Networking Knowledge Base

Core issueThe %PLATFORM_UCAST-3-ADJ: error message occurs in very rare conditions when a continuous MAC address change is reported for an adjacency. This message appears when the adjacency module for unicast routing encounters an error. Typically, th...

ResolutionAn Open Shortest Path First (OSPF) neighbor status that does not reach the Full state does not necessarily represent a problem.OSPF neighbors can be in any one of the following states:DownAttemptInit2-WayExstartExchangeLoadingFull For more ...

Core issueThis is an example of the error message:RMON-5-FALLINGTRAP: Falling trap is generated because the value of [chars] has fallen below the falling-threshold value [dec]This means a falling trap has been generated. The value of the specified MI...

Core IssueHot Standby Router Protocol (HSRP) provides redundancy for IP networks, ensuring that user traffic immediately and transparently recovers from first hop router failures. HSRP allows multiple routers on a single LAN to share a virtual IP and...

Core issueIn rare circumstances, in the C4948G switches that run Cisco IOS  Software Release 12.2(25)EWA2 or later, which includes Cisco IOS Software Release 12.2(25)SG, one or more ports can get stuck without any receiving (Rx) or transmitting (Tx) ...

ResolutionA trunk is a point-to-point link that sends and receives traffic between switches, or between switches and routers. Trunks carry the traffic of multiple VLANs and can extend VLANs across an entire network. 100Base-T and Gigabit Ethernet tru...

Core issueThe error message looks similar to this:%C6KERRDETECT-2-LPBKFAIL: The in-band loopback test between switch processor and route processor failed, count:[dec] This indicates that the system detected an unrecoverable in-band loopback test erro...

Core issueConfiguration BPDUs are sent every 2 seconds from the Root bridge to the other bridges in the network, by default. The above message indicates that a configuration BPDU was not received by a non-designated port on a switch for 20 seconds (a...

Core IssueThe most common reason for this problem is forgetting to configure the Network Address Translation (NAT) with the overload keyword.ResolutionIf you only have one routable address for your internal network to translate to, configure NAT to o...

Core issueIn-Service Software Upgrade (ISSU) is the first, comprehensive, transparent software upgrade capability in the industry for the IP/Multiprotocol Label Switching edge router. Full image ISSU allows you to upgrade the complete Cisco IOS  soft...

Core IssueIntermediate System-to-Intermediate System (IS-IS) recognizes networks as either point-to-point or broadcast. On point-to-point networks, point-to-point IS-IS Hellos (IIHs) are exchanged, while on broadcast networks Level 1 or Level 2 LAN I...

Core issueThe telnet session can hang when you issue the show cam dynamic command in order to display the Dynamic Content-Addressable Memory (CAM) table entries. After you log back in and clear the CAM table with the clear cam dynamic command, you ca...

Core issueWhen the VLAN Trunking Protocol (VTP) mode is changed from VTP client mode to vtp transparent mode, the service providers loose Open Shortest Path First (OSPF) capabilities, but the IP connectivity is unaffected. The OSPF announcements beco...

ResolutionMultilayer Switch Feature Card 1 (MSFC1) does not contain Error-Correcting Code (ECC) memory protection. Therefore, the MSFC crashes if a parity error is detected. These error messages may occur in the following locations:On the console:***...

Core issueThe %GIGASTACK-1-NO_LOOP_DETECT message indicates the link neighbor of link [dec] of  GigaStack GBIC in [chars] did not respond to the loop detection request. If loop  topology is deployed, make sure all switches in the stack are running th...