Cisco Systems ATA187I1ARF Manual De Usuario

The ATA 187 sends messages with request type 151 to renew the DHCP address leases. If the DHCP 
server expects messages with request type 150, the lease will be denied, forcing the ATA 187 to restart 
and request a new IP address from the DHCP server.

If the phone has been assigned a static IP address, verify that you have entered the correct settings. See 

 for more information.

If the ATA 187 appears to reset during heavy network usage (for example, following extensive web 
surfing on a computer connected to same switch as phone), it is likely that you do not have a voice VLAN 
configured.

Isolating the phones on a separate auxiliary VLAN increases the quality of the voice traffic.

If the phone continues to reset, follow these steps to eliminate DNS or other connectivity errors:

Use the IVR to reset phone settings to their default values. See 

 for details.

Modify DHCP and IP settings:

Disable DHCP. 

Assign static IP values to the phone. See 

 for 

instructions. Use the same default router setting used for other functioning ATA 187.

Assign TFTP server. Use the same TFTP server used for other functioning ATA 187.

On the Cisco Unified Communications Manager server, verify that the local host files have the correct 
Cisco Unified Communications Manager server name mapped to the correct IP address.

From Cisco Unified Communications Manager, choose System > Server and verify that the server is 
referred to by its IP address and not by its DNS name.

From Cisco Unified Communications Manager, choose Device > Phone and verify that you have 
assigned the correct MAC address to this Cisco Unified IP Phone. For information about determining a 
MAC address, see 

Power cycle the phone.