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Cisco Unified IP Phone 8941 and 8945 Administration Guide for Cisco Unified Communications Manager 8.5 (SCCP and SIP)
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Chapter
Understanding Interactions with Other Cisco Unified IP Telephony 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
• Configuration file via TFTP service
• Authentication and encryption (if configured for the telephony system)
• 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 CM to work with the IP devices described in this
chapter, go to the Cisco Unified IP Phone Configuration chapter in the Cisco Communications Manager
Administration 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 1-9.
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
For more information, refer to “Software Upgrades” chapter in the Cisco Unified Communications
Operating System Administration Guide.
Related Topic
• Telephony Features Available for the Cisco Unified IP Phone, page 5-1
Understanding How the Cisco Unified IP Phone Interacts with the VLAN
The Cisco Unified IP Phone 8941 and 8945 have 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 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.