Chapter 3 Troubleshooting

Diagnosing Problems

Check Switch LEDs

You must have physical access to the switch to do this. Look at the port LEDs for troubleshooting information about the switch. See the “LEDs” section on page 1-8for a description of the LED colors and their meanings.

Check Switch Connections

Review this section when troubleshooting switch connectivity problems.

Bad or Damaged Cable

Always check the cable for marginal damage or failure. A cable might be sufficient to connect at the physical layer but then cause packet corruption because of subtle damage to its wiring or connectors. You can identify this situation because the port will have many packet errors, or the port will constantly lose and regain link. In these situations:

•Check or change the copper or fiber-optic cable with a known, good cable.

•Look for broken or missing pins on cable connectors.

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

•Try using the cable in another port or interface to see if the problem also exists there.

Ethernet and Fiber Cables

Make sure that you have the correct cable type for the connection:

•For Ethernet, use Category 3 copper cable for 10 Mb/s unshielded twisted pair (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 connectors, verify that you have the correct cable for the distance and port type. Make sure that the ports on the connected device match and that they use the same type of encoding, optical frequency, and fiber type. For more information about cabling, see Appendix A, “Connector and Cable Specifications.”

•For copper connections, determine if a crossover cable was used when a straight-through cable was required, or the reverse. Enable auto-MDIX on the switch, or replace the cable.

Link Status

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

A link LED 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 link light for the port does not come 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.

Cisco ME 3400 Ethernet Access Switch Hardware Installation Guide

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Cisco Systems ME 3400 manual Check Switch LEDs, Check Switch Connections, Bad or Damaged Cable, Ethernet and Fiber Cables
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ME 3400 specifications

Cisco Systems ME 3400 Series is a robust family of Ethernet access switches designed specifically for service provider environments. These switches are engineered to deliver excellent performance, reliability, and flexibility, making them ideal for deploying Layer 2 and Layer 3 services to residential and business customers.

One of the prominent features of the ME 3400 series is its support for advanced Ethernet technologies. It provides extensive support for both traditional and modern Ethernet services, including Carrier Ethernet. With features such as Ethernet Operations, Administration, and Maintenance (EOAM), the ME 3400 aids in managing network performance and troubleshooting issues effectively. This capability ensures that service providers can deliver high-quality services and maintain optimal network health.

The ME 3400 series includes various models that support a range of port configurations, enabling scalability and adaptability to different network needs. This includes support for both Fast Ethernet and Gigabit Ethernet interfaces. The switches can accommodate multiple speed configurations, making them versatile for diverse deployment scenarios, from small businesses to large enterprise networks.

Another key characteristic of the ME 3400 is its integrated support for resilient Ethernet technologies, such as EtherChannel, Spanning Tree Protocol (STP), and Rapid Spanning Tree Protocol (RSTP). These technologies enhance redundancy and improve network reliability, crucial for service providers who require minimal downtime and high service availability.

Security is a top priority for service providers, and the ME 3400 series addresses this with extensive security features. It supports VLANs for traffic segmentation, access control lists (ACLs) for traffic filtering, and DHCP snooping to prevent unauthorized access to the network. These security measures ensure that both consumer and enterprise traffic remains isolated and secure.

Additionally, the ME 3400 series supports IPv4 and IPv6 routing, offering flexibility for service providers to cater to a broad customer base. The ability to manage both protocols ensures that networks can evolve seamlessly as internet traffic transitions to IPv6.

With energy efficiency increasingly becoming a concern, Cisco has integrated power-saving features into the ME 3400 series. These switches support Energy Efficient Ethernet (EEE) technology, which reduces power consumption during periods of low traffic, helping service providers to reduce operational costs.

In summary, the Cisco ME 3400 series is a versatile platform rich in features that streamline service delivery while ensuring high performance, security, and energy efficiency. It is an ideal choice for service providers looking to enhance their Ethernet services and meet evolving customer demands.
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