Networking Knowledge Base

ResolutionComplete these steps to upload a configuration file from a switch to a TFTP server for storage:Log into the switch through the console port or a Telnet session.    Upload the switch configuration to the TFTP server with the copy config tftp...

ResolutionIf there is a duplex mismatch on an Inter-Switch Link (ISL) trunk into a Catalyst 5000 switch, the swBusCRCErrorDrop errors will be seen on all ports of the switch.The port with the mismatch will also see RxInnerCRCErrorDrop errors. If this...

Core issueThe Ternary Content Addressable Memory (TCAM) is used to forward lookups. TCAM is a specialized piece of memory designed for rapid table lookups by the Access Control List (ACL) engine on the switches. The ACL engine performs ACL lookups ba...

Core IssueThe console displays the %SYS-6-READ_BOOTFILE_FAIL error message during the boot.  After timing out, the router drops into boot mode.ResolutionTo resolve this issue, perform these steps:  Check the Network Processing Engine (NPE) version. T...

ResolutionTwo types of bridging configurations are possible on the Catalyst 2948G-L3 switch:All ports belonging to a single bridge groupGroups of ports belong to one or more bridge groupsIn the first case, a Layer 3 (L3) configuration is not required...

Core IssueThe following are the two types of parity errors:Soft parity errors - These occur when an energy level within the chip (a one or a zero, for example) changes. When referenced by the CPU, these errors cause the system to crash if the error i...

Core issueThe %MLS_STAT-SP-4-IP_LEN_ERR: MAC/IP length inconsistencies error message indicates the receipt of packets whose IP length does not match the MAC length. The Supervisor Engine drops these packets. These packet drops do not cause any negati...

Core issueThe user needs to understand Catalyst OS (CatOS) show port command output on Catalyst switches, including alignment, Frame Check Sequence (FCS), transmit and receive errors, runts, giants and various collisions counters.ResolutionMany perfo...

Core issueWhenever a forwarding switch port detects a topology change, it goes into the blocking state to reconfigure the tables regarding the spanning tree topology change. These are among the reasons for topology changes:The addition of a new switc...

ResolutionRefer to System Software Conversion from CatOS to Cisco IOS for Catalyst 6500/6000 Switches for complete instructions on how to convert a Catalyst 6000 series switch from hybrid mode to integrated Cisco IOS  Software.The document also discu...

Core IssueThe Versatile Interface Processor (VIP) crashes due to hardware issues. These are the error messages in Cisco IOS  Software Releases later than 11.3(7):%VIP2-1-MSG: slot4 System reloaded by a fatal hardware error %VIP2-1-MSG: slot4 caller=...

ResolutionThere are no restrictions regarding the number of trunks in a Catalyst 6500 Switch. It all depends on the amount of traffic the VLANs carry. As a best practice, to avoid congestion due to broadcast or multicast, it is suggested that you ena...

Enhanced Interior Gateway Routing Protocol Enhanced Interior Gateway Routing Protocol (EIGRP) is a Cisco proprietary enhanced distance vector routing protocol, relying on the Diffused Update Algorithm (DUAL) to calculate the shortest path to a destin...

ResolutionThere are two main network management implementation techniques for Multiprotocol Label Switching (MPLS) VPN networks.For more information, refer to the Management VPN Technique and Out-of-Band Technique sections of The ISC Management Netwo...

Core IssueThe Catalyst 6500 and 6000 series switches use the Supervisor Engine for Layer 2 (L2) switching and the Multilayer Switch Feature Card (MSFC), which is a daughter card, on the Supervisor Engine for Layer 3 (L3) routing functionality. The sw...