Cisco 7821, Руководство администратора

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• Dynamic Host Configuration Protocol (DHCP)—Enables the phone to receive an IP address from the
network DHCP server. The Cisco IP phone typically operates in a network where a DHCP server assigns
IP addresses to devices. Because IP addresses are a limited resource, the DHCP server periodically renews
the device lease on the IP address. If a phone loses the IP address for any reason, or if some other device
on the network is assigned the same IP address, the communication between the SIP proxy and the phone
is either severed or degraded. Whenever an expected SIP response is not received within a programmable
amount of time after the corresponding SIP command is sent, the DHCP Timeout on Renewal parameter
causes the device to request a renewal of its IP address. If the DHCP server returns the IP address that
it originally assigned to the phone, the DHCP assignment is presumed to be operating correctly. Otherwise,
the phone resets to try to fix the issue.
• Static IP—A static IP address for the phone.
Before you begin
Access the phone administration web page. See Access the Phone Web Page, on page 80 .
Procedure
Step 1 Select Voice > System .
Step 2
In the IPv4 Settings section, use the Connection Type drop-down list box to choose the connection type:
• Dynamic Host Configuration Protocol (DHCP)
• Static IP
Step 3
In the IPv6 Settings section, use the Connection Type drop-down list box to choose the connection type:
• Dynamic Host Configuration Protocol (DHCP)
• Static IP
Step 4
If you choose Static IP, configure these settings in the Static IP Settings section:
• Static IP —Static IP address of the phone
• NetMask —Netmask of the phone
•
Gateway
—Gateway IP address
Step 5 Click Submit All Changes .
DHCP Option Support
The following table lists the DHCP options that are supported on the Cisco IP Phone.
Description Network Standard
Subnet mask DHCP option 1
Time offset DHCP option 2
Cisco IP Phone 7800 Series Multiplatform Phones Administration Guide
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Cisco IP Phone Administration
DHCP Option Support