Switch Connections, Bad or Damaged Cable

Chapter 3 Troubleshooting

Diagnosing Problems

Switch Connections

Bad or Damaged Cable

Always examine the cable for marginal damage or failure. A cable might be just good enough to connect at the physical layer, but it could corrupt packets as a result of subtle damage to the wiring or connectors. You can identify this situation because the port has many packet errors or the port constantly flaps (loses and regains link).

•Examine or exchange the copper or fiber-optic cable with a known, good cable.

•Look for broken or missing pins on cable connectors.

•Rule out any bad patch panel connections or media convertors between the source and the destination. If possible, bypass the patch panel, or eliminate faulty media convertors (fiber-optic-to-copper).

•Try the cable in another port or interface, if possible, to see if the problem follows the cable.

•Remove and inspect the stack cable and stack port for bent pins or damaged connectors. If the cable is bad, replace it with a known good cable.

Ethernet and Fiber-Optic Cables

Make sure that you have the correct cable for the connection

•For Ethernet, use Category 3 copper cable for 10 Mb/s UTP connections. Use either Category 5, Category 5e, or Category 6 UTP for 10/100 or 10/100/1000 Mb/s connections.

•For fiber-optic cables, verify that you have the correct cable for the distance and port type. Make sure that the connected device ports both match and use the same type encoding, optical frequency, and fiber type.

•For copper connections, determine if a crossover cable was used when a straight-through was required or the reverse. Enable auto-MDIX on the switch, or replace the cable. See Table 2-1for recommended Ethernet cables.

Link Status

Verify that both sides have link. A single broken wire or a shutdown port can cause one side to show link even though the other side does not have link.

A port LED that is on does not guarantee that the cable is fully functional. The cable might have encountered physical stress that causes it to function at a marginal level. If the port LED does not turn on:

•Connect the cable from the switch to a known good device.

•Make sure that both ends of the cable are connected to the correct ports.

•Verify that both devices have power.

•Verify that you are using the correct cable type. See Appendix B, “Connector and Cable Specifications” for information.

•Look for loose connections. Sometimes a cable appears to be seated, but is not. Disconnect the cable and then reconnect it.

Catalyst 2960-S Switch Hardware Installation Guide

3-2	OL-19732-04

2960S, WSC2960S24TSSRF, 2960S-24TS-S, 2960 specifications

Cisco Systems 2960 series switches are a prominent solution in the networking landscape, known for their reliability, scalability, and feature-rich offerings. Ideal for small to medium-sized enterprises, these switches provide a robust foundation for network infrastructure, ensuring optimal performance and connectivity.

One of the standout features of the Cisco 2960 series is its Layer 2 switching capabilities. The switches support multiple VLANs (Virtual Local Area Networks), allowing network administrators to segment traffic efficiently and enhance security protocols. This is crucial in modern networks where managing traffic and isolating sensitive information is a priority.

The Cisco 2960 series also incorporates advanced Quality of Service (QoS) features, enabling the prioritization of critical applications and services. This functionality ensures that time-sensitive data, such as voice and video traffic, maintains a high quality of service even in congested networks. With support for IEEE 802.1p and DSCP marking, administrators can fine-tune their network performance to meet specific organizational needs.

Power over Ethernet (PoE) is another significant characteristic of the Cisco 2960 series. This feature allows switches to deliver electrical power alongside data over Ethernet cables to devices such as IP phones, wireless access points, and surveillance cameras. With PoE, organizations can reduce clutter from power cables and increase deployment flexibility for various devices.

In terms of security, the Cisco 2960 series is equipped with a range of integrated security features. The switch supports port security, 802.1X authentication, and Access Control Lists (ACLs), providing robust defenses against unauthorized access and potential network vulnerabilities. These security measures are essential for protecting sensitive data and ensuring compliance with industry regulations.

Moreover, the Cisco 2960 series offers enhanced network management capabilities with Cisco's Intelligent Network Services. This includes support for Simple Network Management Protocol (SNMP), Cisco Prime, and Embedded Event Manager (EEM), allowing for efficient monitoring, troubleshooting, and policy enforcement across the network.

Additionally, the Cisco 2960 switches provide various models and configurations, catering to different networking needs. Options include models with varying port densities, uplink configurations, and stacking capabilities, making it easy for organizations to choose solutions that align perfectly with their requirements.

In summary, the Cisco 2960 series is a versatile and essential component of modern networking environments. Its advanced features, including Layer 2 support, QoS, PoE, robust security, and diverse management tools, make it an excellent choice for organizations looking to build a strong and secure network infrastructure.