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The Implementation phase of your network deployment is an excellent time to develop a methodology for troubleshooting the network as a whole. Troubleshooting networking equipment at a system level requires solid detective skills. When a problem occurs, the list of potential suspects is long. You must collect detailed information and systematically narrow the list of potential causes to determine the root problem. This topic does not provide step-by-instructions for resolving problems that occur during network installation. Instead, this topic describes sound methods for troubleshooting your network using the following general steps:
1. Gather Information on the Problem.
2. Isolate Point(s) of Failure.
3. Apply Tools to Determine the Problem's Root Cause.
Gather Information on the Problem
In a IP telephony network, problems are typically discovered and reported by one of the following types of users:
•External users trying to reach employees within your company
•Internal users using phones to call employees in other company locations or PSTN destinations, and perform basic actions such as call transfers and dialing into conferences.
As the network administrator, you must collect sufficient information from these users to allow you to isolate the problem. Detailed, accurate information will make this task easier. Table 3 lists recommended questions to ask users when they report a problem. As you turn up your network, you may consider putting these questions in an on-line form. A form will encourage users to provide more details about the problem and also put them into the habit of looking for particular error messages and indicators. Capturing the information electronically will also permit you to retrieve and re-examine this information in the future, should the problem repeat itself.
Table 3 Questions to Ask Users When They Report Problems
Ask this Question... | To Determine... |
Did something fail or did it simply perform poorly? | Whether the issue relates to system degradation or a connectivity failure. An example of a failure is when a user dials a phone number and hears fast busy tone. An example of a performance problem is when a user dials into a conference call and hears "choppy" audio when other parties speak. Quality of service or performance issues require a different approach than connectivity or operational problems. You must still isolate the potential sources of the problem, but you will typically use performance management tools instead of log files. |
What device were you trying to use? | The device type, model and version of software installed. It is also critical to capture the IP address assigned to the device, as well as its MAC address. If the case of IP phones, determining the phone's active Cisco Unified Communications Manager server is also important. On Cisco Unified IP phones, these important network values can be displayed by pressing the Settings button and choosing the Network Configuration option from the menu. |
Did it ever work? | If a device was recently installed and the problem occurred while making it work for the first time, or if the device was operating normally before the problem occurred. If the device was newly installed, the problem is most likely due to improper configuration or wiring of that particular device. Problems with devices that are already up and running can typically be traced back to one of two causes: (a) the user modifying their device, such as changing their configuration or upgrading software, or (b) a change or failure elsewhere in the network. |
Exactly what action(s) did you perform? | The steps that led up to the problem, including which buttons were pressed and in which order. Capturing this information in detail is important so that you can consistently reproduce the problem. |
What error message(s) appeared or announcements did you hear? | The visual and audio indicators of the problem. Ask users to provide the exact text that appears and any error codes in either an E-mail or on-line form. If the error indication was audible, ask the user to write down the announcement they heard, the last menu option they were able to successfully choose or the tone they heard when the call failed. |
What time did the problem occur? | The date and time to compare against entries in log files. If the problem occurred on a Cisco Unified IP phone, make certain the user provides the timestamp that appears on their phone's display. Several Cisco components in a network may capture the same problem event in separate log files, with different ID values. In order to correlate log entries written by different components, you must compare the timestamps to find messages for the same event. Cisco Unified IP phones synchronize their date and time with their active Cisco Unified Communications Manager server. If all Cisco components in the network use Network Time Protocol (NTP) to synchronize with the same source, then the timestamps for the same problem messages will match in every log file. |
What is the number of the phone you used and what was the phone number you called? | If the problem relates to a WAN or PTSN link, or a Cisco Unified Communications Manager dial plan issue. Ask the user the phone number he or she dialed (called number) and determine if the destination was within his or her site, another site within the corporate network, or a PSTN destination. Because the calling number (the number of the phone used) also affects call routing in some cases, capture this number as well. |
Did you try to perform any special actions, such as a transfer, forward, call park, call pickup, or meet-me conference? Is the phone set up to automatically perform any of these actions? | If the problem is not directly related to the calling number or called number but rather to the supplementary service setup on Unified Communications Manager or the problem is at the destination phone the user tried to reach by transferring or forwarding the call. |
Did you attempt the same action on another device? | If the problem is isolated to that user's device or represents a more widespread network problem. If the user cannot make a call from his or her phone, ask the user to place a call to the same destination using a phone in a nearby office. |
Isolate Point(s) of Failure
After collecting information on the symptoms and behavior of the problem, to narrow the focus of your efforts you should:
•Identify the specific devices involved in the problem.
•Check the version of software running on each device.
•Determine if something has changed in the network.
•Verify the integrity of the IP network.
Identify Devices Involved in the Problem
In large- to medium-sized networks, it is crucial to identify the specific phones, routers, switches, servers and other devices that were involved in a reported problem. Isolating these devices allows you to rule out the vast majority of equipment within the network and focus your time and energy on suspect devices. To help you isolate which devices were involved in a problem, two types of information can prove invaluable:
•Network topology diagrams: It is strongly recommended that you have one or more diagrams that show the arrangement of all Cisco Unified Communications products in your network. These diagrams illustrate how these devices are connected and also capture each device's IP address and name (you may want to also have a spreadsheet or database of the latter information). This information can help you visualize the situation and focus on the devices that may be contributing to the reported problem. See Network Topology Diagrams for recommendations on how to prepare these diagrams.
•Call flow diagrams: Cisco equipment, including Unified Communications Manager servers, typically provide detailed debug and call trace log files. To interpret these log files, however, it is useful to understand the signaling that occurs between devices as calls are set up and disconnected. Using the network topology and call flow diagrams in conjunction with the log files, you can trace how far a call progressed before it failed and identify which device reported the problem. Examples of using call flow diagrams for problem isolation are shown in Troubleshooting Daily Operations.
Check Software Release Versions for Compatibility
After you have identified which devices may be involved in the problem, verify that the version of software running on each device is compatible with the software running on every other device. As part of Cisco Unified Communications Release 6.0(1) verification, Cisco Systems has performed interoperability and load testing on simulated network environments running specific software versions. The Release Matrix lists the combination of software releases that were tested.
However, if the combination of releases installed in your network does not match the values in the Release Matrix, it does not necessarily mean the combination is invalid. To check interoperability for a specific device and software release, locate and review its Release Notes. Release Notes contain up-to-date information on compatibility between the product and various releases of other products. This document also describes open caveats, known issues that may cause unexpected behavior. Before beginning extensive troubleshooting work, examine the Release Notes to determine if you are experiencing a known problem that has an available workaround.
Tip The Bug Toolkit requires that you are a Cisco partner or a registered Cisco.com user with a Cisco service contract. Using the Bug Toolkit, you can find caveats for any release. To access the Bug Toolkit, go to the http://tools.cisco.com/Support/BugToolKit/ .
Determine if Network Changes Have Occurred
Before focusing on the particular device or site where the problem occurred, it may be useful to determine if a change was made to surrounding devices. If something has been added, reconfigured or removed from elsewhere in the network, that change may be the source of the problem. It is recommended that you track changes to the IP telephony network such as:
•New user phones added
•Modifications to Cisco Unified Communications Manager call routing settings, such as new directory numbers, route patterns and dial rules to support new sites or devices
•Changes to port configurations on switches, routers or gateways (new equipment, wiring changes or new port activation)
•Changes to IP addressing schemes (such as adding new subnets) that may have affected route tables
Verify the IP Network Integrity
Always remember that Cisco Unified Communications equipment relies on a backbone IP network. Many connectivity problems are not caused by configuration errors or operational failures on Cisco devices, but rather by the IP network that interconnects them. Problems such as poor voice quality are typically due to IP network congestion, while call failures between locations may be the result of network outages due to disconnected cables or improperly configured IP route tables.
Before assuming that call processing problems result from Cisco Unified Communications devices themselves, check the integrity of the backbone IP network. Keep the OSI model in mind as you perform these checks. Start from the bottom, at the physical layer, by checking that end-to-end cabling. Then verify the status of Layer 2 switches, looking for any port errors. Move from there to confirm that the Layer 3 routers are running and contain correct routing tables. Continue up the OSI stack to Layer 7, the application layer. To resolve problems occurring at the top levels of the stack, a protocol analyzer (or "sniffer") may be useful. You can use sniffer to examine the IP traffic passing between devices and also decode the packets. Sniffers are particularly useful for troubleshooting errors between devices that communicate using Media Gateway Control Protocol (MGCP) or Session Initiation Protocol (SIP).
Apply Tools to Determine the Problem's Root Cause
After you have eliminated the IP network as the source of the problem and you have isolated the specific Cisco Unified Communications components involved, you can start applying the many diagnostic tools provided by Cisco components.
Table 4 lists the diagnostic tools and supporting troubleshooting documentation available for most components in an IP telephony network. Note that this summary table is provided for reference only. The procedures in Troubleshooting Daily Operations specify when to use each tool and provide links to the troubleshooting instructions in each component's documentation where appropriate.
Table 4 IP Telephony Component Troubleshooting Tools and Documentation
Category | Component | Diagnostic Tools Available | Information Available In... |
Call Control | Cisco Unified Communications Manager | Serviceability System tools: •Alarms •Real-Time Monitoring Tool window Trace log files •Communications Manager trace log •SDL trace log (under TAC direction) | Troubleshooting Guide for Cisco Unified Communications Manager Cisco Unified Communications Manager Real-Time Monitoring Tool Administration Guide Cisco Unified Serviceability Administration Guide Cisco Unified Communications Manager CDR Analysis and Reporting Administration Guide for Cisco Unified Communications Manager Disaster Recovery System Administration Guide Troubleshooting TechNotes |
Cisco Unified Communications Manager Business Edition | Serviceability System tools: •Alarms •Real-Time Monitoring Tool window Trace log files: •Communications Manager trace log •SDL trace log (under TAC direction) | Troubleshooting Guide for Cisco Unified Communications Manager Cisco Unified Communications Manager Real-Time Monitoring Tool for Cisco Unified Communications Manager Business Edition Cisco Unified Serviceability Administration Guide for Cisco Unified Communications Manager Business Edition Cisco Unified Communications Manager CDR Analysis and Reporting Administration Guide for Cisco Unified Communications Manager Business Edition Disaster Recovery System Administration Guide |
Cisco Unified Communications Manager Express | IOS command line tools (such as Show commands and Debug trace utilities) | Troubleshooting Guides Troubleshooting TechNotes |
Cisco Unified Survivable Remote Site Telephony | IOS command line tools (such as Show commands and Debug trace utilities) | Cisco Unified SRST System Administrator Guide, "Monitoring and Maintaining Cisco Unified SRST" chapter |
Cisco Unified Communications 500 Series for Small Business | IOS command line tools (such as Show commands and Debug trace utilities) SNMP alarms/events | User Guide for the Catalyst Express 520 Switches, "Troubleshooting the Switch" chapter Cisco Unity Express GUI Administrator Guide, "Troubleshooting Cisco Unity Express" chapter Cisco Unity Express Voice-Mail and Auto-Attendant CLI Administrator Guide, "Troubleshooting" chapter |
Contact Center | Cisco Customer Response Solutions (Cisco Unified Contact Center Express) | Log files Alarms | Cisco Customer Response Solutions Servicing and Troubleshooting Guide, "Part II Troubleshooting" Troubleshooting TechNotes |
Application | Cisco Emergency Responder | E-mail alerts sent to administrator ERL Debug tool Cisco ER Admin Utility tool Call history logs SYSLOG collector tool that generates trace and debug files Windows Event Viewer | Cisco Emergency Responder Administration Guide, "Troubleshooting Cisco Emergency Responder" chapter Troubleshooting Guides |
Cisco Unified Application Environment | AppServer log files | Administration Guide for the Cisco Unified Application Environment, "Maintaining the Cisco Unified Application Environment" chapter |
Cisco Unified PhoneProxy | System log files: •Shell.log •Update.log •Phoneproxy.log | Cisco Unified PhoneProxy Administration Guide, "Troubleshooting" chapter |
Cisco Unified Presence | Configuration Troubleshooter Trace log files Alarms | Cisco Unified Presence Administration Guide, "Configuration Troubleshooter" section Cisco Unified Serviceability Administration Guide for Cisco Unified Presence, "Troubleshooting Trace Setting Configuration" section System Error Messages for Cisco Unified Presence Cisco IP Phone Messenger User Guide for Cisco Unified Presence, "Troubleshooting" section Disaster Recovery System Administration Guide for Cisco Unified Presence |
Conferencing | Cisco Unified MeetingPlace | Log files: •Gateway SIM event log •Error log gwcptrace CLI command | Administrator's Guide for Cisco Unified MeetingPlace Audio Server, "Troubleshooting the Cisco Unified MeetingPlace Audio Server System" chapter for voice/audio issues Installation and Upgrade Guide for Cisco Unified MeetingPlace Audio Server, "Troubleshooting the Cisco Unified MeetingPlace Audio Server System Installation" chapter for audio server installation issues Configuration Guide for Cisco Unified MeetingPlace Audio Server, "Troubleshooting the Cisco Unified MeetingPlace System Configuration" chapter for T1/E1 port and general MeetingPlace issues Configuration Guide for Cisco Unified MeetingPlace Web Conferencing, "Troubleshooting Cisco Unified MeetingPlace Web Conferencing" chapter for Web conferencing issues Administrator's Guide for Cisco Unified MeetingPlace Video Integration, "Troubleshooting" chapter for videoconferencing problems Administration Guide for Cisco Unified MeetingPlace for Microsoft Outlook, "Troubleshooting" chapter for Microsoft Outlook integration issues Administration Guide for Cisco Unified MeetingPlace Directory Services, "Troubleshooting Cisco Unified MeetingPlace Directory Services" chapter for directory services issues Troubleshooting TechNotes |
Cisco Unified MeetingPlace Express | System logs Alarms | Configuration and Maintenance Guide for Cisco Unified MeetingPlace Express, "Troubleshooting Cisco Unified MeetingPlace Express" chapter User Guide for Cisco Unified MeetingPlace Express, "Troubleshooting and Getting Help" chapter |
Conferencing (video) | Cisco Unified Video- conferencing Video Gateway 3521, 3522, 3526, 3527, 3545 | BRI/PRI link LEDs on front and rear panels BRI/PRI link LEDs viewable remotely using Gateway interface Gateway statistics | Administrator Guide for Cisco Unified Videoconferencing 3527 PRI Gateway and 3522 BRI Gateway, "Troubleshooting the Cisco Unified Videoconferencing 3500 Gateway" chapter Administrator Guide for Cisco Unified Videoconferencing 3545 PRI Gateway and 3545 Serial Gateway, "Troubleshooting the Cisco Unified Videoconferencing 3545 Gateway" chapter |
Video MCU 3515, 3540, 3545 | LEDs Command line interface | Administrator Guide for Cisco Unified Videoconferencing 3515 MCU12 and MCU24, "Troubleshooting the MCU" chapter Administrator Guide for Cisco Unified Videoconferencing 3545 MCU, "Troubleshooting the MCU" chapter Troubleshooting Guide for Cisco Unified Videoconferencing 3500 MCU |
Voice Mail and Unified Messaging | Cisco Unity | Event log Cisco Unity Diagnostic Tool (UDT): •Macro trace logs •Micro trace logs Voice Connector trace logs Tools Depot utilities: •Integration Monitor •Call Viewer •Port Status Monitor Dialogic tools (for systems equipped with Dialogic voice cards only): •TSP trace logs •Universal Dialogic Diagnostics Utility Dr. Watson logs for underlying Windows 2000 server platform | Troubleshooting Guide for Cisco Unity Release 5.x (With Microsoft Exchange) Troubleshooting Guide for Cisco Unity Release 5.x (With IBM Lotus Domino) Troubleshooting TechNotes |
Cisco Unity Connection | Serviceability System tools: •Alarms •Real-Time Monitoring Tool window Cisco Unity Diagnostic Tool (UDT): •Macro trace logs •Micro trace logs CuVrt service verbose logging | Real-Time Monitoring Tool Administration Guide for Cisco Unity Connection Administration Guide for Cisco Unity Connection Serviceability Cisco Unified Serviceability Administration Guide for Cisco Unity Connection Disaster Recovery System Administration Guide for Cisco Unity Connection Troubleshooting TechNotes |
Cisco Unity Express | CLI commands for status checking and performance monitoring SNMP alarms/events | Cisco Unity Express GUI Administrator Guide, "Troubleshooting Cisco Unity Express" chapter Cisco Unity Express Voice-Mail and Auto-Attendant CLI Administrator Guide, "Troubleshooting" chapter Troubleshooting TechNotes |
Endpoints and Clients | Cisco Unified IP phones | Network configuration, status and phone model information on Settings menu | End-User Guides Cisco Unified IP Phone Administration Guides for Cisco Unified Communications Manager, "Troubleshooting and Maintenance" chapters Error Message Decoder Output Interpreter Troubleshooting TechNotes |
Cisco IP Communicator | Quality Report Tool (QRT) Error Reporting Tool | Cisco IP Communicator Administration Guide, "Troubleshooting Cisco IP Communicator" chapter User Guide for Cisco IP Communicator, "Troubleshooting Cisco IP Communicator" chapter Troubleshooting TechNotes |
Cisco Unified Personal Communicator | Cisco Unified Problem Reporting Tool (Windows version only) | Troubleshooting Guide for Cisco Unified Personal Communicator User Guide for Cisco Unified Personal Communicator for Windows, "Troubleshooting" chapter for Windows version User Guide for Cisco Unified Personal Communicator for Macintosh, "Troubleshooting" chapter for Macintosh version |
Cisco Unified Video Advantage | Diagnostics Tool AutoUpdate Status Viewer CAST Viewer CDP Viewer Trace Tool Error Reporting Tool | Installation and Troubleshooting Guide for Cisco Unified Video Advantage, "Troubleshooting Cisco Unified Video Advantage" chapter Cisco Unified Video Advantage User Guide, "Troubleshooting Cisco Unified Video Advantage" chapter Troubleshooting TechNotes |
Network Management | Cisco Unified Operations Manager | Alarms and events appearing in Dashboard displays Phone status tests Synthetic test Node-to-node tests | User Guide for Cisco Unified Operations Manager, "Administering Operations Manager" chapter |
Cisco Unified Service Monitor | | User Guide for Cisco Unified Service Monitor, "Administering the System and Managing Data" chapter |
Communications Infrastructure | VG224 Analog Voice Gateway | IOS command line tools | VG224 Analog Phone Gateway Software Configuration Guide, "Using the ROM Monitor" chapter Troubleshooting Guides Output Interpreter Troubleshooting TechNotes |
Cisco Catalyst 3550 Access Switch | IOS command line tools (such as Show commands and Debug trace utilities) | Catalyst 3550 Multilayer Switch Software Configuration Guide, "Troubleshooting" chapter Error Message Decoder Output Interpreter Troubleshooting Tech Notes |
Cisco Catalyst 3560 Access Switch | IOS command line tools (such as Show commands and Debug trace utilities) | Catalyst 3560 Switch Software Configuration Guide, "Troubleshooting" chapter Catalyst 3560 Switch System Message Guide, "Catalyst 3560 Switch Debug Commands" chapter Error Message Decoder Output Interpreter Troubleshooting Tech Notes |
Cisco Catalyst 3750 Access Switch | IOS command line tools (such as Show commands and Debug trace utilities) | Catalyst 3750 Switch Software Configuration Guide, "Troubleshooting" chapter Catalyst 3750 Switch System Message Guide, "Catalyst 3750 Switch Debug Commands" chapter Error Message Decoder Output Interpreter Troubleshooting Tech Notes |
Cisco Catalyst 4506 Access Switch | IOS command line tools (such as Show and Debug commands) | Catalyst 4500 Series Installation Guide, "Troubleshooting the Installation" chapter Catalyst 4500 Series Switch Cisco IOS System Message Guide Error Message Decoder Output Interpreter Troubleshooting TechNotes |
Communications Infrastructure (continued) | Cisco Catalyst 6506, 6509 including Firewall Services Module (FWSM) and Communications Media Module (CMM) | IOS command line tools (such as Show commands and Debug trace utilities) | Catalyst 6500 Series Switch Installation Guide, "Troubleshooting" chapter Catalyst 6500 Series Error and System Message Guides Catalyst 6500 Series Switch and Cisco 7600 Series Router Firewall Services Module Command Reference for FWSM logging configuration and system log messages Error Message Decoder Output Interpreter Troubleshooting TechNotes |
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