Spanning Tree | Cabletron Systems 2.2 specification

Bridging

Spanning Tree

The Bridge Spanning Tree window allows you to display and modify the deviceÕs bridge port information and protocol parameters relating to the Spanning Tree Algorithm.

In a network design with multiple bridges placed in parallel (i.e, attached to the same LAN), data loops must be prevented. The Spanning Tree Algorithm (STA) is the method that bridges use to communicate with each other to ensure that only a single data route exists between any two end stations.

On a LAN interconnected by multiple bridges, Spanning Tree selects a controlling Root Bridge and Port for the entire bridged LAN, and a Designated Bridge and Port for each individual LAN segment. A Designated Port/Bridge for a LAN segment forwards frames from that LAN towards the Root Bridge, or from the Root Bridge onto the LAN. All other bridge ports attached to that LAN are conÞgured to Þlter (block) frames.

When data passes from one end station to another across a bridged LAN, it is forwarded through the Designated Bridge/Port for each LAN segment towards the Root Bridge, which in turn forwards frames towards Designated Bridges/Ports on its opposite side.

During the Root Bridge Selection process, all bridges on the network communicate STA information via Bridge Protocol Data Units (BPDUs). With BPDUs, all network bridges collectively determine the current network topology and communicate with each other to ensure that the topology information is kept current.

To access the Bridge Spanning Tree window from the Bridge Status window:

1.Click on Bridge to display the Bridge menu.

2.Click on Spanning Tree. The Bridge Spanning Tree window, Figure 2-10, will appear.

To access the Bridge Spanning Tree window from the Chassis View window:

1.Click on the Board Index of the device of interest; the Board menu will appear.

2.Click on Spanning Tree. The Bridge Spanning Tree window, Figure 2-10, will appear.

2-34	Spanning Tree

Image 52

Cabletron Systems 2.2 manual Spanning Tree

Contents

Bridge/Router Interface Brim User’s Guide Page Virus Disclaimer Restricted Rights Notice Contents Contents Chapter Fddi Applications Chapter WAN ApplicationsChapter ATM Conﬁguration Index Contents Introduction Using the Brim User’s Guide BRIM-E100 Related Manuals Brim Management Applications Using the Mouse Software Conventions Left Mouse Button Right Mouse Button Common Device Window Fields Device NameIP Address Location Using Window Buttons Accessing On-line Documentation Using On-line HelpGetting Help Getting Help from the Cabletron Systems Global Call Center Hours a day, 365 days a year Introduction Getting Help Bridging Basics About Transparent Bridging About Source Route Bridging Bridging About Source Route-Transparent Bridges About Source Route-Translational Bridges Viewing and Managing Bridging Interfaces Bridging Bridge Status Window Bridge Status Window Up Time Accessing Bridge Status Window Options Bridge State on InterfaceInterface Type Bridge Address Bridging Bridging Bridging Bridging Enabling and Disabling Bridging Enabling and Disabling All Installed InterfacesEnabling and Disabling Individual Interfaces Bridge Statistics Performance Graphs Bridging Errors Red Frames Forwarded GreenFiltered Magenta Xmitted Blue Bridge Detail Breakdown Errors Frames ForwardedFiltered Xmitted Forwarded to Interface StatisticsForwarded from Address DescriptionType Error UnicastNon-Unicast Discarded Receive Errors Csmacd Statistics Transmission Errors Collision Errors PPP Link Statistics Errors Statistics Dot5 Errors Line Errors Burst Errors Internal Errors Congestion ErrorsToken Errors Soft Errors Source Route Statistics Received Frames Transmitted Frames Discards Spanning Tree Bridge Level Bridge Priority Root Bridge Root CostRoot Port Protocol Bridge Port Level Path Cost Designated CostDesignated Root Designated Bridge Changing Bridge Priority Conﬁguring Spanning TreeChanging the Spanning Tree Algorithm Protocol Type Changing Hello Time Changing Forwarding Delay TimeChanging Max Age Time Changing Port Priority Filtering DatabaseChanging Path Cost Bridging 11. The Filtering Database Window List NumberCapacity Aging Time Port Filtering Conﬁguring the Filtering DatabaseAltering the Aging Time Changing the Type of Entry Changing the Receive PortChanging the Port Filtering Action Adding or Deleting Individual Entries Special Filter Databases Clearing All Permanent, Static, or Dynamic Entries Ethernet and Token Ring Special Filter Database Windows Special Filter Database Window EnableFile Destination Address Source AddressData Type Data Offset Deﬁning and Editing Filters in the Special Database Changing the Receive Ports Setting the Port Filtering ActionChanging the Port Filtering Action Saving a Set of Filters to a File Enabling and Disabling a FilterClearing the Port Filtering Action Interface Conﬁguration Transparent Bridge MethodsSource Routing Setting the Bridge Method NetBIOSProtocol Transmission Methods Source Route Transparent Source Route Conﬁguration 16. Source Route ConÞguration Window Source Routing Information Source Route Conﬁguration Subnet Mask Local Segment Target SegmentHop Count Limit Spanning Tree Expl Spanning Tree Mode Bridge Number Using the Find Source Address Feature Making and Setting Changes Using the Port Source Addresses Window Setting the Aging Time Using the Token Ring Bridge and Port Conﬁguration Windows Bridging Virtual Ring Number Ring Number Port Mode Novell TranslationRing Speed Bridge Mode/Explorer Type Source Route/STE Duplex Modes Interface Duplex Modes WindowFull Duplex Setting the Duplex Mode Ethernet Port Conﬁguration Standard Mode Fast Ethernet Port Conﬁguration Bridging Current Operational Mode Desired Operational ModePort Type Link State Setting the Operational Mode for the FE-100TX Sonet Port Conﬁguration Setting the Operational Mode for the FE-100FXSONET/SDH Conﬁguration Sonet SONET/SDH Statistics Bridging 26. The SONET/SDH Statistics Window Errors Statistics Bridging Conﬁguring SmartTrunking 27. The SmartTrunk ConÞguration and Status Window Port NameMode SmartTrunk State Bridging Conﬁguring Broadcast Suppression Token Ring Bridge Mode Setting Token Ring Bridge Mode Setting Bridge Translation Enabling and Disabling Auto and Dual Translate Modes 32. Bridge Translation Window Conﬁguring Token Ring Packet Translation Conﬁguring Novell Token Ring Packet Translation IBM Translation Table Index State Snap Translation Table Conﬁguring Snap Translation Using the Novell Translation Window Bridging Using the Physical View Windows for the Etwmim Ethernet Port Physical View Active Port Epim Type Token Ring Port Physical View 41. Token Ring Port Physical View Ring State FNB State Active Monitor Bridging 104 Using the Physical View Windows for the Etwmim Fddi Applications Accessing the Fddi Menu Conﬁguration Window MAC State SMT Version Req. Requested Target Token Rotation TimeNeg. Negotiated Concentrator M Ports Connection Policy Window Concentrator Non-M PortsNumber of MACs MAC Path Connection Policy Window 15 32,768 Ð a permanently set value for this bit Station List Window Address ModeNumber of Nodes Node Class Upstream Neighbor Transmit Frames Fddi Performance WindowReceive Frames Frame Errors Setting the Time IntervalRing Ops Fddi Applications Fddi Performance Window Accessing the WAN Status Windows WAN Applications Current Active Viewing WAN Interface StatusCurrent Primary Conﬁguring the Synchronous Connection Desired Primary Inspeed OutspeedClock Source State Change Conﬁguring T-1 Ports WAN Port NameLine Type Line Coding Loopback Mode Signal ModeCircuit ID Xmt Clock Source Using the T1 FracTable Conﬁguration Window Interface LineCoding Max Bandwidth ChannelsConﬁguring the Fractional Table Restoring a Fractional Table Changing the Interface Line Coding Displaying the WAN Logical View Compression Changing WAN Logical Settings CRC Length Synchronous Admin/Status Viewing the WAN Port Admin/StatusOperational Status T1 Admin/Status Admin StatusOper and Admin WAN Interfaces Enabling and Disabling WAN T1 Interfaces Displaying Synchronous Port StatisticsFrame Check Total Errors Xmit UnderRunsReceive OverRuns Interrupted Frames WAN Applications Displaying Synchronous Port Statistics Accessing the ATM Connections Window ATM Conﬁguration Settings Connection Data Conﬁguring Connections VPI Adding a New Connection Deleting a Connection ATM Conﬁguration Conﬁguring Connections Index Index-2 Index-3 Index-4 Index-5 Index Index-6