文档介绍：Gathering Symptoms Stage of the General Troubleshooting Process3The Isolate the Problem Stage of the General Troubleshooting Process4The Correct the Problem Stage of the General Troubleshooting Process5OSIOSITCP/IPTCP/IPApplicationApplicationPresentationPresentationSessionSessionApplicationApplicationData LinkData paring the OSI Model with the TCP/IP Model6PhysicalPhysicalData LinkData work Devices Mapped to a Logical Layered ModelFirewallFirewallXXStandard SwitchStandard SwitchXXXXMultilayer SwitchMultilayer SwitchXXXXHubHubEnd-SystemEnd-SystemXXXXXXRouterRouterXXXXXXXXXX******XXXXXXXX7Resolving Problems at the Physical and Data Link Layers8Isolating the Problem? 2002, Cisco Systems, Inc. All rights Symptoms of Physical Layer work is functional, but is operating either consistently or intermittently less than the baseline work is functional, but is operating either consistently or intermittently less than the baseline levelFraming errorsFraming errorsLEDs are off, flashing, or in a state other than the expected state during normal operationLEDs are off, flashing, or in a state other than the expected state during normal operationIncreased number of interface errorsIncreased number of interface errorsExcessive utilizationExcessive utilizationManagement system alarmsManagement system mon Symptoms of Data Link Layer ProblemsThe link is functional, but is operating either consistently or intermittently less than the baseline levelThe link is functional, but is operating either consistently or intermittently less than the baseline levelFraming errorsFraming errorsEncapsulation errorsEncapsulation errorsAddress resolution errorsAddress resolution errorsExcessive CRC errors and frame check sequence errors Excessive CRC errors and frame check sequence errors Large quantities of broadcast traffic Large quantities of broadcast traffic A MAC address is cycling between portsA MAC address is cycling between ports