Chapter 4 Troubleshooting

Diagnosing Problems

•Verify that both devices have power.

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

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

PoE Connections

When a powered device is connected to PoE port, but no power is received, you should:

•Use the Mode button to show the PoE status for all ports. See Table 1-9and Table 1-10for a description of the LEDs and their meanings.

•Check the port status by using the show interfaces privileged EXEC command to check the port error-disabled, disabled, or shutdown status. Re-enable the port if necessary.

•Verify that the power supply installed in the switch meets the power requirements of your connected devices. See the “Power-Supply Modules” section on page 1-15for more information.

•Check the cable type. Many legacy powered devices, including older Cisco IP phones and access points that do not fully support IEEE 802.3af, might not support PoE when connected to the switch by a crossover cable. Replace the crossover cable with a straight-through cable.

Caution PoE faults are caused when noncompliant cabling or powered devices are connected to a PoE port. Only standard-compliant cabling can be used to connect Cisco pre-standard IP phones and wireless access points or IEEE 802.3af-compliant devices to PoE ports. (You must remove a cable or device that causes a PoE fault from the network.)

Transceiver Issues

Use only Cisco X2 transceiver modules and SFP modules on the switch. Each Cisco module has an internal serial EEPROM that is encoded with security information. This encoding provides a way for Cisco to identify and validate that the module meets the requirements for the switch. Check these items:

•Bad or wrong X2 transceiver, Cisco TwinGig Converter module, or SFP module. Exchange suspect module with known good module. Verify that the module is supported on this platform. (The switch release notes on Cisco.com list the X2 and SFP modules that the switch supports.)

•Use the show interfaces privileged EXEC command to check the port or module error-disabled, disabled, or shutdown status. Re-enable the port if needed.

•Make sure that all fiber connections are properly cleaned and securely connected.

•For CX4 module connections, make sure that cable routing does not violate the minimum allowed cable bend radius. See the module documentation for specific cabling requirements.

•For LX4 modules, a mode conditioning patch is recommended for MMF applications.

Port and Interface Settings

An obvious but sometimes overlooked cause of port connectivity failure is a disabled port. Verify that the port or interface is not disabled or powered down for some reason. If a port or interface is manually shut down on one side of the link or the other side, the link does not come up until you re-enable the

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Cisco Systems 3750-E, 3560-E manual PoE Connections, Transceiver Issues, Port and Interface Settings
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3750-E, 3560-E specifications

Cisco Systems RPS (Redundant Power System) 2300, along with the 3750-E and 3560-E series switches, represents a significant technological advancement in enterprise networking. These devices are designed to enhance network reliability, scalability, and efficiency, making them integral components in modern enterprise infrastructures.

The Cisco RPS 2300 is designed to provide redundant power to specified Cisco switches, ensuring continuous operation during power disruptions. This system can support up to six devices, enhancing power reliability and reducing downtime. The modularity of the RPS 2300 contributes to its flexibility, allowing enterprises to customize their power solutions to suit their networking needs. It features dual power input, which provides an additional layer of failover capability, ensuring that even in the event of a primary power failure, the backup power system can take over seamlessly.

On the other hand, the Cisco 3750-E series switches are enterprise-class devices that offer a rich feature set to support advanced network functions. These switches come with Cisco’s StackWise technology, enabling users to stack up to nine switches in a single logical unit. This increases port density and simplifies network management. The 3750-E also supports Power over Ethernet (PoE), allowing the delivery of power directly to devices like IP phones and access points through the networking cables. The switch is equipped with high-performance Layer 3 routing capabilities, providing enhanced IP routing options for enterprise networks.

The Cisco 3560-E series switches share many of the advanced features found in the 3750-E models but focus more on providing comprehensive Layer 2 and Layer 3 capabilities in a compact design. The 3560-E series supports Cisco’s advanced security features, such as dynamic VLAN assignment and security group access control lists (ACLs). Additionally, these switches support IPv6, preparing enterprise networks for future growth and addressing requirements.

Both the 3750-E and 3560-E are equipped with energy-efficient technologies, including intelligent power management and support for Energy Efficient Ethernet (EEE), helping organizations reduce their environmental footprint and operating costs. The integration of Cisco’s robust IOS software ensures that these devices are equipped with the latest features, ensuring strong performance, security, and scalability.

In summary, Cisco's RPS 2300, 3750-E, and 3560-E series exemplify the company's commitment to delivering cutting-edge networking solutions that meet the demands of modern enterprises, focusing on reliability, advanced features, and energy efficiency.
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