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Cisco Unified Communications Manager (CallManager)

IPv6 Deployment in Unified Communications Networks with Cisco Unified Communications Manager 8.0(x)

Document ID: 112997

Updated: May 18, 2011

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Introduction

Internet Protocol version 6 (IPv6), which is the latest version of the Internet Protocol (IP) that uses packets to exchange data, voice, and video traffic over digital networks, increases the number of network address bits from 32 bits in IPv4 to 128 bits. IPv6 support in the Cisco Unified Communications Manager network allows the network to behave transparently in a dual-stack environment and provides additional IP address space and autoconfiguration capabilities to devices that are connected to the network.

Cisco recommends that you deploy IPv6 in a dual-stack Cisco Unified Communications Manager (Unified CM) cluster with approved dual-stack devices (phones, gateways, and so forth). This approach is recommended to avoid IPv6-only deployments, which are not currently supported in production environments. Single-site call processing deployments, multiple-site distributed call processing deployments, and multiple-site deployments with centralized call processing are supported.

This document provides design considerations and configuration guidelines for deploying IPv6 in a Cisco Unified Communications System.

Prerequisites

Requirements

The following IPv6 system requirements exist for Cisco Unified Communications Manager:

  • Cisco Unified Communications Manager 7.1 or later on each server in the cluster

  • These Cisco Unified IP Phones that are running SCCP support IPv6: 7906G, 7911G, 7931G, 7942G, 7945G, 7962G, 7965G, and the 7975G.

  • DHCPv6 server that can issue IPv6 addresses and DNS server that can resolve host names to IPv6 addresses. Consider using Cisco Network Registrar (CNR) 6.2.

    Note: If you want to do so, you can configure a Cisco IOS® router or switch as a DHCPv6 server; for example, you can configure a Cisco Catalyst 3560 Series Switch or a Cisco Catalyst 3750 Series Switch that runs 12.2(46)SE (or later) as a DHCPv6 server. Before you configure this router/switch, verify that your router/switch supports the Cisco vendor-specific DHCPv6 information options that are required for IPv6 and DHCPv6 support.

  • Cisco IOS release that is compatible with Cisco Unified Communications Manager 8.0(x), and that is installed and configured on the gateways and the Cisco IOS MTP for IPv6. For more information, refer to Cisco Feature Navigator.

Components Used

The information in this document is based on Cisco Unified Communications Manager 8.0(x).

The information in this document was created from the devices in a specific lab environment. All of the devices used in this document started with a cleared (default) configuration. If your network is live, make sure that you understand the potential impact of any command.

Conventions

Refer to the Cisco Technical Tips Conventions for more information on document conventions.

Introducing IPv6 for Cisco Unified Communications Manager

Task

IPv6 impacts the Cisco CallManager, CTIManager, and Certificate Authority Proxy Function services in Cisco Unified Serviceability. Depending on the configuration tasks that you perform in Cisco Unified Communications Manager Administration, you might need to restart these services after you configure IPv6.

This section contains information on these topics:

  • CTI Applications

  • Cisco Unified Communications Manager

  • Cisco Unified IP Phones

  • DHCPv6

  • DNS

  • Gateways

  • Media Termination Points

  • SIP Trunks

  • TFTP Server

CTI Applications

CTI applications connect to the CTI Manager by using either an IPv4 or an IPv6 address. If you set the Enable IPv6 enterprise parameter to True in Cisco Unified Communications Manager Administration, the CTI Manager can support CTI connections from applications that use IPv6 addresses.

Cisco Unified Communications Manager

This section describes how Cisco Unified Communications Manager supports devices that use IPv4, IPv6, or IPv4 and IPv6. In addition, this section describes how Cisco Unified Communications Manager runs in dual-stack mode, how Cisco Unified Communications Manager can process calls for IPv4 and IPv6 devices, and how Cisco Unified Communications Manager can reserve and allocate bandwidth for IPv4 and IPv6 calls.

See the following sections:

  • Cisco Unified Communications Manager Server: For Cisco Unified Communications Manager to support devices that use IPv6, including dual-stack devices, which can provide both IPv4 and IPv6 addresses, you must configure Cisco Unified Communications Manager, so it runs in dual-stack mode; that is, you must ensure that the Cisco Unified Communications Manager server has both an IPv4 address and an IPv6 address that is configured for it, so it can interact and support devices that use IPv4 only, IPv6 only, or both IPv4 and IPv6.

    1. Enable IPv6 by using the set network ipv6 service enable command.

    2. Set a static IPv6 address for your server by using the set network ipv6 static_address <addr> <mask> command. The DHCPv6 client is also supported, but using it is not recommended.

    3. In order to view the platform's IPv6 address settings, use the show network ipv6 settings command. This is an example output from this command:

      IPv6 : enabled
      DHCPv6 : disabled
      IPv6 addresses:
      Address:2001:db8:c18:1:21c:c4ff:feef:ca0 Mask:64
      Scope:Global Duplicate:no
      Address:fe80::21c:c4ff:feef:ca0 Mask:64
      Scope:Link
    4. For Cisco Unified Communications Manager, set the Enable IPv6 enterprise parameter to True, which ensures that Cisco Unified Communications Manager runs in dual-stack mode. select Enterprise Parameters > IPv6 Configuration Modes to configure the following cluster-wide IPv6 settings for each Unified CM server.

      cucmipv6-01.gif

    5. In Cisco Unified Communications Operating System, select Settings > IP > Ethernet IPv6. The Ethernet IPv6 Configuration window displays.

      cucmipv6-02.gif

    6. Check the Update with Reboot check box. For the IPv6 settings in this window to take effect, you must reboot the server. Click Save. The server reboots immediately after you click Save.

    7. After you have configured the server platform IPv6 address, define the IPv6 address for each Unified CM server by using Cisco Unified CM Administration. Select System > Server, and enter the IPv6 address in the IPv6 Name field. The IPv6 address in this field enables Skinny Client Control Protocol (SCCP) phones to retrieve the IPv6 address of this Unified CM from the configuration file downloaded from the TFTP server.

      cucmipv6-03.gif

  • Call Processing: By running in dual-stack mode, Cisco Unified Communications Manager can set up calls under these circumstances:

    • When all devices support IPv4 only.

    • When all devices support IPv6 only.

    • When all devices run in dual-stack mode, in which case, Cisco Unified Communications Manager uses the configuration for the IP Addressing Mode Preference for Signaling setting for signaling events and the IP Addressing Mode Preference for Media enterprise parameter for media events.

    • When one device supports IPv4 and another device supports IPv6, in which case, Cisco Unified Communications Manager attempts to insert an MTP into the call that can translate IPv4 to IPv6.

  • Call Admission Control (CAC): While using IPv6 requires 20 more bytes of data in its header than IPv4, an IPv6 call requires more bandwidth than a similar IPv4 call that uses the same codec/media payload type. For example, a G.711 call that uses IPv4 uses 80 kb/s of bandwidth. Whereas, a G.711 call that uses IPv6 uses 88 kb/s of bandwidth. Cisco Unified CM 8.0 also supports a type of locations-based, topology-unaware call admission control know as call counting. In order to enable call counting in Unified CM Administration, select Service Parameters > Clusterwide Parameters (Call Admission Control). The default setting for Call Counting CAC Enabled is False. The voice and video bandwidth values for call counting are configurable.

    cucmipv6-04.gif

Cisco Unified IP Phones

This section describes use cases for IPv4 and IPv6 calls between the phone and Cisco Unified Communications Manager. See the following use cases, which assume that Cisco Unified Communications Manager can listen on the correct port, that an MTP is available to translate IP address versions, and that the device has the correct address version:

  1. Phone Has IP Addressing Mode of IPv4 Only—If the IP Addressing Mode for the phone is IPv4 Only, the phone connects to Cisco Unified Communications Manager by using an IPv4 address. Signaling and media negotiation occurs by using an IPv4 address. If an IPv4 address is not available for the phone, the user cannot make calls.

  2. Phone Has IP Addressing Mode of IPv6 Only —If the IP Addressing Mode for the phone is IPv6 Only and you set the Enable IPv6 enterprise parameter to True, the phone uses a global scope or unique local scope IPv6 address to connect to Cisco Unified Communications Manager. Signaling and media negotiation occur by using this IPv6 address. If an IPv6 address is not available for the phone, the user cannot make calls. Likewise, if an IPv6 address is not configured for the phone, the phone cannot register with Cisco Unified Communications Manager.

  3. Phone Has IP Addressing Mode of IPv4 and IPv6 —If the IP Addressing Mode for the phone is IPv4 and IPv6 and you set the Enable IPv6 enterprise parameter to True, Cisco Unified Communications Manager considers the IP address support for the phone and the configuration for IP Addressing Mode Preference for Signaling setting before connecting the call. If only one IP address version is available on the phone, the phone uses the address that is available to connect to Cisco Unified Communications Manager for signaling negotiation. If both IP addresses types are available on the phone, the phone uses the configuration for the IP Addressing Mode for Signaling setting for signaling negotiation.

DHCPv6

DHCPv6, which is the version of Dynamic Host Configuration Protocol that supports IPv6, can assign an IPv6 address and other network settings to the phone after you connect it to the network. In addition, DHCPv6 can assign an IPv6 address to the Cisco Unified Communications Manager server; that is, if you do not plan to assign a static IP address to the server. (Cisco recommends that you assign a static IP address to the server.)

DNS

For IPv6, DNSv6 handles the AAAA record, which can map IPv6 addresses. For IPv4, DNS handles the A record, which can map IPv4 addresses.

cucmipv6-05.gif

Gateways

MGCP and H.323 gateways do not support IPv6. In order to communicate with IPv6 devices that connect to these gateways, Cisco Unified Communications Manager inserts an MTP that can translate IPv4 to IPv6 during a call. The Cisco ATA 186 and 188 Analog Telephone Adaptors do not support IPv6. Analog phone gateways can operate in IPv4 only, IPv6 only, or IPv4 and IPv6 (dual-stack mode).

Cisco IOS SIP gateways can support IPv6 only, IPv4 only, or IPv4 and IPv6 simultaneously in dual-stack mode. Before Cisco Unified Communications Manager can interact with these gateways, you must configure it in the SIP Trunk Configuration window in Cisco Unified Communications Manager Administration.

Media Termination Points

Cisco IOS MTP supports media interoperation between IPv4 and IPv6 networks. Cisco IOS MTP for IPv4-to-IPv6 media translation operates only in dual-stack mode. In Cisco Unified Communications Manager Administration, only the IOS Enhanced Media Termination Point option for MTPs (Media Resources > Media Termination Point) and transcoders (Media Resources > Transcoders) support the translation functionality; that is, the software MTP component in the Cisco IP Voice Media Streaming Application does not support IPv4 to IPv6 translation.

The following Cisco IOS configuration is an example of a software MTP. The sccp local GigabitEthernet0/0 command associates the IPv4 and IPv6 addresses on this interface with the MTP for both SCCP signaling and media addresses.

interface GigabitEthernet0/0
ip address 192.168.1.5 255.255.255.0
! MTP's IPv4 address
ipv6 address 2001:0db8:10:1:1::5/64
! MTP's IPv6 address
!
sccp local GigabitEthernet0/0
sccp ccm 192.168.0.15 identifier 1 version 7.0
! Unified CM's IPv4 address
sccp ccm 2001: 0db8:10:1::15 identifier 2 version 7.0
! Unified CM's IPv6 address
sccp
!
sccp ccm group 1
associate ccm 1 priority 1
associate ccm 2 priority 2
associate profile 1 register MTP-1
!
dspfarm profile 1 mtp
codec g711ulaw
codec pass-through
maximum sessions software 100
associate application SCCP
!

SIP Trunks

Cisco Unified CM supports two IPv6 devices, IP phones and SIP trunks (to gateways or other Unified CM clusters). Rather than add IPv6 configuration parameters to specific trunks and phones, a Unified CM configuration template contains IPv6-specific configuration parameters for phones and SIP trunks. This section describes that template, which is known as the common device configuration. The common device configuration profile (Device > Device Settings > Common Device Configuration) contains the following IPv6 configuration information:

cucmipv6-06.gif

If configured appropriately, SIP trunks can interact with devices that support IPv4 only, IPv6 only, or IPv4 and IPv6. Similar to Cisco Unified Communications Manager and other components, the SIP trunk uses the configuration for the Enable IPv6 enterprise parameter to determine whether to support devices that use IPv6. See the following sections:

  • IPv4 or IPv6 Signaling for SIP Trunks—These factors determine whether to use IPv4 or IPv6 for signaling events for SIP trunks:

    • The direction of the call

    • IP Addressing Mode for the SIP trunk, as configured in the Common Device Configuration window and applied to the trunk

    • IP Addressing Mode Preference for Signaling configuration for the SIP trunk, as configured in the Common Device Configuration window (or Enterprise Parameter Configuration window) and applied to the trunk

      (Device > Device Settings > Common Device Configuration)

    • Configured Destination Address(es) for the SIP trunk

    If you configure only one destination address, that is, either the Destination Address, which supports IPv4, or the Destination IPv6 Address, which supports IPv6, ensure that the IP Addressing Mode that you configure for the SIP trunk matches the IP address type that you configured for the destination address. If the configuration does not match, no call gets established over the trunk. If you configure both the Destination Address and the Destination IPv6 Address, make sure that you configure the IP Addressing Mode as IPv4 and IPv6, so the trunk is in dual-stack mode. For a dual-stack trunk, the IP Addressing Mode Preference of Signaling configuration that you applied to the SIP trunk determines whether IPv4 or IPv6 gets used for signaling events for outgoing calls over SIP trunks.

    This screenshot shows the SIP Route Pattern Configuration in Unified CM:

    cucmipv6-07.gif

  • IPv4 or IPv6 Media for SIP Trunks—These factors determine whether to use IPv4 or IPv6 for media events for SIP trunks:

    • The direction of the call

    • Whether the call is an early offer or delayed offer call

    • IP address preference in the SDP offer

    • IP Addressing Mode for the SIP trunk, as configured in the Common Device Configuration window and applied to the trunk

    • Configuration for the IP Addressing Mode Preference for Media enterprise parameter, as configured in the Enterprise Parameter Configuration window For media negotiation for dual-stack devices, Cisco Unified Communications Manager dynamically determines the IP address to use for the call; that is, if any device on the call only supports one IP version, that IP version gets use, and an MTP that can translate IP versions gets inserted into the call. If all devices on the call support both IP versions, the configuration for the IP Addressing Mode Preference for Media enterprise parameter gets used.

    • Configuration for the Enable ANAT check box (and whether ANAT is required or supported in the INVITE)

      ANAT is used in the SIP Offer and Answer exchange between dual-stack SIP trunks. ANAT allows SIP devices to send both IPv4 and IPv6 addresses in the Session Description Protocol (SDP) body of a SIP Offer, and to return in the SDP body of the SIP Answer a preferred IP address (IPv4 or IPv6) with which to establish a media connection. Cisco supports ANAT over dual-stack (IPv4 and IPv6) SIP trunks. ANAT must be supported by both ends of the SIP trunk. In order to enable ANAT, check the Enable ANAT check box on the SIP Profile associated with the SIP trunk . ANAT can be used with both Early Offer and Delayed Offer calls. Select Device > Device Settings > SIP Profile in Unified CM Administration.

      cucmipv6-08.gif

    • IP Addressing Mode for the phone

In order to configure SIP trunks to gateways and Unified CM SIP intercluster trunks, select Devices > Trunks > SIP Trunk in Unified CM Administration.

cucmipv6-09.gif

The SIP trunk configuration settings discussed in this section are applied through the Common Device Configuration profile that is created and assigned to the SIP trunk (IP Addressing Mode and IP Addressing Mode Preference for Signaling), and through the SIP Profile configuration assigned to the SIP trunk (Enable ANAT).

TFTP Server

The TFTP server uses IPv4 to communicate with most components, such as the database, in Cisco Unified Communications Manager. If configured appropriately, the TFTP server can communicate with devices that use IPv4, IPv6, or both types of addresses. Running in dual-stack mode, the TFTP server can respond to file requests from both IPv4 and IPv6 networks. For requests from IPv4 networks, the TFTP server responds by using an IPv4 stack. For requests from IPv6 networks, the TFTP server responds by using an IPv6 stack; that is, if you set the Enable IPv6 enterprise parameter to True. IPv6 support applies to TFTP requests from devices, and HTTP requests from off-cluster TFTP servers where the local TFTP server is configured as their alternate file server.

The TFTP server uses the configuration for the Enable IPv6 enterprise parameter to determine how to communicate with the phone. If you set the Enable IPv6 enterprise parameter to False, the TFTP server uses IPv4 to communicate with the phone. If you set the parameter to True, the TFTP server uses IPv4 or IPv6, depending on the IP Addressing Mode for the phone. If the configuration changes for the Enable IPv6 enterprise parameter, the TFTP server receives a change notification with the new configuration, and the TFTP server enables or disables its IPv6 capabilities without requiring you to restart the Cisco TFTP service.

The configuration file that the TFTP server serves to the phone contains the configuration for these settings:

  • IP Addressing Mode, IP Addressing Mode Preference for Signaling, and Allow Auto-Configuration for the Phone

  • Host Name/IP Address (IPv4 setting) for the Cisco Unified Communications Manager server

  • IPv6 Name for the Cisco Unified Communications Manager server (only if you set the Enable IPv6 enterprise parameter to True)

  • IPv6 address for the CAPF server (only if you set the Enable IPv6 enterprise parameter to True and activate the Cisco Certificate Authority Proxy Function service)

Related Information

Updated: May 18, 2011
Document ID: 112997