN / router voice-port

• SIP phone to Skinny Client Control Protocol (SCCP) phone

• SIP phone to WAN VoIP using SIP

Figure 1 shows a branch office with several Cisco Unified IP phones connected to a Cisco Unified SRST

router. The router provides connections to both a WAN link and the PSTN. Typically, the Cisco

Unified IP phones connect to their primary Cisco Unified Communications Manager at the central office via the WAN link. When the WAN connection is down, the Cisco Cisco

Unified SRST router as a fallback for their primary Cisco Unified Communications Manager. The branch office Cisco

Unified IP phones are connected to the PSTN through the Cisco Unified SRST

Unified IP phones use the

router and are able to make and receive off-net calls.

     

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP SRST

IP IP IP

PSTN

network

WAN

disconnected

Central

Cisco Unified

Communications

Manager

Cisco Unified SRST

router

Fax

Telephone Telephone

Cisco IP phones

PCs

146613

Cisco Unified SCCP and SIP SRST Feature Overview

Figure 1 Branch Office Cisco Unifed IP Phones Connected to a Remote Central Cisco Unified

Communications Manage Operating in SRST Mode



On H.323 gateways for SCCP SRST, when the WAN link fails, active calls from Cisco Unified IP phones to the PSTN are not maintained by default. Call preservation may work with the no h225 timeout keepalive command.

Under default configuration, the H.323 gateway maintains a keepalive signal with Cisco Unified Communications

Manager and terminates H.323-to-PSTN calls if the keepalive signal fails, for example, if the WAN link fails. To disable this behavior and help preserve existing calls from local Cisco

Unified IP phones, you can use the no h225 timeout keepalive command. Disabling the keepalive mechanism only affects calls that will be torn down as a result of the loss of the H.225 keepalive signal. For information regarding disconnecting a call when an inactive condition is detected, see the

Inactive Call Detection document.

Prerequisites for Configuring Cisco Unified SCCP SRST

Before configuring Cisco Unified SRST, you must do the following:

• You have an account on Cisco.com to download software.

To obtain an account on Cisco.com, go to www.cisco.com and click Register at the top of the screen.

• You have purchased a Cisco Unified SRST license.

–

To purchase a license, go to http://www.cisco.com/cgi-bin/tablebuild.pl/ip-key.

–

To activate cme-srst feature license, see the Activating CME-SRST Feature License document.

Media

• Choose an appropriate Cisco Unified SRST version. Each SRST version supports a specific set of

IP phones, memory requirements, features, and DNs. See the

section on page 24 and the “Restrictions for Configuring Cisco Unified SCCP SRST” section on page 17.

Cisco Unified SCCP and SIP SRST System Administrator Guide

“Platform and Memory Support”

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Cisco Unified SCCP and SIP SRST Feature Overview

• Choose an appropriate phoneload. SRST only supports certain phoneloads that have been tested with

the various Cisco see the



Unified Communications Manager versions. For the most up-to-date phoneloads,

Cisco Unified SRST 4.3 Supported Firmware, Platforms, Memory, and Voice Products.

• If you have Cisco Unified Communications Manager already installed, verify that your version of 

Cisco Unified Communications Manager is compatible with your Cisco Unified SRST release. See the

“Cisco Unified Communications Manager Compatibility” section on page 24.

Installing Cisco Unified Communications Manager

When installing Cisco Unified Communications Manager, consider the following:

• See the installation instructions for your version in the Cisco Unified Communications Manager

Install and Upgrade Guides.

• Integrate Cisco Unified SRST with Cisco Unified Communications Manager. Integration is

performed from Cisco Unified Communications Manager. See the “Integrating Cisco Unified

SCCP SRST with Cisco Unified Communications Manager” section on page 16.

Cisco Unified SCCP SRST

Installing Cisco Unified SCCP SRST

Cisco Unified SRST versions have different installation instructions:

• Installing Cisco Unified SRST V3.0 and Later Versions, page 15

• Installing Cisco Unified SRST V2.0 and V2.1, page 15

• Installing Cisco Unified SRST V1.0, page 15

To update Cisco Unified SRST, follow the installation instructions described in this section.

Installing Cisco Unified SRST V3.0 and Later Versions

Install the Cisco IOS software release image containing the Cisco SRST or Cisco Unified SRST version that is compatible with your Cisco

Communications Manager Compatibility” section on page 24. Cisco IOS software can be downloaded

from the Cisco Software Center at http://www.cisco.com/public/sw-center/.

Cisco SRST and Cisco Unified SRST can be configured to support continuous multicast output of musicon-hold (MOH) from a flash MOH file in flash memory. For more information, see the

API Schema” section on page 176. If you plan to use MOH, go to the Technical Support Software

Download site at http://www.cisco.com/cgi-bin/tablebuild.pl/ip-iostsp and copy the music-on-hold.au file to the flash memory on your Cisco SRST or Cisco Unified SRST router.

Installing Cisco Unified SRST V2.0 and V2.1

Download and install Cisco SRST V2.0 or Cisco SRST V2.1 from the Cisco Software Center at

http://www.cisco.com/public/sw-center/.

Unified Communications Manager version. See the “Cisco Unified

“Defining XML

Installing Cisco Unified SRST V1.0

Cisco SRST V1.0 runs with Cisco Communications Manager V3.0.5 only. It is recommended that you upgrade to the latest Cisco

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Unified Communications Manager and Cisco Unified SRST versions.

Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP and SIP SRST Feature Overview

Cisco Unified SCCP SRST

Integrating Cisco Unified SCCP SRST with Cisco Unified Communications Manager

There are two procedures for integrating Cisco Unified SRST with Cisco Unified Communications Communications

If You Have Cisco Communications Manager V3.3 or Later Versions

If you have Cisco Communications Manager V3.3 or later versions, you must create an SRST reference and apply it to a device pool. An SRST reference is the IP address of the Cisco

Step 1 Create an SRST reference.

a. From any page in Cisco Unified Communications Manager, click System and SRST.

b. On the Find and List SRST References page, click Add a New SRST Reference.

c. On the SRST Reference Configuration page, enter a name in the SRST Reference Name field and

the IP address of the Cisco SRST router in the IP Address field.

d. Click Insert.

Manager. Procedure selection depends on the Cisco Unified Manager version that you have.

Unified SRST Router.

Step 2 Apply the SRST reference or the default gateway to one or more device pools.

a. From any page in Cisco Unified Communications Manager, click System and Device Pool.

b. On the Device Pool Configuration page, click on the required device pool icon.

c. On the Device Pool Configuration page, choose an SRST reference or “Use Default Gateway” from

the SRST Reference field’s menu.

If You Have Cisco Unified Communications Manager Version Prior to V3.3

If you have firmware versions that enable Cisco Unified SRST by default, no additional configuration is required on Cisco versions disable Cisco

Unified Communications Manager to support Cisco Unified SRST. If your firmware

Unified SRST by default, you must enable Cisco Unified SRST for each phone

configuration.

Step 1 Go to the Cisco Unified Communications Manager Phone Configuration page.

a. From any page in Cisco Unified Communications Manager, click Device and Phone.

b. In the Find and List Phones page, click Find.

c. After a list of phones appears, click on the required device name.

d. The Phone Configuration appears.

Step 2 In the Phone Configuration page, go to the Product Specific Configuration section at the end of the page,

choose Enabled from the Cisco

Step 3 Go to the Phone Configuration page for the next phone and choose Enabled from the Cisco Unified

Unified SRST field’s menu, and click Update.

SRST field’s menu by repeating Step 1 and Step 2.

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Cisco Unified SCCP and SIP SRST Feature Overview

Restrictions for Configuring Cisco Unified SCCP SRST

Table 1 provides a history of restrictions from Cisco SCCP SRST Version 1.0 to the present version of

Cisco Unified SCCP SRST.

Ta b l e 1 Restrictions from Cisco SCCP SRST from the Present Version to Version 1.0

Cisco Unified SCCP SRST

Cisco Unified SRST Version

Cisco IOS Release Restrictions

Ver si o n 4 . 1 12.4.(15)T • Enhanced 911 Services for Cisco Unified SRST does not interface with the Cisco

Emergency Responder.

• The information about the most recent phone that called 911 is not preserved after

a reboot of Cisco Unified SRST.

• Cisco Emergency Responder does not have access to any updates made to the

emergency call history table when remote IP phones are in Cisco Unified SRST fallback mode. Therefore, if the PSAP calls back after the Cisco Unified IP phones register back to Cisco Unified Communications Manager, Cisco Emergency Responder will not have any history of those calls. As a result, those calls will not get routed to the original 911 caller. Instead, the calls are routed to the default destination that is configured on Cisco Emergency Responder for the corresponding ELIN.

• For Cisco Unified Wireless IP Phone 7920 and 7921, a caller’s location can only be

determined by the static information configured by the system administrator. For more information, see the

Precautions for Mobile Phones in Configuring Enhanced

911 Services.

• The extension numbers of 911 callers can be translated to only two emergency

location identification numbers (ELINs) for each emergency response location (ERL).

• Using ELINs for multiple purposes can result in unexpected interactions with

existing Cisco Unified SRST features. These multiple uses of an ELIN can include configuring an ELIN for use as an actual phone number (ephone-dn, voice register dn, or FXS destination-pattern), a Call Pickup number, or an alias rerouting number. For more information, see the

Multiple Usages of an ELIN in Configuring

Enhanced 911 Services.

• There are a number of other ways that your configuration of Enhanced 911 Services

can interact with existing Cisco Unified SRST features and cause unexpected behavior. For a complete description of interactions between Enhanced 911 Services and existing Cisco Unified SRST features, see the

“Interactions with

Existing Cisco Unified SIP SRST Features” section on page 106.

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP and SIP SRST Feature Overview

Cisco Unified SCCP SRST

Table 1 Restrictions from Cisco SCCP SRST from the Present Version to Version 1.0(continued)

Cisco Unified SRST Version

Ver si o n 4 . 0

Ver si o n 3 . 4

Ver si o n 3 . 2

Ver si o n 3 . 1

Ver si o n 3 . 0

Ver si o n 2 . 1

Version 2.02

Version 2.01

Ver si o n 2 . 0

Cisco IOS Release Restrictions

12.4(4)XC

12.4(4)T

12.3(11)T

12.3(7)T

12.2(15)ZJ

12.3(4)T

• All of the restrictions in Cisco SRST Version 1.0.

• Caller-id display on supported Cisco Unified IP phones: SIP phones in fallback

mode displays the name and number of the caller. SCCP phones in fallback mode display only the caller-id number assigned to the line; the caller-ID name configuration for SCCP phones is not preserved during SRST fallback.

• Call transfer is supported only on the following:

–

VoIP H.323, VoFR, and VoATM between Cisco gateways running Cisco IOS Release 12.2(11)T and using the H.323 nonstandard information element

12.2(15)T

12.2(13)T

12.2(11)T

12.2(8)T1

12.2(8)T

12.2(2)XT

–

FXO and FXS loop-start (analog)

–

FXO and FXS ground-start (analog)

–

Ear and mouth (E&M) (analog) and DID (analog)

–

T1 channel-associated signaling (CAS) with FXO and FXS ground-start signaling

–

T1 CAS with E&M signaling

–

All PRI and BRI switch types

• The following Cisco Unified IP Phone function keys are dimmed because they are

not supported during SRST operation:

–

MeetMe

–

GPickUp (group pickup)

Ver si o n 1 . 0 12.2(2)XB

12.2(2)XG

12.1(5)YD

–

Park

–

Confrn (conference)

• Although the Cisco IAD2420 series integrated access devices (IADs) support the

Cisco Unified SRST feature, this feature is not recommended as a solution for enterprise branch offices.

• Does not support first generation Cisco Unified IP phones, such as Cisco IP Phone

30 VIP and Cisco IP Phone 12 SP+.

• Does not support other Cisco Unified Communications Manager applications or

services: Cisco IP SoftPhone, Cisco One: Voice and Unified Messaging Application, or Cisco IP Contact Center.

• Does not support Centralized Automatic Message Accounting (CAMA) trunks on

the Cisco 3660 routers.

Note If you are in one of the states in the United States of America where there is a

regulatory requirement for CAMA trunks to interface to 911 emergency services, and you would like to connect more than 48 Cisco Unified IP phones to the Cisco 3660 multiservice routers in your network, contact your local Cisco account team for help in understanding and meeting the CAMA regulatory requirements.

Cisco Unified SCCP and SIP SRST System Administrator Guide

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Cisco Unified SCCP and SIP SRST Feature Overview

Cisco Unified SIP SRST

• Information About SIP SRST, page 19

• Prerequisites for Configuring Cisco Unified SIP SRST, page 19

• Restrictions for Configuring Cisco Unified SIP SRST, page 19

Information About SIP SRST

This guide describes Cisco Unified SRST functionality for SIP networks. Cisco Unified SIP SRST provides backup to an external SIP proxy server by providing basic registrar and redirect server or back-to-back user agent (B2BUA) services. These services are used by a SIP IP phone in the event of a WAN connection outage when the SIP phone is unable to communicate with its primary SIP proxy.

Cisco Unified SIP SRST can support SIP phones with standard RFC 3261 feature support locally and across SIP WAN networks. With Cisco Unified SIP SRST, SIP phones can place calls across SIP networks in the same way as SCCP phones.

Cisco Unified SIP SRST supports the following call combinations:

• SIP phone to SIP phone

Cisco Unified SIP SRST

• SIP phone to PSTN / router voice-port

• SIP phone to Skinny Client Control Protocol (SCCP) phone

• SIP phone to WAN VoIP using SIP

SIP proxy, registrar, and B2BUA servers are key components of a SIP VoIP network. These servers are usually located in the core of a VoIP network. If SIP phones located at remote sites at the edge of the VoIP network lose connectivity to the network core (because of a WAN outage), they may be unable to make or receive calls. Cisco Unified SIP SRST functionality on a SIP PSTN gateway provides service reliability for SIP-based IP phones in the event of a WAN outage. Cisco Unified SIP SRST enables the SIP IP phones to continue to make and receive calls to and from the PSTN and also to make and receive calls to and from other SIP IP phones.

To see a branch office Cisco Unifed IP Phones connected to a remote central Cisco Unified CM Operating in SRST mode, see

Figure 1.

Prerequisites for Configuring Cisco Unified SIP SRST

Before configuring Cisco Unified SIP SRST, you must do the following:

• An SRST feature license is required to enable the Cisco Unified SIP SRST feature. Contact your

account representative if you have further questions.

Restrictions for Configuring Cisco Unified SIP SRST

Table 2 provides a history of restrictions from Cisco SIP SRST Version 3.0 to the present version of

Cisco Unified SIP SRST.

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP and SIP SRST Feature Overview

Cisco Unified SIP SRST

Ta b l e 2 Restrictions from Cisco SIP SRST from the Present Version to Version 3.0

Cisco Unified SRST Version

Cisco IOS Release Restrictions

Ver si o n 8 . 0 15.1(1)T • SIP phones may be configured on the Cisco Unified CM with an Authenticated

device security mode. The Cisco Unified CM ensures integrity and authentication for the phone using a TLS connection with NULL-SHA cipher for signaling. If such an Authenticated SIP phone fails over to the Cisco Unified SRST device, and if the Cisco Unified CM and SRST device are configured to support secure SIP SRST, it will register using TCP instead of TLS/TCP, thus disabling the Authenticated mode until the phone fails back to the Cisco Unified CM.

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Cisco Unified SCCP and SIP SRST Feature Overview

Table 2 Restrictions from Cisco SIP SRST from the Present Version to Version 3.0(continued)

Cisco Unified SIP SRST

Cisco Unified SRST Version

Cisco IOS Release Restrictions

Ver si o n 4 . 1 12.4.(15)T • Cisco Unified SRST does not support BLF speed-dial notification, call forward all

synchronization, dial plans, directory services, or music-on-hold (MOH).

• Prior to SIP phone load 8.0, SIP phones maintained dual registration with both

Cisco

Unified Communications Manager and Cisco Unified SRST simultaneously. In SIP phone load 8.0 and later versions, SIP phones use keepalive to maintain a connection with Cisco Cisco

Unified Communications Manager. Every two minutes, a SIP phone sends a keepalive message to Cisco

Unified SRST during active registration with

Unified SRST. Cisco Unified SRST responds to this keepalive with a 404 message. This process repeats until fallback to Cisco

Unified SRST occurs. After fallback, SIP phones send a keepalive message every two minutes to Cisco are registered with Cisco

Unified Communications Manager while the phones

Unified SRST. Cisco Unified SRST continues to support

dual registration for SIP phone loads older than 8.0.

• Enhanced 911 Services for Cisco Unified SRST does not interface with the

Cisco

Emergency Responder.

• The information about the most recent phone that called 911 is not preserved after

a reboot of Cisco

• Cisco Emergency Responder does not have access to any updates made to the

emergency call history table when remote IP Phones are in Cisco

Unified SRST.

Unified SRST fallback mode. Therefore, if the PSAP calls back after the Cisco Unified IP Phones register back to Cisco Cisco

Emergency Responder will not have any history of those calls. As a result,

Unified Communications Manager,

those calls will not get routed to the original 911 caller. Instead, the calls are routed to the default destination that is configured on Cisco

Emergency Responder for the

corresponding ELIN.

• For Cisco Unified Wireless 7920 and 7921 IP Phones, a caller’s location can only

be determined by the static information configured by the system administrator. For more information, see

Precautions for Mobile Phones in Configuring Enhanced

911 Services.

• The extension numbers of 911 callers can be translated to only two emergency

• Using ELINs for multiple purposes can result in unexpected interactions with

• There are a number of other ways that your configuration of Enhanced 911 Services

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location identification numbers (ELINs) for each emergency response location (ERL).

existing Cisco

Unified SRST features. These multiple uses of an ELIN can include configuring an ELIN for use as an actual phone number (ephone-dn, voice register dn, or FXS destination-pattern), a Call Pickup number, or an alias rerouting number. For more information, see

Multiple Usages of an ELIN in Configuring

Enhanced 911 Services.

can interact with existing Cisco Unified SRST features and cause unexpected behavior. For a complete description of interactions between Enhanced 911 Services

and existing Cisco Unified SRST features, see the “Interactions with

Existing Cisco Unified SIP SRST Features” section on page 106.

Cisco Unified SCCP and SIP SRST System Administrator Guide

Cisco Unified SCCP and SIP SRST Feature Overview

Cisco Unified SIP SRST

Table 2 Restrictions from Cisco SIP SRST from the Present Version to Version 3.0(continued)

Cisco Unified SRST Version

Ver si o n 4 . 0

Ver si o n 3 . 4

Ver si o n 3 . 2

Ver si o n 3 . 1

Ver si o n 3 . 0

Cisco IOS Release Restrictions

12.4(4)XC

12.4(4)T

12.3(11)T

12.3(7)T

12.2(15)ZJ

12.3(4)T

Not Supported

• MOH is not supported for a call hold invoked from a SIP phone. A caller hears only

silence when placed on hold by a SIP phone.

• As of Cisco IOS Release 12.4(4)T, bridged call appearance, find-me, incoming call

screening, paging, SIP presence, call park, call pickup, and SIP location are not supported.

• SIP-NAT is not supported.

• Cisco Unity Express is not supported.

• Transcoding is not supported.

Phone Features

• For call waiting to work on the Cisco ATA and Cisco IP Phone 7912 and Cisco

Unified IP Phone 7905G with a 1.0(2) build, the incoming call leg should be configured with the G.711 codec.

Note Cisco Unified IP Phone 7905G, Cisco Unified IP Phone 7912G, and Cisco

Analog Telephone Adaptor (ATA) 186 are not capable of dual registration; thus they are not supported and have limited functionality with Cisco Unified SIP SRST.

General

• Call detail records (CDRs) are only supported by standard IOS RADIUS support;

CDRs are not supported otherwise.

• All calls must use the same codec, either G.729r8 or G.711.

• Calls that have been transferred cannot be transferred a second time.

• URL dialing is not supported. Only number dialing is supported.

• The SIP registrar functionality provided by Cisco Unified SIP SRST provides no

security or authentication services.

• SIP IP phones that do not support dual concurrent registration with both their

primary and their backup SIP proxy or registrar may be unable to receive incoming calls from the Cisco Unified SIP SRST gateway during a WAN outage. These phones may take a significant amount of time to discover that their primary SIP proxy or registrar is unreachable before they initiate a fallback registration to their backup proxy or registrar (the SIP SRST gateway).

• SIP-phone-to-SIP-trunk support requires Refer and 302/300 Redirection to be

supported by the SIP trunk (Version 3.0).

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Cisco Unified SCCP and SIP SRST Feature Overview

MGCP Gateways and SRST

MGCP fallback is a different feature than SRST and, when configured as an individual feature, can be used by a PSTN gateway. To use SRST as your fallback mode on an MGCP gateway, SRST and MGCP fallback must both be configured on the same gateway. MGCP and SRST have had the capability to be configured on the same gateway since Cisco IOS Release 12.2(11)T.

To make outbound calls while in SRST mode on your MGCP gateway, two fallback commands must be configured on the MGCP gateway. These two commands allow SRST to assume control over the voice port and over call processing on the MGCP gateway. With Cisco IOS earlier than 12.3(14)T, the two commands are the ccm-manager fallback-mgcp and call application alternate commands. With Cisco

IOS releases after 12.3(14)T, the ccm-manager fallback-mgcp and service commands must be configured. A complete configuration for these commands is shown in the section the

Unified SRST on an MGCP Gateway” section on page 64.

Note The commands listed above are ineffective unless both commands are configured. For instance, your

configuration will not work if you only configure the ccm-manager fallback-mgcp command.

For more information on the fallback methods for MGCP gateways, see the Configuring MGCP Gateway

Support for Cisco Unified Communications Manager document or the MGCP Gateway Fallback Transition to Default H.323 Session Application document.

MGCP Gateways and SRST

“Enabling Cisco

Support for Cisco Unified IP Phones and Platforms

The following sections provide information about Cisco Feature Navigator and the histories of Cisco Unified IP Phone, platform, and Cisco Unified CM support from Cisco SRST Version 1.0 to the present version of Cisco Unified SRST.

• Finding Cisco IOS Software Releases That Support Cisco Unified SRST, page 23

• Cisco Unified IP Phone Support, page 24

• Platform and Memory Support, page 24

• Cisco Unified Communications Manager Compatibility, page 24

• Signal Support, page 25

• Language Support, page 25

• Switch Support, page 25

Finding Cisco IOS Software Releases That Support Cisco Unified SRST

Note With Cisco IOS Release 12.4(15)T, the number of SIP phones supported on each platform is now

equivalent to the number of SCCP phones supported. For example, 3845 now supports 720 phones regardless of whether these are SIP or SCCP.

To access Cisco Feature Navigator, go to http://www.cisco.com/go/cfn. An account on Cisco.com is not required.

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Support for Cisco Unified IP Phones and Platforms

See Cisco Unified CME and Cisco IOS Software Version Compatibility Matrix for related compatibility information.

Cisco Unified IP Phone Support

For the most up-to-date information about Cisco Unified IP Phone support, see Compatibility

Information.

For ATAs that are registered to a Cisco Unified SRST system to participate in FAX calls, they must have their ConnectMode parameter set to use the "standard payload type 0/8" as the RTP payload type in FAX passthrough mode. For ATAs used with Cisco Unified SRST 4.0 and higher versions, this is done by setting bit 2 of the ConnectMode parameter to 1 on the ATA. For more information, see the

and Defaults chapter in Cisco ATA 186 and Cisco ATA 188 Analog Telephone Adaptor Administrator's Guide for SCCP.

During Cisco Unified CM fallback, Cisco Unified SRST considers the Cisco VG248 to be a group of Cisco Unified IP phones. Cisco Unified SRST counts each of the 48 ports on the Cisco VG248 as a separate Cisco Unified IP phone. Support for Cisco VG248 Version 1.2(1) and higher versions is available as of Cisco SRST Version 2.1. For more information, see

Data Sheet and Cisco VG248 Analog Phone Gateway Version 1.2(1) Release Notes.

Cisco Unified SCCP and SIP SRST Feature Overview

Parameters

Cisco VG248 Analog Phone Gateway

Platform and Memory Support

For the most up-to-date information about Platform and Memory Support, see Compatibility

Information.

Determining Platform Support Through Cisco Feature Navigator

Cisco IOS software is packaged in feature sets that are supported on specific platforms. To get updated information regarding platform support for this feature, access Navigator dynamically updates the list of supported platforms as new platform support is added for the feature.

Availability of Cisco IOS Software Images

Platform support for particular Cisco IOS software releases is dependent on the availability of the software images for those platforms. Software images for some platforms may be deferred, delayed, or changed without prior notice. For updated information about platform support and availability of software images for each Cisco Cisco

Feature Navigator.

For the most up-to-date information about Cisco IOS software images, see Compatibility Information .

IOS software release, see the online release notes or, if supported,

Cisco Unified Communications Manager Compatibility

Cisco Feature Navigator. Cisco Feature

See Cisco Unified Communications Manager Compatibility Matrix.

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Cisco Unified SCCP and SIP SRST Feature Overview

Signal Support

Cisco Unified SRST supports FXS, FXO, T1, E1, and E1 R2 signals.

Language Support

See Cisco Unified Communications Manager Express Cisco Unified CME Localization Matrix.

Switch Support

Cisco SRST 3.2 and later versions support all PRI and BRI switches including the following:

• basic-1tr6

• basic-5ess

• basic-dms100

• basic-net3

• basic-ni

• basic-ntt NTT switch type for Japan

Where to Go Next

• basic-ts013

• primary-4ess Lucent 4ESS switch type for the United States

• primary-5ess Lucent 5ESS switch type for the United States

• primary-dms100 Northern Telecom DMS-100 switch type for the United States

• primary-net5 NET5 switch type for the United Kingdom, Europe, Asia, and Australia

• primary-ni National ISDN switch type for the United States

• primary-ntt NTT switch type for Japan

• primary-qsig QSIG switch type

• primary-ts014 TS014 switch type for Australia (obsolete)

Where to Go Next

The next chapters of this book describe how to configure Cisco Unified SIP SRST. As shown in Tabl e 3, each chapter takes you through tasks in the order in which they need to be performed. The first task for configuring Cisco Unified SRST is to ensure that the basic software and hardware in your system are configured correctly for Cisco Unified SRST.

Ta b l e 3 Cisco Unified SRST Configuration Sequence

Task Where Task Is Described

1. Setting up a Cisco Unified SRST system

to communicate with your network

2. Configuring Version 4.1 features Cisco Unified SIP SRST 4.1, page 75

3. Setting up the basic Cisco Unified SRST

phone configuration using SCCP

Setting Up the Network, page 63

Setting Up Cisco Unified IP Phones using SCCP, page 85

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Cisco Unified SCCP and SIP SRST System Administrator Guide

Additional References

Table 3 Cisco Unified SRST Configuration Sequence(continued)

Task Where Task Is Described

4. Providing a backup to an external SIP

proxy server by supplying basic registrar services

5. Configuring incoming and outgoing calls Configuring Call Handling, page 123

6. Configuring optional security for SRST Configuring Secure SRST for SCCP and SIP, page 177

7. Setting up voice mail Integrating Voice Mail with Cisco Unified SRST,

8. Setting up video parameters Setting Video Parameters, page 257

9. Monitoring and maintaining Cisco

Unified Survivable Remote Site

Telephony (SRST)

Additional References

Cisco Unified SCCP and SIP SRST Feature Overview

Setting Up Cisco Unified IP Phones using SIP, page 105

page 235

Monitoring and Maintaining Cisco Unified SRST, page 271

The following sections provide additional references related to Cisco Unified SIP SRST:

• Related Documents, page 27

• Standards, page 29

• MIBs, page 29

• RFCs, page 29

• Technical Assistance, page 29

Cisco Unified SCCP and SIP SRST System Administrator Guide

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Cisco Unified SCCP and SIP SRST Feature Overview

Cisco CP-7911G-CH1 System Administrator Manual

Specifications and Main Features

Frequently Asked Questions

User Manual