Cisco Systems 8.6 manual General Troubleshooting Tips, Explanation

Chapter 9 Troubleshooting and Maintenance

General Troubleshooting Tips

Table 9-1 Cisco Unified IP Phone Security Troubleshooting (continued)

Problem

Possible Cause

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.

After 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 9-2provides 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		Cisco does not support connecting an IP Phone to another IP Phone through the
	another Cisco Unified IP Phone		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		In Cisco Unified Communications Manager, you can configure the network to
	phones using the G.729 protocol		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.
	Moving a network connection from the		If you are powering your phone through the network connection, you must be
	phone to a workstation		careful if you decide to unplug the phone’s network connection and plug the
			cable into a desktop computer.
			Caution The network card in the computer cannot receive power through the
				network connection; if power comes through the connection, the
				network card can be destroyed. To protect a network card, wait
				10 seconds or longer after unplugging the cable from the phone
				before plugging it into a computer. This delay gives the switch
				enough time to recognize that there is no longer a phone on the line
				and to stop providing power to the cable.
	Changing the telephone configuration		By default, the network configuration options are locked to prevent users from
			making changes that could impact their network connectivity. You must unlock
			the network configuration options before you can configure them. See
			Unlocking and Locking Options, page 4-2for details.
		Cisco Unified IP Phone Administration Guide for Cisco Unified Communications Manager 8.6 (SCCP and SIP)
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