Intel IXM5414E Troubleshooting STP

Intel® Blade Server Ethernet Switch Module IXM5414E 269

Troubleshooting STP

This section describes how to troubleshoot the STP.

Spanning Tree Protocol Failure

A failure in the Spanning Tree Algorithm generally results in a bridging loop. This is caused by a

port that should be in the discarding state but is instead forwarding packets.

In this example, B has been elected as the designated bridge and port 2 on bridge C is in the

discarding state. The election of B as the designated bridge is determined by the exchange of BPDUs

between bridges B and C. Bridge B had a better spanning tree priority vector than bridge C. Bridge

B continues sending BPDUs that advertise its superiority over the other bridges on this LAN. If

bridge C fails to receive these BPDUs for l onger than the Max. Age time (default of 20 seco nds), it

could start to change its port 2 from the discarding state to the forwarding state.

/ NOTE

To remain in the discarding state, a port must continue to receive BPDUs that advertise

superior paths.

There are several circumstances in which the algorithm can fail, mostly related to the loss of a large

number of BPDUs. These situations will cause a port in the discarding state to change to the

forwarding state.

Full/half duplex mismatch

A mismatch in the duplex state of two ports is a very common configuration error for a point-to-

point link. If one port is configured as full duplex and the other port is left in auto-negotiation mode,

the second port will end up in half-duplex because ports explicitly configured as half- or full-duplex

do not negotiate.

A

Root

B C

Blocked

Port1

Port1

Port1

Port1

Port1

Port1

Port2

Port2

Port2

Port2

Port2

Port2

BPDUs

Designated

Contents

Main Page Contents 1 Introducing the Intel Blade Server Ethernet Switch Module IXM5414E. . . . . . . 1 4 Switch Management and Operating Concepts . . . . . . . . . . . . . . . . . . . . . . . . . . .19 Page Safety Page Page Page Page Page 1 Introducing the Intel Blade Server Ethernet Switch Module IXM5414E Related publications Notices and statements used in this book Major components of the IXM5414E switch module Specifications and features Page Page Page Page 2 Installing and Removing the Intel Blade Server Ethernet Switch Module IXM5414E Ethernet interface requirements Installation guidelines System reliability considerations Handling static-sensitive devices Installing the IXM5414E switch module Page Page Removing the IXM5414E switch module Page Page 3 Information Panel LEDs and External Ports Information panel LEDs Page 4 Switch Management and Operating Concepts Intel Blade Server Ethernet Switch Module IXM5414E overview Chassis configuration and operation Switch module management and control IP addresses and SNMP community names Traps Management Information Bases (MIB) Port mirroring Simple Network Management Protocol (SNMP) Authentication Switching concepts Packet forwarding Spanning Tree Protocol (STP) Virtual Local Area Networks (VLAN) Notes about VLANs on the IXM5414E switch module IEEE 802.1Q VLANs IEEE 802.1Q VLAN packet forwarding IEEE 802.1Q VLAN tags Port VLAN ID Tagging and untagging Egress rules IEEE 802.1Q VLAN configuration Static MAC filtering Generic Attribute Registration Protocol (GARP) GARP VLAN Registration Protocol (GVRP) GARP Multicast Registration Protocol (GMRP) Internet Group Management Protocol (IGMP) snooping (LAG) Static LAGs Distribution method Dynamic Host Configuration Protocol (DHCP) Security IEEE 802.1X Local authentication RADIUS authentication Secure Shell (SSH) Secure Socket Layer (SSL) Quality of Service (QoS) Bandwidth provisioning Access Control Lists (ACL) Page 5 Web-Based Network Management Introduction Remotely managing the switch module Getting started Page Page System ARP cache Inventory information Page Configuration System description Network connectivity Page Teln et User accounts Page Login configuration Login session Login summary User login Page Forwarding database Search Page Logs Message log Event log Port Page Page Summary Page Mirroring SNMP Community configuration Trap receiver configuration Trap receiver summary Supported Management Information Bases (MIB) Statistics Switch detailed Page Page Switch summary Port detailed Page Page Page Page Page Page System utilities Save all applied changes System reset Page Page Page Upload file from switch Ping Trap manag er Trap flags Trap log Switching VLAN Page Page Page Page Reset configuration Filters MAC filter configuration MAC filter summary GARP Switch configuration Page Page IGMP snooping Configuration and status Interface configuration LAG Page MFDB MFDB table GMRP table IGMP snooping table Stats Spanning tree Switch configuration/status Common Spanning Tree (CST) configuration/status Page CST port configuration/status Page Statistics Class of service 802.1p priority mapping Security Port access control Page Page Port status Page Page Page Statistics Page Login Port access privileges Port access summary RADIUS Server configuration Page Page Page Accounting server configuration Accounting server statistics Clear statistics Secure HTTP Page Secure Shell QoS Access Control Lists Page Summary Rule configuration Page Page Bandwidth provisioning Bandwidth profile configuration Bandwidth profile summary Traffic class configuration Page Traffic class summary Interface allocation summary Logout Page 6 Updating the Ethernet Switch Software Determining the software version Obtaining the latest version Upgrading the switch software Upgrading the image using Telnet Upgrading the MCU code using Telnet Upgrading the image using web interface Upgrading the MCU code using web interface Resetting and restarting the switch module Page Page 7 Command Line Interface Management Command Line Interface (CLI) conventions Format Command name Parameters Valu es Comments Special characters Remotely managing the IXM5414E switch module Connecting to the IXM5414E switch module Changing configuration settings Managing user accounts Initial configuration IXM5414E switch module system commands System commands Address Resolution Protocol (ARP) cache Forwarding DB Inventory information Logs Port commands Page Page Simple Network Management Protocol (SNMP) Page Page System configuration Page Page Page System description Page Page Page Page Page Page Page System utilities Page Page Page Page Trap manager Switching configuration commands Generic Attribute Registration Protocol (GARP) commands config garp gmrp adminmode config garp gmrp interfacemode config garp gvrp adminmode config garp gvrp interfacemode config garp leavetimer show garp info show garp interface IGMP snooping commands config igmpsnooping adminmode config igmpsnooping groupmembershipinterval config igmpsnooping interfacemode config igmpsnooping maxresponse Link Aggregation (LAG) commands config lag addport config lag adminmode config lag create config lag deletelag config lag deleteport config lag linktrap config lag name MAC filter commands config macfilter adddest config macfilter create config macfilter deldest config macfilter remove Multicast Forwarding Database (MFDB) commands show mfdb gmrp show mfdb igmpsnooping show mfdb staticfiltering show mfdb stats show mfdb table Spanning tree commands Spanning tree bridge commands Spanning tree Common Spanning Tree (CST) commands Page Page Spanning tree port commands Spanning tree summary commands Virtual Local Area Network (VLAN) commands config vlan bcaststorm config vlan create config vlan delete config vlan makestatic config vlan name config vlan participation config vlan port acceptframe config vlan port priority config vlan port pvid config vlan port tagging show vlan detailed show vlan port show vlan summary Class of Service commands config classofservice 802.1pmapping show classofservice 802.1pmapping Security configuration commands Authentication commands config authentication login create config authentication login delete config authentication login set IEEE 802.1X commands clear dot1x port stats config dot1x adminmode config dot1x defaultlogin config dot1x login config dot1x port controlmode config dot1x port initialize config dot1x port quietperiod config dot1x port reauthenabled config dot1x port reauthenticate config dot1x port reauthperiod config dot1x port servertimeout config dot1x port transmitperiod config dot1x port users add config dot1x port users remove show dot1x port detailed show dot1x port stats show dot1x port summary show dot1x port users show dot1x summary Remote Authentication Dial-In User Service (RADIUS) commands RADIUS accounting commands RADIUS configuration / summary commands Page RADIUS server commands Page Secure Shell (SSH) commands Secure Socket Layer (SSL) commands Quality of Service (QoS) commands Access Control List (ACL) commands config acl create config acl delete config acl interface add config acl rule action config acl rule create config acl rule delete config acl rule match dstip config acl rule match dstl4port keyword config acl rule match every config acl rule match protocol keyword config acl rule match protocol number config acl rule match srcip config acl rule match srcl4port keyword config acl rule match srcl4port number show acl detailed show acl summary Bandwidth provisioning commands BW provisioning BW allocation commands BW provisioning traffic class commands Page Page Appendix A RJ-45 Pin Specifications Page Appendix B Cable Lengths Page Appendix C Run-time Switching Software Default Settings Table 9. Default settings for run-time switching software variables heading Varia ble Default value Command Quality of Service Security 232 Accounting Server Switching GVRP 234 Bridge CST Port x Mirroring 236 Trans fer Page Page Appendix D CLI Command Tree SWITCHING clear config 240 Page 242 Page 244 help logout ping reset save show Page 246 transfer Page Page Appendix E CLI Configuration Examples Bridging configuration example Page IEEE 802.1w configuration example VLAN configuration example Link aggregation configuration example IGMP snooping configuration example Access Control List configuration example Page Appendix F Troubleshooting the Spanning Tree Protocol Spanning Tree Protocol (STP) operation Creating a stable topology IEEE 802.1D STP port states IEEE 802.1w STP port states Setting user-changeable STP parameters Illustration of STP Intel Blade Server Ethernet Switch Module IXM5414E 263 / NOTE In this example, only the default STP values are used. A Blocked B C A Discarding state Learning state Forwarding state Page Disabled state Troubleshooting STP Spanning Tree Protocol Failure Full/half duplex mismatch B C Unidirectional link B C BC Packet corruption Resource errors Identifying a data loop Avoiding network problems Page AB CD Appendix G Getting Help and Technical Assistance Before you call Using the documentation Hardware and software service and support Page Page General Safety Electrical Safety Handling electrostatic discharge-sensitive devices Regulatory specifications and disclaimers Safety compliance Electromagnetic compatibility (EMC) Electromagnetic compatibility notice (USA) Electromagnetic compatibility notices (International)