Networking Knowledge Base

Core IssueThe Cisco 2600 and 3600 series routers do not support the squeeze command in Cisco IOS Software versions earlier than 12.2(1). Cisco IOS Software versions 12.2(1) and later do support the command. However, for the command to work, the Flash...

Core issueIf the switch supervisor engine LED is red or the status is faulty, the cause can be a hardware problem. Another possibility is that the supervisor engine is installed in the wrong slot.If the supervisor engine is installed in an incorrect ...

Core issueThis message means that an excessive number of link up or down events have occurred on this interface. [chars] represents the interface, and [dec] represents the number of times the link goes up and down. This error can result if the port i...

ResolutionThis message means that the Enhanced Address Recognition Logic (EARL) was not able to set the Content Addressable Memory (CAM) aging time for the VLAN to 15 seconds, which is fast aging.The reason the EARL cannot set the VLAN to fast aging ...

Core IssueWhat do Cisco routers do for these SNMP MIB variables: ifInOctets, ifInUcastPkts, ifInNUcastPkts, ifInDiscards, ifInErrors, ifInUnknownProtos, ifOutOctets, ifOutUcastPkts, ifOutNUcastPkts, ifOutDiscards, ifOutErrors, and ifOutQLen.Resolutio...

ResolutionIf runts and Cyclic Redundancy Check (CRC) errors are incrementing in the show interface command output, or Frame Check Sequence (FCS) errors and runts are incrementing in the show port command output, check the port speed and duplex settin...

Core IssueA Border Gateway Protocol (BGP) Autonomous System (AS) is identified by a number in the range 1 to 65535. AS numbers in the range 1 to 64511 are assigned by InterNIC. These are reserved and globally unique AS numbers. AS numbers in the rang...

Core issueA duplex mismatch is reported if the settings on two sides of a link are different.ResolutionIssue the show interfaces command for Cisco IOS  Software and the show port command for Catalyst OS (CatOS) commands, and check the duplex settings...

Core issueThis error message indicates that the chassis temperature is above the threshold. If the temperature goes above a critical threshold, another message is logged. The system also shuts down to prevent damage to the hardware. ResolutionTo reso...

Core issueUnlike the other Cisco 7900 series IP phones, the Cisco 7935 IP conference phone does not have a 10/100 port to connect to a PC. Therefore, the concept of voice or auxiliary VLAN is not directly applicable. This can cause problems.Refer to ...

Core IssueMultiprotocol Label Switching - Traffic Engineering (MPLS-TE) provides an integrated approach to traffic engineering by combining the traffic engineering capabilities of ATM with the flexibility and Class of Service (CoS) differentiation of...

Core issueA Catalyst switch generates LINK-4-ERROR error messages after configuration changes.  This message means that excessive errors have occurred on the interface specified by [char] and occurs due to duplex mismatch between both ends of the lin...

Core issueThe system fan assembly should operate whenever the system power is on. You should be able to hear the fan assembly to determine if it is operating. The fan LED on the supervisor should be green.ResolutionTo resolve this issue, perform thes...

Core IssueUnder rare conditions, such as when a large amount of information needs to be exchanged, the Inter-Process Communications (IPC) buffer cache can become depleted. The Cisco IOS  Software reports this condition using these log messages: Oct 7...

Core IssueThe configuration register is probably set to a value that enables the break key in normal operation.ResolutionIssue the config-register command to change the configuration register to a value that disables the break key. The most common va...