3Com 2000 TR manual Source Routing

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5-4CHAPTER 5: CONFIGURING THE TR-IN-FE MODULE

Ports with a lower value have a higher priority and will be blocked only after ports with a higher value and a lower priority have been blocked.

Path Cost—Path cost determines the amount of overhead required to forward packets to the root through this port.

The higher the path cost, the less likely Spanning Tree will use a port for forwarding. The lower the cost, the more likely Spanning Tree will use a port for forwarding.

NOTE: It is always recommended that, in the case of a loop formed with a low speed port, the high-speed ports do not block. The switch automatically provides this function with default settings (port speed is part of the spanning tree calculations). Be aware of this, if the spanning tree values are modified.

Fast Fwd—Frames are forwarded as soon as the destination address is received and verified.

Source Routing

Source Routing is a method of allowing a ring station (node) on a Token Ring network to communicate with another ring station on a different ring intercon- nected by bridges. The “source” ring station, which is the node initiating the communication, is responsible for dynamically determining and then maintaining information about the “route” to the destination ring station. A route is simply the path a packet takes through a source route bridged network from the source ring station to the destination ring station.

In the case of TR-in-FE, a virtual LAN ID must be assigned to the FE cloud. This allows Source Routing to proceed as though the FE media supported TR natively. The entire FE transparently forwarded cloud appears as a single “ring” and hence a single hop to attached TR endstations. This also allows FE servers to participate in source routing.

Attached Lan Id—A unique number that identi- fies the segment to which the port connects. This value can be set between 0 and FFF (0-4095). A value of FFFF (65535) indicates that no segment number has been assigned to this port.

Max Route-Desc—This value describes the number of routing descriptions allowed in All Route Explorer (ARE) or Spanning Tree Explorer (STE) frames. This is also referred to as “hop count” limit since it limits the number of rings a packet can traverse.

STE Mode—This value determines how this port responds when presented with Spanning Tree Explorer (STE) packets. Set the field accordingly by pressing the [Space Bar].

Disabled—Indicates that the port will not accept or propagate STE packets, and any pack- ets received will be discarded.

Forced—Indicates that the port will always accept and propagate STE packets.

Auto-Span—Indicates that the port will accept and propagate STE packets when its Spanning Tree state is forwarding.

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Contents For SuperStack II Switch 2000 TR For units of the Department of Defense For civilian agenciesAbout this Guide 3COM Corporation Limited Warranty About this Guide IntroductionTerminology Finding Information in this Guide ConventionsAbout the SuperStack II Switch 2000 TR TR-in-FE Module OverviewTR-in-FE Benefits Summary of TR-in-FE Module Features HardwareSoftware 4CHAPTER 1 Overview What is Token Ring-in-Fast Ethernet TR-in-FE? TR-IN-FE ConceptsTR-in-FE Compared to Traditional Methods 3Com Token Ring-in-Fast Ethernet SystemToken Ring-in-Fast Ethernet Module How TR-in-FE Works How TR-in-FE WorksPower IIRedundant SuperStack Tunneling RequirementsToken Ring Frames 4Token Ring-in-Fast Ethernet Frame What is a Vlan Virtual LANs VlansAdvantages of Vlan Port-Based Distribution8CHAPTER 2 TR-IN-FE Concepts Installing and Setting UP the Module Following Safety InformationPre-installation Procedure Installation Post-Installation Checks LED SummaryChecking the Power Supply Checking that the TR-in-FE Module is Installed Correctly Checking the Physical ConnectionsJumper Settings 2TR-in-FE Module Jumper SettingsAccessing Management Features VT100 ConsoleChoice Field Entry FieldButton List BoxesKey Board Shortcuts Correcting Text EntriesDefault Users Default Name Password Access LevelConsole Menu Map 1VT100 Console Menu Map with I/O Module Detail Switch 2000 TR banner LCD ConsoleUser Name Default Access Level Password Logging OnLogging Off Automatic Logout8CHAPTER 4 Accessing Management Features Configuring the TR-IN-FE Module TR-in-FE Module Configuration MapSetting Up a Module 2I/O Module Screen ConfigBridge Parameters Spanning TreeSource Routing Setting Up a Vlan TR Vlan Info Setup ScreenTR Vlan Setup Screen Scroll the Vlan list using the Up and Down keys Monitoring the TR-IN-FE Module TR-in-FE Module Statistics MapStatistics Overview 2TR Port Statistics ScreenPort Statistics Traffic 3Sample TR Port Statistics Traffic ScreenClearing Screen Counters Jam CountsImportant Safety Information ’information de Sécurité ImportanteWichtige Sicherheitsinformationen Screen Access Rights Screen Access level required2APPENDIX B Screen Access Rights TR-IN-FE Module Technical Specifications Environmental SpecificationsTR-in-FE Cable Specification Does the Cable Provide Sufficient Bandwidth? ExampleCore mm Cladding mm Numerical Aperture TR-in-FE Cable Specification 4APPENDIX C TR-IN-FE Module Technical Specifications Online Technical Services 3Com Bulletin Board ServiceTechnical Support World Wide Web Site3ComFacts Automated Fax Service Support from Your Network Supplier3ComForum on CompuServe Country Telephone NumberSupport from 3Com Returning Products for RepairCountry Telephone Number Fax Number 4APPENDIX D Technical Support Numbers Page 3Com Corporation Limited Warranty HardwareGoverning LAW