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Cisco CallManager System Guide, Release 3.1(1)
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Index
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Preface
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Introduction
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Cisco IP Telephony Overview
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System Configuration Overview
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System-Level Configuration Settings
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Clustering
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Redundancy
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Call Admission Control
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Cisco TFTP
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Device Support
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Services
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Auto-Registration
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Partitions and Calling Search Spaces
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Understanding Route Plans
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Understanding the LDAP Directory
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Managing User Directory Information
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Media Resource Management
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Conference Bridges
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Transcoders
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Music On Hold
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Media Termination Points
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Catalyst DSP Resources for Transcoding and Conferencing
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SMDI Voice Mail Integration
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Cisco Unity Messaging Integration
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Cisco uOne Voice Messaging Integration
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Cisco DPA Integration
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Call Park
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Call Pickup and Group Call Pickup
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Cisco IP Phone Services
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Extension Mobility and Phone Login Features
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Understanding Cisco WebAttendant
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Custom Phone Rings
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Understanding Voice Gateways
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Cisco IP Phones
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Computer Telephony Integration
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Administrative Tools Overview
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Administrative Accounts and Passwords
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Feedback
Table Of Contents
Gateway Control Protocols and Trunk Interfaces
Cisco Catalyst 4000 and 6000 Voice Gateway Modules
Gateways, Dial Plans, and Route Groups
Gateway Configuration Checklist
Where to Find More Information
Understanding Voice Gateways
Cisco IP telephony gateways enable Cisco CallManager to communicate with non-IP telecommunications devices. Cisco CallManager supports several types of voice gateways.
This section covers the following topics:
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Gateway Control Protocols and Trunk Interfaces
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Gateway Control Protocols and Trunk Interfaces
This section describes the gateway control protocols and trunk interface protocols that are supported for configuring gateways in Cisco CallManager.
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Gateway Control Protocols
Gateway control protocols provide communication and control between Cisco CallManager and the voice gateway.
The amount and type of information you configure in Cisco CallManager Administration versus what is configured on the gateway varies, depending on whether gateway control protocol is MGCP, H.323, or Skinny:
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When MGCP is used, the Cisco CallManager controls routing and tones and provides supplementary services to the gateway. MGCP provides call preservation (calls are maintained during failover and failback), redundancy, dial plan simplification (no dial peer configuration is required on the gateway), hookflash transfer, and tone on hold. MGCP-controlled gateways do not require an MTP to enable supplementary services such as hold, transfer, call pickup, and call park.
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Compared to MGCP, H.323 requires more configuration on the gateway, because the gateway must maintain the dial plan and route patterns.
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Trunk Interfaces
Device protocols specify the time-division multiplexing (TDM) signaling interface between the voice gateway and the PSTN or external non-IP telephony devices. Supported TDM interfaces vary by gateway model. The following list gives available interfaces:
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Cisco CallManager assumes all loop start trunks lack positive disconnect supervision. We recommend that you configure trunks with positive disconnect supervision as ground start.
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Cisco Voice Gateways
Cisco CallManager supports several types of Cisco IP telephony gateways. These sections provide an overview of these supported gateways.
Standalone Voice Gateways
This section briefly describes the standalone, application-specific gateway models supported for use with Cisco CallManager.
Cisco Voice Gateway 200 Gateway
The Cisco IP Telephony VG200 provides a 10/100BaseT Ethernet port for connection to the data network. The following list gives available telephony connections:
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The MGCP VG200 integration with legacy voice-mail systems allows the Cisco CallManager to associate a port with a voice mailbox and connection.
Cisco Access Digital Trunk Gateways DT-24+/DT30+
The Cisco Access Digital Gateways DT-24+/DE-30+ provide the following features:
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Cisco Analog Access Station Gateways
Station gateways let you connect the Cisco CallManager to POTS analog telephones, interactive voice response (IVR) systems, fax machines, and voice-mail systems. Station gateways provide FXS ports. The AS-2, AS-4, and AS-8 models accommodate two, four, and eight Voice over IP (VoIP) gateway channels, respectively.
Cisco AS gateways communicate with Cisco CallManager using SGCP.
Cisco Access Analog Trunk Gateways
Analog trunk gateways let you connect the Cisco CallManager to standard PSTN central office (CO) or PBX trunks. Trunk gateways provide FXO ports. The AT-2, AT-4, and AT-8 models accommodate two, four, and eight VoIP gateway channels. The signaling type is loop start.
Cisco AT gateways communicate with Cisco CallManager using SGCP.
Cisco Catalyst 4000 and 6000 Voice Gateway Modules
Several available telephony modules for the Cisco Catalyst 4000 and 6000 family switches act as telephony gateways enabling you to implement IP telephony in your network using existing Cisco Catalyst 4000 or 6000 family devices.
You can install Catalyst 6000 voice gateway modules that are line cards in any Cisco Catalyst 6000 or 6500 series switch. You can install The Catalyst 4000 access gateway module in any Catalyst 4000 or 4500 series switch.
Cisco Catalyst 6000 8 Port Voice T1/E1 and Services Module
The Cisco Catalyst 6000 8 Port Voice T1/E1 and Services Modules provide the following features:
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Depending upon which port type is configured, the ports can serve as T1/E1 interfaces, or the ports will support transcoding or conferencing.
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Users have the flexibility to use each port for T1/E1 connections or as network resources for voice services.
Cisco Catalyst 4000 Access Gateway Module
The Cisco Catalyst 4000 Access Gateway Module provides the following telephony features:
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Cisco Catalyst 4224 Access Gateway Module
The Cisco Catalyst 4224 Access Gateway Module provides the following features:
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Cisco Catalyst 6000 24 Port FXS Analog Interface Module
The Cisco Catalyst 6000 24 Port FXS Analog Interface Module provides the following features:
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The Catalyst 6000 24 Port FXS Analog Interface Module provides 24 FXS ports for connecting to analog phones, conference room speaker phones, and fax machines. You can also connect to legacy voice-mail systems. Using SMDI, you can associate the ports with voice-mail extensions.
The FXS module provides legacy analog devices with connectivity into the IP network, enabling them to utilize the IP network infrastructure for toll-bypass applications and to communicate with devices such as IP phones and H.323 end stations. This module also supports fax relay, which enables compressed fax transmission over the IP WAN, preserving valuable WAN bandwidth for other data applications.
H.323 Gateways
H.323 devices comply with the H.323 communications standards and enable video conferencing over LANs and other packet-switched networks. You can add third-party H.323 devices or other Cisco devices that support H.323 (such as the Cisco 2600 series, 3600 series, or 5300 series gateways). You can also configure H.323 intercluster trunks to connect Cisco CallManagers in different clusters.
Cisco IOS H.323 Gateways
Cisco IOS H.323 gateways such as the Cisco 2600, 3600, 1750, 3810 V3, 7200 7500, AS5300, and VG200 provide full-featured routing capabilities as well as VoIP gateway functions. Refer to the documentation for each of these gateway types for information about support voice gateway features and configuration.
Intercluster Trunks
Use an intercluster trunk, an H.323 device, to connect two Cisco CallManagers in remote clusters. For information about configuring gatekeeper-controlled H.323 intercluster trunks for routing intercluster calls across a remote WAN link, refer to the Cisco IP Telephony Network Design Guide.
Voice Gateway Model Summary
Table 32-1 summarizes Cisco voice gateways supported by Cisco CallManager, with information about the gateway control protocols, trunk interfaces, and port types.
Gateways, Dial Plans, and Route Groups
Use dial plans to access or call out to the PSTN; route groups; and group specific gateways. Remote Cisco CallManagers across the IP WAN are configured as intercluster (H.323) gateways.
The different gateways used within the Cisco IP Telephony Solutions have dial plans configured in different places:
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The route group points to one or more gateways and can select the gateways for call routing based on preference. The route group can direct all calls to the primary device and then use the secondary devices when the primary is unavailable. This serves effectively as a trunk group. One or more route lists can point to the same route group. All devices in a given route group share the same characteristics such as path and digit manipulation. Route groups can perform digit manipulation that will override what was performed in the route pattern.
Configuration information associated with the gateway defines how the call is actually placed.
You can configure an H.323 gateway to be gatekeeper-controlled. This means that before a call is placed to an H.323 device it must successfully query the gatekeeper. Multiple clusters for inbound and outbound calls can share H.323 gateways, but MGCP and SGCP-based gateways are dedicated to a single Cisco CallManager cluster.
Gateway Failover and Failback
This section describes how Cisco voice gateways handle failover and failback.
MGCP Gateways
MGCP gateways receive a list of Cisco CallManagers according to the Cisco CallManager group, defined for the device pool assigned to the gateway. A Cisco CallManager group can contain one, two, or three Cisco CallManagers, listed in priority order, that the gateway uses there. If Cisco CallManager #1 goes down, then Cisco CallManager #2 is used. If #1 and #2 go down, then #3 is used.
Failback is the process of recovering a higher-priority Cisco CallManager when a gateway fails over to a secondary or tertiary Cisco CallManager. For Cisco MGCP gateways, higher priority Cisco CallManagers are periodically checked, statuses are taken and, when determined ready, marked as available again. The gateway then reverts to the highest available Cisco CallManager when all calls have gone idle, or within 24 hours, whichever occurs first. A failback may be forced by the administrator either by stopping the lower priority Cisco CallManager (calls are preserved), or by restarting the gateway (calls are terminated).
IOS H.323 Gateways
Using several enhancements to the dial-peer and voice class commands in Cisco IOS Release 12.1(2)T, Cisco IOS gateways can now support redundant Cisco CallManagers. A new command, h225 tcp timeout seconds, that has been added specifies the time it takes for the Cisco IOS gateway to establish an H.225 control connection for H.323 call setup. If the Cisco IOS gateway cannot establish an H.225 connection to the primary Cisco CallManager, it tries a second Cisco CallManager defined in another dial-peer statement. The Cisco IOS gateway shifts to the dial-peer statement with next highest preference setting.
The following example shows the configuration for H.323 gateway failover:
interface Loopback0ip address 1.1.1.1 255.255.255.0voip-gateway voip bind srcaddr 1.1.1.1dial-peer voice 101 voipdestination-pattern 1111session target ipv4:10.1.1.101preference 0voice class h323 1dial-peer voice 102 voipdestination-pattern 1111session target ipv4:10.1.1.102preference 1voice class h323 1voice class h323 1h225 timeout tcp establish 3
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voip-gateway voip bind srcaddrcommand for forcing H.323 always to use a specific source IP address in call setup. Without this command, the source address used in the setup might vary depending on protocol (RAS, H.225, H.245 or RTP).
SGCP Gateways
SGCP gateways are identical to MGCP gateways in terms of Cisco CallManager redundancy, failover and failback.
Gateway Configuration Checklist
Table 32-2 provides an overview of the steps required to configure gateways in Cisco CallManager, along with references to related procedures and topics.
Table 32-2 Gateway Configuration Checklist
Step 1
Install and configure the gateway or voice gateway module in the network.
Refer to the installation and configuration documentation for the model of gateway you are configuring.
Step 2
Gather the information you need to configure the gateway to operate with Cisco CallManager and to configure the trunk interface to the PSTN or external non-IP telephony device.
For Gateway Configuration Settings, refer to the Cisco CallManager Administration Guide.
For Port Configuration Settings, refer to the Cisco CallManager Administration Guide.
Step 3
On the gateway, perform any required configuration steps.
Refer to the voice feature software configuration documentation or Cisco IOS documentation for the model of gateway you are configuring.
Step 4
Add and configure the gateway in Cisco CallManager Administration.
For Adding Gateways to Cisco CallManager, refer to the Cisco CallManager Administration Guide.
Step 5
Add and configure ports on the gateway.
For Port Configuration Settings, refer to the Cisco CallManager Administration Guide.
Step 6
For FXS ports, add directory numbers, if appropriate.
For Adding a Directory Number and Directory Number Configuration Settings, refer to Cisco CallManager Administration Guide.
Step 7
Configure the dial plan for the gateway for routing calls out to the PSTN or other destinations.
This can include setting up a route group, route list, and route pattern for the Gateway in Cisco CallManager or, for some gateways, configuring the dial plan on the gateway itself.
For Dial Plan Architecture and Configuration, refer to the Cisco IP Telephony Network Design Guide.
See the "Dial Plan Architecture" section.
Step 8
Reset the gateway to apply the configuration settings.
For Resetting and Restarting Gateways, refer to the Cisco CallManager Administration Guide.
Tips
Where to Find More Information
Related Topics
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Additional Cisco Documentation
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http://www.cisco.com/univercd/cc/td/doc/product/voice/ip_tele/network/
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http://www.cisco.com/univercd/cc/td/doc/product/voice/c_access/vg_200/
