Cisco Systems OL-23089-01 Understanding How the Cisco Unified IP Phone Interacts with the VLAN

Chapter 2 Preparing to Install the Cisco Unified IP Phone on Your Network

Understanding Interactions with Other Cisco Unified IP Communications Products

Understanding How the Cisco Unified IP Phone Interacts with Cisco Unified CM

Cisco Unified CM is an open and industry-standard call processing system. Cisco Unified CM software sets up and tears down calls between phones, integrating traditional PBX functionality with the corporate IP network. Cisco Unified CM manages the components of the IP telephony system—the phones, the access gateways, and the resources necessary for features such as call conferencing and route planning. Cisco Unified CM also provides:

•Firmware for phones

•Authentication and encryption (if configured for the telephony system)

•Configuration, CTL, and Identity Trust List (ITL) files via the TFTP service

•Phone registration

•Call preservation, so that a media session continues if signaling is lost between the primary CM and a phone

For information about configuring Cisco Unified Communications Manager to work with the IP devices described in this chapter, refer to Cisco Unified Communications Manager Administration Guide, Cisco Unified Communications Manager System Guide, and Cisco Unified Communications Manager Security Guide.

For an overview of security functionality for the Cisco Unified IP Phone, see the “Understanding Security Features for Cisco Unified IP Phones” section on page 1-11.

Note If the Cisco Unified IP Phone model that you want to configure does not appear in the Phone Type drop-down list in Cisco Unified CM Administration, go to the following URL and install the latest support patch for your version of Cisco Unified CM: http://www.cisco.com/kobayashi/sw-center/sw-voice.shtml

Related Topic

•Telephony Features Available for the Phone, page 5-2

Understanding How the Cisco Unified IP Phone Interacts with the VLAN

The Cisco Unified IP Phone 7931G has an internal Ethernet switch, enabling forwarding of packets to the phone, and to the access port and the network port on the back of the phone.

If a computer is connected to the access port, the computer and the phone share the same physical link to the switch and the same switch port. This shared physical link has these implications for the network VLAN configuration:

•Although the current VLANs may be configured on an IP subnet basis, additional IP addresses may not be available to assign the phone to the same subnet as other devices that connect to the same port.

•Data traffic present on the data/native VLAN may reduce the quality of VoIP traffic.

•Network security may indicate a need to isolate the VLAN voice traffic from the VLAN data traffic.

You can resolve these issues by isolating the voice traffic onto a separate VLAN. The switch port that the phone is connected to would be configured to have separate VLANs for carrying:

•Voice traffic to and from the IP phone (auxiliary VLAN, on the Cisco Catalyst 6000 series, for example)

Cisco Unified IP Phone 7931G Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)

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