Cisco 7962G Administration Guide - Page 158

General Troubleshooting Tips Chapter 9 Troubleshooting and Maintenance Table 9-1 Cisco Unified IP Phone Security Troubleshooting (continued) Problem Possible Cause Phone cannot obtain a DHCP-assigned IP address Phone does not register with Cisco Unified Communications Manager These errors typically indicate that 802.1X is not enabled on the phone. To enable it, see the "Security Configuration Menu" section on page 4-21 for information on enabling 802.1X on the phone. Phone status display as "Configuring IP" or "Registering" 802.1X Authentication Status displays as "Disabled" (see the "802.1X Authentication and Status" section on page 4-29). Status menu displays DHCP status as timing out (see the "Call Statistics Screen" section on page 7-12). Factory Reset Deleted 802.1X Shared Secret Phone cannot obtain a DHCP-assigned IP address Phone does not register with Cisco Unified Communications Manager Phone status display as "Configuring IP" or "Registering" Cannot access phone menus to verify 802.1X status These errors typically indicate that the phone has completed a factory reset while 802.1X was enabled. A factory reset deletes the shared secret, which is required for 802.1X authentication and network access. To resolve this, you have two options: • Temporarily disable 802.1X on the switch. • Temporarily move the phone to a network environment that is not using 802.1X authentication. Once the phone starts up normally in one of these conditions, you can access the 802.1X configuration menus and re-enter the shared secret. General Troubleshooting Tips Table 9-2 provides general troubleshooting information for the Cisco Unified IP Phone. Table 9-2 Cisco Unified IP Phone Troubleshooting Summary Explanation Connecting a Cisco Unified IP Phone to another Cisco Unified IP Phone/ Cisco does not support connecting an IP phone to another IP phone through the PC port. Each IP phone should directly connect to a switch port. If phones are connected together in a line (by using the PC port), the phones will not work. Poor quality when calling digital cell phones using the G.729 protocol. In Cisco Unified Communications Manager, you can configure the network to use the G.729 protocol (the default is G.711). When using G.729, calls between an IP phone and a digital cellular phone will have poor voice quality. Use G.729 only when absolutely necessary. Prolonged broadcast storms cause A prolonged Layer 2 broadcast storm (lasting several minutes) on the voice IP phones to reset, or be unable to make or VLAN may cause IP phones to reset, lose an active call, or be unable to initiate answer a call. or answer a call. Phones may not come up until a broadcast storm ends. 9-10 Cisco Unified IP Phone 7962G and 7942G Administration Guide for Cisco Unified Communications Manager 6.1 OL-14625-01