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This chapter provides information that can assist you in troubleshooting problems with your Cisco Unified IP Phone or with your IP telephony network. It also explains how to maintain your voice network and clean your phone.
If you need additional assistance to resolve an issue, see Documentation, Support, and Security Guidelines.
This chapter includes these topics:
After you install a Cisco IP Phone into your network and add it to Cisco Unified Communications Manager, the phone should start up as described in the related topic below.
If the phone does not start up properly, see the following sections for troubleshooting information.
When you connect a Cisco IP Phone to the network port, the phone does not go through the normal startup process as described in the related topic and the phone screen does not display information.
If the phone does not go through the startup process, the cause may be faulty cables, bad connections, network outages, lack of power, or the phone may not be functional.
To determine whether the phone is functional, use the following suggestions to eliminate other potential problems.
Verify that the network port is functional:
Exchange the Ethernet cables with cables that you know are functional.
Disconnect a functioning Cisco IP Phone from another port and connect it to this network port to verify that the port is active.
Connect the Cisco IP Phone that does not start up to a different network port that is known to be good.
Connect the Cisco IP Phone that does not start up directly to the port on the switch, eliminating the patch panel connection in the office.
Verify that the phone is receiving power:
If the phone still does not start up properly, power up the phone with the handset off-hook. When the phone is powered up in this way, it attempts to launch a backup software image.
If the phone still does not start up properly, perform a factory reset of the phone.
After you attempt these solutions, if the phone screen on the Cisco IP Phone does not display any characters after at least five minutes, contact a Cisco technical support representative for additional assistance.
If the phone proceeds past the first stage of the startup process (LED buttons flashing on and off) but continues to cycle through the messages that displays on the phone screen, the phone is not starting up properly. The phone cannot successfully start up unless it connects to the Ethernet network and it registers with a Cisco Unified Communications Manager server.
In addition, problems with security may prevent the phone from starting up properly. See Troubleshooting Procedures for more information.
While the phone cycles through the startup process, you can access status messages that might provide you with information about the cause of a problem. See Display Status Messages Window section for instructions about accessing status messages and for a list of potential errors, their explanations, and their solutions.
If the network is down between the phone and either the TFTP server or Cisco Unified Communications Manager, the phone cannot start up properly.
The IP addressing and routing fields may not be configured correctly.
You should verify the IP addressing and routing settings on the phone. If you are using DHCP, the DHCP server should provide these values. If you have assigned a static IP address to the phone, you must enter these values manually.
If the Cisco Unified Communications Manager or TFTP services are not running, phones may not be able to start up properly. In such a situation, it is likely that you are experiencing a systemwide failure, and other phones and devices are unable to start up properly.
If the Cisco Unified Communications Manager service is not running, all devices on the network that rely on it to make phone calls are affected. If the TFTP service is not running, many devices cannot start up successfully. For more information, see Start Service.
If you continue to have problems with a particular phone that other suggestions in this chapter do not resolve, the configuration file may be corrupted.
The phone is not registered with the Cisco Unified Communications Manager
A Cisco IP Phone can register with a Cisco Unified Communications Manager server only if the phone is added to the server or if autoregistration is enabled. Review the information and procedures in Phone Addition Methods to ensure that the phone is added to the Cisco Unified Communications Manager database.
To verify that the phone is in the Cisco Unified Communications Manager database, choose from Cisco Unified Communications Manager Administration. Click Find to search for the phone based on the MAC Address. For information about determining a MAC address, see Determine Phone MAC Address.
If the phone is already in the Cisco Unified Communications Manager database, the configuration file may be damaged. See Configuration File Corruption for assistance.
If a phone cannot obtain an IP address when it starts up, the phone may not be on the same network or VLAN as the DHCP server, or the switch port to which the phone connects may be disabled.
Ensure that the network or VLAN to which the phone connects has access to the DHCP server, and ensure that the switch port is enabled.
If users report that their phones are resetting during calls or while the phones are idle, you should investigate the cause. If the network connection and Cisco Unified Communications Manager connection are stable, a phone should not reset.
Typically, a phone resets if it has problems in connecting to the network or to Cisco Unified Communications Manager.
Verify that the Ethernet connection to which the Cisco IP Phone connects is up. For example, check whether the particular port or switch to which the phone connects is down and that the switch is not rebooting. Also ensure that no cable breaks exist.
Intermittent network outages affect data and voice traffic differently. Your network might be experiencing intermittent outages without detection. If so, data traffic can resend lost packets and verify that packets are received and transmitted. However, voice traffic cannot recapture lost packets. Rather than retransmitting a lost network connection, the phone resets and attempts to reconnect to the network. Contact the system administrator for information on known problems in the voice network.
Verify that you have properly configured the phone to use DHCP. Verify that the DHCP server is set up properly. Verify the DHCP lease duration. We recommend that you set the lease duration to 8 days.
The static IP address assigned to the phone may be incorrect.
If the phone is assigned a static IP address, verify that you have entered the correct settings.
If the phone appears to reset during heavy network usage, 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 you are not the only administrator with access to Cisco Unified Communications Manager, you should verify that no one else has intentionally reset the phones.
You can check if a Cisco IP Phone received a command from Cisco Unified Communications Manager to reset by pressing Applications on the phone and choosing .
If the Restart Cause field displays Reset-Reset, the phone receives a Reset/Reset from Cisco Unified Communications Manager Administration.
If the Restart Cause field displays Reset-Restart, the phone closed because it received a Reset/Restart from Cisco Unified Communications Manager Administration.
The phone reset continues and you suspect DNS or other connectivity issues.
If the phone continues to reset, eliminate DNS or other connectivity errors by following the procedure in Determine DNS or Connectivity Issues.
In most cases, a phone restarts if it powers up by using external power but loses that connection and switches to PoE. Similarly, a phone may restart if it powers up by using PoE and then connects to an external power supply.
The following sections provide troubleshooting information for the security features on the Cisco IP Phone. For information about the solutions for any of these issues, and for additional troubleshooting information about security, see Cisco Unified Communications Manager Security Guide.
801.1X authentication problems can be broken into the categories that are described in the following table.
If all the following conditions apply, | See |
---|---|
These errors typically indicate that 802.1X authentication is enabled on the phone, but the phone is unable to authenticate.
To resolve this problem, check the 802.1X and shared secret configuration. See Identify 802.1X Authentication Problems.
These errors typically indicate that 802.1X authentication is not enabled on the phone.
If 802.1X is not enabled on the phone, see 802.1X Authentication section.
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 situation, temporarily move the phone to a network environment that is not using 802.1X authentication. After the phone starts up normally, access the 802.1X configuration menus to enable device authentication and to reenter the shared secret. See 802.1X Authentication section for details.
The following sections describe how to resolve audio and video problems.
When at least one person in a call does not receive audio, IP connectivity between phones is not established. Check the configuration of routers and switches to ensure that IP connectivity is properly configured.
Check the AvgJtr and the MaxJtr statistics. A large variance between these statistics might indicate a problem with jitter on the network or periodic high rates of network activity.
Poor quality occurs with tandem audio encoding. Tandem encoding can occur when calls are made between an IP Phone and a digital cellular phone, when a conference bridge is used, or in situations where IP-to-IP calls are partially routed across the PSTN.
In these cases, use of voice codecs such as G.729 and iLBC may result in poor voice quality.
Use the G.729 and iLBC codecs only when absolutely necessary.
The display appears to have rolling lines or a wavy pattern.
The phone might be interacting with certain types of older fluorescent lights in the building.
Move the phone away from the lights or replace the lights to resolve the problem.
The following sections help troubleshoot general telephone call problems.
The phone does not have a DHCP IP address, is unable to register to Cisco Unified Communications Manager. Phones with an LCD display show the message Configuring IP or Registering. Phones without an LCD display play the reorder tone (instead of dial tone) in the handset when the user attempts to make a call.
The user complains that numbers are missed or delayed when the keypad is used.
Pressing the keys too quickly can result in missed or delayed digits.
Users report frequent Not enough bandwidth messages on their phones.
The Cisco Unified Communications Manager does not have adequate bandwidth to place the call or there are policy restrictions.
For information on changing the Cisco Unified Communications Manager bandwidth, see the documentation for your particular version of Cisco Unified Communications Manager.
These procedures can be used to identify and correct problems.
Step 1 | On the Cisco IP Phone, press Applications . |
Step 2 | Select
, and look at the following
options:
|
Step 3 | If you are
using DHCP, check the IP addresses that your DHCP server distributes.
See the Understanding and Troubleshooting DHCP in Catalyst Switch or Enterprise Networks document, available at this URL: http://www.cisco.com/en/US/tech/tk648/tk361/technologies_tech_note09186a00800f0804.shtml |
Note | A service must be activated before it can be started or stopped. |
Step 1 | Use the Reset Settings menu to reset phone settings to their default values. |
Step 2 | Modify DHCP and IP settings: |
Step 3 | 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. |
Step 4 | From Cisco Unified Communications Manager, choose and verify that reference to the server is made by the IP address and not by the DNS name. |
Step 5 | From Cisco Unified Communications Manager, choose Find to search for this phone. Verify that you have assigned the correct MAC address to this Cisco IP Phone. . Click |
Step 6 | Power cycle the phone. |
If you have additional questions about troubleshooting your phone, go to the following Cisco website and navigate to the desired phone model: