Cabletron Systems 9A100 Troubleshooting Congestion, Diagnosing Congestion, Global Congestion

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Troubleshooting Congestion

Troubleshooting

5.4TROUBLESHOOTING CONGESTION

If the bandwidth of your SmartSwitch 9A100 begins to decrease, and if connections are being lost or packets are being dropped at a high rate, it’s possible that your switch is becoming congested. Congestion can occur on the port level, the global switch level, or both levels.

If you suspect that your SmartSwitch 9A100 switch is experiencing congestion, follow the steps outlined below to diagnose and resolve the cause of congestion.

5.4.1Diagnosing Congestion

1.Enter the show portstats command, and take the default of (all).

2.If cells are not being dropped on all ports, proceed to the “Port Congestion” section.

3.If cells are being dropped on all ports, the indication is global congestion. Proceed to the “Global Congestion” section.

5.4.2Global Congestion

1.Is the total cell drop rate equal to the Unknown VC cell drop rate?

If yes, the switch is improperly set up. Check the switch configuration.

If no, this indicates global congestion. Continue.

2.Set the porttrafficcongestion values to those recommended in the “QoS Queue Allocation Guidelines” section. Has the congestion subsided?

If yes, you are done.

If no, continue.

3.Have you changed the EPD threshold?

If yes, replace it to the default setting. If congestion subsides, you are done.

If no, continue.

4.Enter the show cacinfo command for each port. Is the allocated bandwidth small and is the traffic mostly UBR?

If no, go back to step 4 and check next port.

If yes, continue.

5.Enter the show porttrafficcongestion command. Is the UBR queue Max threshold large?

If no, go back to 4.

If yes, continue.

6.Reduce the UBR queue Max threshold by a small amount, then wait a few minutes.

7.Enter the show portstats command, and take the default of all. Is the number of cells dropped increasing for this port, and quickly decreasing for all other ports?

If yes, proceed to the “Port Congestion” section.

If no, continue.

5-4 SmartSwitch 9A100 User Guide

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Contents SmartSwitch 9A100 User Guide SmartSwitch 9A100 User Guide FCC Class a Notice Declaration of Conformity Addendum Safety Information Class 1 Laser Transceivers Fiber Optic Protective Caps Regulatory Compliance Summary Safety Revision History Table of Contents Specifications Acronyms Index Xii SmartSwitch 9A100 User Guide List of Figures List of Figures Xiv SmartSwitch 9A100 User Guide List of Tables List of Tables Xvi SmartSwitch 9A100 User Guide Introduction Introduction SmartSwitch 9A100 User Guide Switch Installation and Setup Unpacking the SwitchCheck Accessory Carton Contents Inspecting the Switch SmartSwitch 9A100-04 front panel1 DS3 and E3 I/O Module Configuration Installing the Switch Installing the SmartSwitch 9A100 Configuring the Switch SmartSwitch 9A100 console and network connections Using the Console Console CommandsSmartSwitch # show portconfig a1 Creating an Alias SmartSwitch # set consoletimeoutConsole Time-out TrafficAmbiguous Commands SwitchTrafficCongestion. For exampleConsole Help Smartswitch ATM AdministratorSmartSwitch # ? add laneclient ExteriorSmartSwitch ATM Administrator Installation Steps MB RAMStarting SmartSwitch ATM Administrator the First Time Accessing Online HelpUser Name Access Level Default Password SmartSwitch ATM Administrator SmartSwitch # add ipatmclient IP Over ATM and LaneCreating AN IP Over ATM Vlan Server Is local Server Connection Established Creating AN Emulated LAN ATM Addressing for IP over ATM3900000000000000000014418000005A01010100 Add Elan No Lane server address is specified see note belowIlmi ELANs Across Multiple Switches ATM Addressing for LAN EmulationSwitch Clients SmartSwitch# add laneclientElan1 Page Switch Administration Backing UP and Restoring Switch ConfigurationPath /backdir/config-1 ATM Routing SmartSwitch# restore switchSmartSwitch # show netprefix b2 Creating an Iisp RouteAtmAddress AtmrouteIisp route across Pnni domain UNI Routes Route Metrics SmartSwitch # show pnnimetrics IP Routing90.1.1.254 Route NET TableEvents and Alarms Event CategoriesViewing Events and Alarms SmartSwitch # set eventdisplayDeleting Events and Alarms SmartSwitch # set alarmdisplayPVC Connections Point-to-Point PVCs SmartSwitch # add trafficdescriptorSmartSwitch # show trafficdescriptor 100Point-to-Multipoint PVCs Md1 #add trafficdescriptorConnecting to Local Switch Client Through a PVC Local10.1.1.0 Non-zero VPIs VCC Mask Index VPI Bits VPI Values VCI Bits VCI ValuesUse show portconfig to see the change to port A1 SmartSwitch # set portconfig a1Traffic Management Traffic DescriptorsType Number Descriptor Characteristics Traffic Descriptor with CLP and best effortCall Admission Control Policy 80005000 Ubr SmartSwitch # set porttrafficcongestion Min for CBR queueQoS Queue Recommended Settings SmartSwitch # show switchtrafficcongestionEFCI, EPD, and RM Thresholds Accessing the Boot Load Prompt Upgrading and Changing SoftwareBoot Load Commands Command Action ParametersUpgrading Boot Load Software Boot PromFlash RAM =df b Upgrading Post Diagnostic Software =chpi=df p Upgrading Switch Operating Software =df sUsing the Update Firmware Command SmartSwitch # update firmware214.95.77.240 Saving Core Dumps 204.95.77.240 Tftpboot/bobr/coreSet CoreDump command BobrError IP e0103288 PFP e04be080 R0pfp e04be040 R1sp e04be0c0 Troubleshooting Troubleshooting IP Over ATMTroubleshooting LAN Emulation Troubleshooting Pnni Links Troubleshooting Congestion Diagnosing CongestionGlobal Congestion Port Congestion Troubleshooting Congestion Appendix a Specifications FunctionFigure A-1 SmartSwitch 9A100 front panel Specification Value ¢ %+2,%/˜96%,,%,329Table A-4 ATM port specifications Protocol StandardManagement Protocol Supported MIBs RJ-45 Pin RJ-45 Color DB-9 Pin DB-9 DescriptionTechnical Specifications Appendix B Agent Support MIB, SMI, MIB Files and Internet MIB HierarchyZeitNet Cabletron Proprietary MIBs MIB, SMI, MIB Files and Internet MIB HierarchyRelation Between Object Identifier and the Represented Value Supported protocols Supported SMI FormatsZeitnet Cabletron Proprietary MIB Groups Name Object Identifier FunctionSmartSwitch 9A100 MIB Support MIB ExceptionsManaging the SmartSwitch 9A100 Console Commands that Affect the Agent Update firmware Backup Restore RebootAppendix C Technical Support FAX ServiceElectronic Services Telephone AssistanceHardware Warranty Software WarrantyRepair Services Appendix D Acronyms Bootp DTE FCS Ilmi LES Netbeui PDU RMA SVC VBR/RT Acronyms SmartSwitch 9A100 User Guide Index NumericsElan Lane Snmp Lane Pnni Non-zero values