Networking Knowledge Base

Core issueIf the standby supervisor engine module is not coming online (indicated by the status of other or faulty in the output of the show module command, or indicated by amber status LED), it may be due to one of the common reasons indicated in th...

Core issueThe DTP-5-DOMAINMISMATCH: Unable to perform trunk negotiation on port [chars] because of VTP domain mismatch error message indicates that the two ports in the trunk negotiation belong to different VTP domains. Trunking can be configured onl...

Core issueA software upgrade on the active Supervisor fails even after you copy the code from  the bootflash on the secondary (up and running new code) directly to the bootflash on the  primary. Cisco IOS  on both Supervisor Engines must be the same ...

Core issueMAC address reduction is disabled, not permitting extended-range VLANs to be created.ResolutionExtended (VLAN numbers up to 4096) was first supported on the Catalyst 6000 series in CatOS 6.1(1), and on the Catalyst 4000 series in CatOS 7.2(...

Core issueIn Catalyst OS (CatOS), a default gateway must be defined on the Supervisor Engine.  This default gateway is usually the IP address of an active interface on the router.  The router may be internal, such as the MultiLayer Switch Feature Car...

Core IssueIn order for Border Gateway Protocol (BGP) to advertise a classless network generated by issuing the network BGP configuration command, a valid route must exist in the routing table.ResolutionA valid route is an exact route matching the net...

Core IssueBecause the Cisco 3600 series routers have two Flash SIMM slots and there is no requirement that the Flash SIMMs be the same size, it is possible to add a second Flash SIMM on a router with only one SIMM installed and copy an image to it us...

Core IssueNetwork Address Translation (NAT) with support for the Microsoft NetMeeting application requires either a J or an O image, enterprise feature set, or Cisco IOS  Software Firewall feature set respectively.ResolutionYou need to be running a C...

Core IssueIn this case, the file system on the device from which the CPU tries to load the Cisco IOS  Software image is corrupted.ResolutionDepending on the router model, choose from these resolution options:Boot from another Flash device.Boot from t...

Core IssueThe TLB (Load/Fetch) Exception error message is often the result of a bus error. This is an example of the error message: *** System received a Bus Error exception ***Access address = 0x3c210040signal= 0xa, code= 0x1c, context= 0x60e632f0PC...

Core issueA hardware boot ROM upgrade might be required to upgrade the Catalyst OS (CatOS) on a Supervisor Engine I or IA.ResolutionThe Supervisor Engine I or IA requires a minimum boot ROM of 5.2(1) for software release 5.4(1) and later 5.x(x) relea...

Core issueThis error occurs when the Spanning Tree Protocol (STP) debug is on. These messages  are cosmetic and occur when you have either bridge groups or VLANs. This is caused by the specific debug spanning tree exception and can be ignored.Resolut...

Core IssueRefer to the Soft Versus Hard Parity Errors section of Processor Memory Parity Errors (PMPEs).ResolutionMultiple parity errors are a sign of a hardware failure.For the 7200 series router, replace the Network Processor Engine (NPE) and the m...

Core Issue ResolutionMultiple Hot Standby Routing Protocol (MHSRP) support is based on hardware limitations instead of software limitations. The interface must be able to associate an Ethernet interface with multiple unicast MAC addresses. Any router...

Core IssueThe configuration register is set to ignore startup configuration.ResolutionIssue the config-register command from global configuration mode, and set the configuration register to 0x2102.For more information, refer to Why Does My Router Los...