Networking Knowledge Base

ResolutionCreate a VLAN, and configure a Layer 3 (L3) VLAN interface. Assign an IP address for this interface, as shown: Switch(config)# vlan vlan_ID Switch(config)# interface vlan vlan_ID Switch(config-if)# ip address ip_address subnet_mask Configur...

Core issueSpanning Tree Protocol (STP) is a Layer 2 (L2) protocol that runs on bridges and switches. The specification for STP is IEEE 802.1D. The primary purpose of STP is to ensure loops are not created when redundant paths are present in the netwo...

Core IssueBorder Gateway Protocol (BGP) is an interdomain routing protocol used to exchange network reachability information.  Problems with BGP could stem from factors such as these:High volume of routing information, which requires a large amount o...

ResolutionInternet Explorer does not have passive FTP enabled by default. If you were attempting to access the FTP area using Internet Explorer, you can enable passive FTP.Perform these steps:Select Tools > Internet Options.Click the Advanced tab.Scr...

ResolutionYou may have a soft or hard parity error: Soft parity errors occur when an energy level within the chip changes, such as a one or a zero. When referenced by the CPU, the energy level within the chip causes the system to crash if the error i...

Core IssueThis message indicates that the neighbor did not acknowledge a reliable packet after at least 16 retransmissions. This could occur for these reasons: The link is a unidirectional link.There are incorrect IP addresses on the tunnel interface...

Core IssueAn enterprise may want to connect to the Internet through multiple Internet Service Providers (ISPs) for fault tolerance and load balancing.  At this point, the routing overhead these enterprises impose on the Internet routing system become...

Core issueSYS-3-SYS_LCPERR3: Module [dec]: Coil [dec] Port [dec] stuck  [dec] times ([dec] due to lcol; [dec] due to notx) is a system error message added to  the Catalyst OS (CatOS) code versions 7.2(2) and later. This message normally indicates tha...

Core issueThis is similar to how the full log message looks:%SYS-2-MALLOCFAIL: Memory allocation of 1028 bytes failed from 0x601617A4, pool Processor, alignment 0 -Process= "IP Input", ipl= 2, pid= 21These messages indicate that a process was unable ...

Core issueThe cat4000-cv CiscoView images are not bootable. Therefore, if the switch has only the cat4000-cv bin file on the Flash, the device does not boot.ResolutionTo resolve this issue, perform these steps:When performing a software upgrade on a ...

Core IssueIP packets can be filtered using Access Control Lists (ACLs) to control what traffic enters and leaves a network. ACLs can be configured and applied in inbound and outbound directions on an interface for packet filtering. Inbound ACLs check...

Core issueThis message indicates that the CPU is near the operating temperature threshold limit. [dec] is the CPU number.ResolutionMake sure there is adequate cooling in the chassis and that the chassis vents are clear. Also check if the fan tray is ...

Core issueError Message has been receieved.ResolutionTo identify an error message not currently listed in the LAN Switching knowledge base, please refer to the Error Message Decoder.Problem TypePort message receivedSyslog error message receivedError ...

Core issueThe Incorrect trunk type specified for port error message is received when the set trunk negotiate command is issued to configure the type of trunk encapsulation.When the set trunk negotiate command is issued and the module of the switch su...

Core IssueA router can continually display the log messages because the service config command is enabled on the router.These error messages usually occur after the router has performed a Cisco IOS  Software upgrade. In the latest version of Cisco IO...