Networking Knowledge Base

Core IssueThe issue is caused by defective hardware or a mis-seated network module.ResolutionIf the router is in boot loop mode and displays this error message, perform these steps:Power down the router.Remove all network modules and power the router...

ResolutionTo resolve this issue, perform these options: Connect the console cable from the console port of the router to the COM port of the PC.Open the Hyperterminal on the PC, select the correct COM port, and use these settings:Speed: 9600 bpsDatab...

Core Issueistance Vector Multicast Routing Protocol (DVMRP) is modeled after Routing Information Protocol version 1 (RIPv1) with few differences and uses a flood and prune mechanism similar to Protocol Independent Multicast (PIM) dense mode. DVMRP bu...

Core IssueThe Xmodem software download procedure can be used when there are no TFTP servers or network connections and a direct PC connection (or modem connection) to the router's console is the only viable option.  Because this procedure relies on t...

ResolutionThese modules are either feature cards attached to the Supervisor Engine, or separate modules installed in the chassis:  Multilayer Switch Feature Card I (MSFC)Multilayer Switch Feature Card II (MSFC2)Multilayer Switch Module (MSM)Route Swi...

Core IssueThis message indicates that the router crashed because of a signal trap exception.ResolutionTo resolve this issue, perform these steps:Capture the command output from the show version and show stacks commands.      To determine if a known i...

Core IssueThese issues may prevent the Border Gateway Protocol (BGP) neighbors from being established:The neighbor IP address or Autonomous System (AS) number is incorrect. In a non-directly connected neighbor, no routes to the neighbor IP address ex...

Core IssueOnly one WIC-1ENET card is supported in all versions of Cisco IOS  Software Release 12.1, and 12.2 versions earlier than 12.2(2)XJ, 12.2(2)XK and 12.2(8)T. To work, the WIC-1ENET card must be installed in slot0. An error message is displaye...

Core IssueBorder Gateway Protocol (BGP) is an interdomain routing protocol used to exchange network reachability information with configured peers known as BGP neighbors. Interior BGP (IBGP) has certain behavior and follows certain rules to ensure th...

ResolutionAn EtherChannel is the aggregation of multiple physical links to provide redundancy and increased bandwidth between the devices. EtherChannel bundles can have up to eight physical ports of the same speed and media type, depending on the swi...

Core IssueFor an Open Shortest Path First Protocol (OSPF) process to begin, the router must have an interface with a valid IP address in the state of up, line protocol up.ResolutionVerify that you have an interface with a valid IP address in the stat...

ResolutionWhenever you install a new card, module or Cisco IOS  Software image, verify that the router has enough memory and that the hardware and software are compatible with the features you are using. To check for hardware and software compatibili...

Core IssueThe issue is caused by a Versatile Interface Processor (VIP) crash.  The processor is reset and is not used until the next Online Insertion and Removal (OIR) event or microcode download. It is retested at that time.ResolutionTo determine th...

Core IssueThe Versatile Interface Processor (VIP) card model VIP2-10 and VIP2-15, and the Fast Ethernet Interface Processor (FEIP) card models CX-FEIP2-2TX and CX-FEIP2-2FX require 16MB of memory when used with Cisco IOS  Software Release 12.0 and la...

Core issueThe Gigabit Ethernet interface of the Catalyst 2960 series switch fails in the PortPhiLoopback Packet Test of the power-on self-test (POST). This problem is observed in a Catalyst WS-C2960-48TT-L that runs Cisco IOS  Software Release 12.2(2...