Cisco Systems 2960 Monitor Switch Performance, Ping the End Device, Spanning Tree Loops

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Chapter 4 Troubleshooting

Diagnosing Problems

Use the show interfaces privileged EXEC command to verify the port or interface error-disabled, disabled, or shutdown status on both sides of the connection. If necessary, re-enable the port or the interface.

Ping the End Device

Verify the end device connection by first pinging it from the directly connected switch, and then work your way back port by port, interface by interface, trunk by trunk, until you find the source of the connectivity issue. Make sure that each switch can identify the end device MAC address in its Content-Addressable Memory (CAM) table.

Spanning Tree Loops

Spanning Tree Protocol (STP) loops can cause serious performance issues that might appear to be port or interface problems. In this situation, the switch bandwidth is used repeatedly by the same frames, crowding out legitimate traffic.

A unidirectional link can cause loops. This occurs when the traffic that the switch sends is received by its neighbor, but the switch does not receive the traffic that is sent from the neighbor. A broken fiber-optic cable, other cabling, or a port issue could cause this one-way communication.

You can enable the UniDirectional Link Detection (UDLD) protocol on the switch to help identify difficult-to-find unidirectional link problems. UDLD supports a normal mode of operation (the default) and an aggressive mode. In normal mode, UDLD detects unidirectional links because of incorrectly connected interfaces on fiber-optic connections. In aggressive mode, UDLD also detects unidirectional links caused by one-way traffic on fiber-optic and twisted-pair links and by incorrectly connected interfaces on fiber-optic links. For information about enabling UDLD on the switch, see the “Understanding UDLD” section in the software configuration guide.

Monitor Switch Performance

Review these sections when you troubleshoot switch performance problems:

Speed, Duplex, and Autonegotiation, page 4-4

Autonegotiation and NIC Cards, page 4-5

Cabling Distance, page 4-5

Speed, Duplex, and Autonegotiation

If the port statistics show a large number of alignment errors, frame check sequence (FCS), or late-collisions errors, a speed or duplex mismatch might be the problem.

A common issue with speed and duplex occurs when the duplex settings are mismatched between two switches, between a switch and a router, or between the switch and a workstation or server. This can happen when you manually set the speed and duplex or because of autonegotiation issues between the two devices.

These circumstances can result in a mismatch:

A manually set speed or duplex parameter is different from the manually set speed or duplex parameter on the connected port.

A port is set to autonegotiate, and the connected port is set to full duplex with no autonegotiation.

Catalyst 2960 Switch Hardware Installation Guide

4-4

OL-7075-05

 

 

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Contents Catalyst 2960 Switch Hardware Installation Guide Catalyst 2960 Switch Hardware Installation Guide N T E N T S Rack-Mounting2-8 Removing Screws from the Switch Console Port A-4 Starting the Terminal Emulation Software Audience PurposeConventions Related Documentation For information about related products, see these documentsPreface Preface Catalyst 2960 Switch Hardware Installation Guide Features Product Overview1000BASE-CWDM Catalyst 2960 Switch 24- and 48-Port Switches These sections describe the switch front panelsFront Panel Description Catalyst 2960-24-S, 2960-24TC-S, and 2960-48TC-S Switches 10/100 ports Dual-purpose ports10/100 ports 2 Dual-purpose ports Catalyst 2960-24TC-L Switch Front Panel Catalyst 2960G-24TC-L and Catalyst 2960G-48TC-L Switches 10/100 ports10/100 ports 2 10/100/1000 uplink ports These sections describe the Catalyst 2960 8-port switches Catalyst 2960 Switch 8-Port SwitchesCatalyst 2960PD-8TT-L Switch 10/100/1000 ports 2 Dual-purpose portsCatalyst 2960-8TC-L Catalyst 2960G-8TC -L Switches 10/100 PortsConsole port Dual-purpose port 10/100/1000 ports 10/100/1000 Ports PoE PortsSFP Module Slots Power Input Port Catalyst 2960PD-8TT-L Switch Dual-Purpose Port10/100/1000 Port 16 Connecting Through an External AC Power Adapter LEDsSpeed LED Mode buttonSystem LED Status LED Port LEDs Duplex LEDPort status Port status. This is the default mode Port LEDs and ModesPort speed Port operating speed 10, 100, or 1000 Mb/s Port Mode LED Color Meaning Meaning of Port LED Colors in Different Modes on the Switch Rear Panel Description Dual-Purpose Port LEDsPower Supplies Internal Power Supply ConnectorCisco RPS Connectors Cisco RPS 2300 Connector Console PortManagement Options Security SlotsSecurity slot Network Configurations OL-7075-05 Switch Installation 24- and 48-Port Switches Preparing for InstallationThis section covers these topics PWR-RPS2300, PWR675-AC-RPS-N1=. Statement Statement 371-Power Cable and AC Adapter Guidelines for Particulate Matter Installation Guidelines Verifying Package Contents Installing the Switch Verifying Switch OperationRemoving Screws from the Switch Rack-MountingAttaching Brackets to the Catalyst 2960 Switch Phillips flat-head screws137076 Mounting the Switch in a Rack Phillips machine screwsWall-Mounting Attaching the Cable GuideCable guide screw Phillips pan-head screws RPS connector RPS connector cover Attaching the Brackets to the Switch for Wall-MountingAttaching the RPS Connector Cover Phillips truss-head screwsMounting the Switch on a Wall User-supplied screwsInstalling and Removing SFP Modules Table- or Shelf-MountingInstalling SFP Modules into SFP Module Slots 13 SFP Module with a Bale-Clasp LatchRemoving SFP Modules from SFP Module Slots SFP moduleConnecting to the 10/100 and 10/100/1000 Ports Connecting to SFP Modules 16 Connecting to an Ethernet PortConnecting to Fiber-Optic SFP Modules 17 Connecting to a Fiber-Optic SFP Module PortConnecting to 1000BASE-T SFP Modules 18 Connecting to a 1000BASE-T SFP ModuleConnecting to a Dual-Purpose Port Where to Go NextStart an Snmp application such as the CiscoView application OL-7075-05 Switch Installation 8-Port Switches Statement 371-Power Cable and AC Adapter Installation Guidelines Equipment That You Supply Verifying Package Contents Verifying Switch Operation Desk- or Shelf-Mounting without Mounting ScrewsDesk- or Shelf-Mounting with Mounting Screws Installing the Mounting Screws on Top of a Desk or Shelf Mounting the Switch on Top of a Desk or Shelf Under the Desk- or Shelf-Mounting with Mounting ScrewsInstalling the Mounting Screws Under a Desk or Shelf Desk or shelf Screws Screw template AdhesiveMounting the Switch Under a Desk or Shelf Desk or shelf Slides on this way ScrewsWall-Mounting with Mounting Screws Wall Screw template ScrewsSwitch 3 Slides on this way Screw Installing the Switch On a WallMagnet Mounting MagnetAttaching Brackets to the Switch Phillips flat-head screwMounting the Switch in a 19-Inch Rack Wall-Mounting with Rack-Mount Brackets10 Mounting the Switch on a Wall Switch Installation 8-Port Switches Where to Go Next Diagnosing Problems This section includes these troubleshooting topicsVerify Switch Connections Verify Switch Post ResultsMonitor Switch LEDs Bad or Damaged CableEthernet and Fiber Cables Transceiver Module Port IssuesPort and Interface Settings Link StatusSpanning Tree Loops Monitor Switch PerformancePing the End Device Speed, Duplex, and AutonegotiationClearing the Switch IP Address and Configuration Autonegotiation and NIC CardsCabling Distance Locating the Switch Serial Number Cisco 11-character label200186 OL-7075-05 Connector Specifications Connecting to 10BASE-T- and 100BASE-TX-Compatible DevicesConnecting to 1000BASE-T Devices 3 4 5 6 7SFP Module Ports Dual-Purpose PortsCable and Adapter Specifications SFP Module Cable Specifications1310 1310 TX652 32,810 feet 10 km GLC-FE-100BX-D 1550 RX GLC-FE-100BX-U 50/125 500 Feet 2 km GLC-GE-100FX 62.5/125Two Twisted-Pair Cable Pinouts Four Twisted-Pair Cable Pinouts for 1000BASE-T PortsCrossover Cable and Adapter Pinouts Identifying a Crossover CableAdapter Pinouts TxD RxDRxD TxD Technical Specifications Power Requirements Physical Dimensions Power Requirements Accessing the CLI Accessing the CLI Through Express SetupConnecting to the Console Port Accessing the CLI Through the Console PortFigure C-1 Connecting a Switch to a PC Starting the Terminal Emulation SoftwareConnecting to a Power Source Entering the Initial Configuration InformationIP Settings Completing the Setup Program These choices appear Catalyst 2960 Switch Hardware Installation Guide OL-7075-05 OL-7075-05 AC power adapter for Catalyst 2960PD-8TT-L switch AC power Connecting toConnector Specifications Cable guide, attaching Cable lengthsConnection procedures Accessing by using Express Setup C-1Connecting to the console port Connectors and cables 10/100/1000 A-1 to A-2 ConsoleNo user-serviceable parts warning PoE Port modeSystem Troubleshooting with Lightning activity warning LEDs Color meaningsPort and interface troubleshooting Rack-mounting warning High-powered devicesOn Catalyst 2960-24PC-L and 24LT-L switches See also Mode button DescriptionConnectors Described Installation Attachment warning 1-19,2-2,2-7connecting to 2-7,3-6Safety warnings Shelf-mountingRead the wall-mounting instructions Trained and qualified personnel
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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.