Cisco Systems 7940G, 7960G manual Providing Power to the Cisco Unified IP Phone, Related Topics

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

Providing Power to the Cisco Unified IP Phone

Understanding How the Cisco Unified IP Phone Interacts with the VLAN

The Cisco Unified IP Phone 7960G and 7940G have an internal Ethernet switch, enabling proper forwarding of appropriate packets to the phone, to the access port (labeled 10/100 PC on the phone), and to the network port (labeled 10/100 SW on 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 share the same port on the switch. This shared physical link has the following implications for the VLAN configuration on the network:

•The current VLANs might be configured on an IP subnet basis. However, additional IP addresses might not be available to assign the phone to the same subnet as other devices connected to the same port.

•Data traffic present on the VLAN supporting phones might reduce the quality of Voice-over-IP 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)

•Data traffic to and from the PC connected to the switch through the access port of the IP phone (native VLAN)

Isolating the phones on a separate, auxiliary VLAN increases the quality of the voice traffic and allows a large number of phones to be added to an existing network where there are not enough IP addresses for each phone.

For more information, refer to the documentation included with a Cisco switch. You can also access related documentation at this URL:

http://www.cisco.com/univercd/cc/td/doc/product/lan/index.htm

Related Topics

•Understanding the Phone Startup Process, page 2-6

•Network and Access Ports, page 3-3

•Network Configuration Menu, page 4-4

Providing Power to the Cisco Unified IP Phone

The Cisco Unified IP Phone 7960G and 7940G can be powered with external power or with Power over Ethernet (PoE). External power is provided through a separate power supply. PoE is provided by a switch through the Ethernet cable attached to a phone.

Note When you install a phone that is powered with external power, connect the power supply to the phone and to a power outlet before you connect the Ethernet cable to the phone. When you remove a phone that is powered with external power, disconnect the Ethernet cable from the phone before you disconnect the power supply.

Cisco Unified IP Phone 7960G/7940G Administration Guide for Cisco Unified Communications Manager 7.0 (SCCP)