Moxa Technologies EDS-726 user manual STP Example, Using STP on a Network with Multiple VLANs

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EDS-726 Series User’s Manual

Featured Functions

STP Example

The LAN shown below has three segments, with adjacent segments connected using two possible links. The various STP factors, such as Cost, Root Port, Designated Bridge Port, and Blocked Port are shown in the figure.

LAN Segment 1

Port 1 (Designated Bridge Port)

Bridge A

Port 2

(Root Bridge)

Port 1

(Root Port)

Cost =100

Bridge B

Port 2 (Designated Bridge Port)

Port 1

(Root Port)

Cost =100

Bridge X

Port 2 (Blocked Port)

LAN Segment 2

Port 1

(Root Port)

Cost =100

Bridge C

Port 2 (Designated Bridge Port)

Port 1

(Root Port)

Cost =200

Bridge Y

Port 2 (Blocked Port)

LAN Segment 3

yBridge A has been selected as the Root Bridge, since it was determined to have the lowest Bridge Identifier on the network.

ySince Bridge A is the Root Bridge, it is also the Designated Bridge for LAN segment 1. Port 1 on Bridge A is selected as the Designated Bridge Port for LAN Segment 1.

yPorts 1 of Bridges B, C, X, and Y are all Root Ports sine they are nearest to the Root Bridge, and therefore have the most efficient path.

yBridges B and X offer the same Root Path Cost for LAN segment 2. However, Bridge B was selected as the Designated Bridge for that segment since it has a lower Bridge Identifier. Port 2 on Bridge B is selected as the Designated Bridge Port for LAN Segment 2.

yBridge C is the Designated Bridge for LAN segment 3, because it has the lowest Root Path Cost for LAN Segment 3:

¾The route through Bridges C and B costs 200 (C to B=100, B to A=100)

¾The route through Bridges Y and B costs 300 (Y to B=200, B to A=100)

yThe Designated Bridge Port for LAN Segment 3 is Port 2 on Bridge C.

Using STP on a Network with Multiple VLANs

IEEE Std 802.1D, 1998 Edition, does not take into account VLANs when calculating STP information—the calculations only depend on the physical connections. Consequently, some network configurations will result in VLANs being subdivided into a number of isolated sections by the STP system. You must ensure that every VLAN configuration on your network takes into account the expected STP topology and alternative topologies that may result from link failures.

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Contents First Edition, July Moxa EtherDevice Switch EDS-726 Series User’s ManualTrademarks Copyright NoticeDisclaimer Table of Contents Chapter EDS Configurator GUI Introduction Industrial Networking Capability Package ChecklistFeatures OverviewRecommended Software and Accessories Useful Utility and Remote ConfigurationGetting Started Connection Caution RS-232 Console Configuration 115200, None, 8, 1, VT100EDS-726 Series User’s Manual Key Function Configuration by Telnet Console Configuration by Web Browser EDS-726 Series User’s Manual Disabling Telnet and Browser Access Featured Functions System Identification Configuring Basic SettingsSwitch Description PasswordSwitch Name Switch LocationAccount PasswordAllowable Hosts Input format Accessible IPAny host on a specific subnetwork can access the EDS-726 Any host can access the EDS-726Name EnablePort DescriptionPort Type NetworkPort Transmission Speed FDX Flow ControlDefault Gateway Auto IP ConfigurationSwitch IP Address Switch Subnet MaskSystem Up Time TimeCurrent Time Current DateSystem File Update-By Remote Tftp System File Update-By Local Import/Export System File Update-By CF Card Using Port TrunkingFactory Default Port Trunking Concept Configuring Port Trunking Member Ports/Available Ports Setting DescriptionTrunk Group Maximum of 4 trunk groups Trunk TypeSnmp Configuring SnmpV1, V2c Write/Read Community Snmp Read/Write SettingsSnmp Versions V1, V2c Read CommunityTrap Server IP/Name Trap SettingsGigabit Ethernet Redundant Ring Capability 300 ms Using Communication RedundancySwitch Object ID Private MIB informationTurbo Ring Concept Initial SetupWhen the number of EDS-726 units in the Turbo Ring is even Ring Coupling Configuring Turbo Ring STP/RSTP Concept What is STP? STP Requirements How STP WorksPort Speed Path Cost 802.1D Edition 802.1w-2001 STP Calculation STP ConfigurationSTP Reconfiguration Differences between Rstp and STPSTP Example Using STP on a Network with Multiple VLANsConfiguring STP/RSTP Bridge priority Forwarding DelayRoot/Not Root Protocol of RedundancyPort Cost Configuration Limits of RSTP/STPEnable STP per Port Port PriorityHow Traffic Prioritization Works Using Traffic PrioritizationWhat is Traffic Prioritization? Traffic Prioritization ConceptIeee 802.1p Priority Level Ieee 802.1D Traffic Type Differentiated Services DiffServ Traffic MarkingTraffic Prioritization QoS Classification Configuring Traffic PrioritizationTraffic Queues Inspect COS Default Port PriorityQueuing Mechanism Inspect TOSCoS Mapping Setting Description FactoryTOS/DiffServ Mapping What is a VLAN? Using Virtual LANVirtual LAN Vlan Concept Communication Between VLANs VLANs and Moxa EtherDevice SwitchBenefits of VLANs Managing a VlanHUB Sample Applications of VLANs using Moxa EDS-726Vlan Port Settings Configuring 802.1Q VlanPort Forbidden Vlan List Management Vlan IDPort Pvid Port Fixed Vlan List TaggedBenefits of Multicast Using Multicast FilteringWhat is an IP Multicast? Concept of Multicast FilteringNetwork without multicast filtering Multicast FilteringIgmp Multicast Filtering Multicast Filtering and Moxa EtherDevice SwitchIgmp Internet Group Management Protocol Snooping Mode Query ModeEnabling Multicast Filtering Configuring Igmp SnoopingIgmp Snooping Settings Static Multicast MACIgmp Table Igmp SnoopingStatic Multicast Router Port QuerierJoin Port Add Static Multicast MACAdd New Static Multicast Address to the List NonePort Mode Setting Description Factory Default Configuring GmrpPort Setting Description Factory Default Gmrp enable Setting Description Factory DefaultBroadcast Storm Protection Using Bandwidth ManagementConfiguring Bandwidth Management Gmrp TableStatic Port Lock Using Port Access ControlTraffic Rate Limiting Settings IeeeMessage Exchange 802.1X Configuring IeeeShared Key Database OptionRadius Server Server PortLocal User Database Setup 802.1X Re-Authentication802.1X Re-Authentication Static Port Lock Local User Database Setup802.1X Table Configuring Email Warning Using Auto WarningEmail Alarm Events Settings Port Event MoxaEtherDeviceSwitch0001@SwitchLocationEvent Types System EventEmail Settings Activate your settings Configuring Relay WarningRelay Alarm Events Settings Configuring Relay Event TypesOverride relay alarm settings Relay Alarm ListEnable Line-Swap-Fast-Recovery Using Line-Swap-Fast-RecoveryUsing Set Device IP Configuring Line-Swap Fast RecoverySet up the connected devices Configuring Set Device IPBi-directional Using DiagnosisMirror Port Output data streamMonitor by Switch Using MonitorPing Monitor by Port Using the MAC Address TableALL Using Event LogEDS Configurator GUI Broadcast Search Starting EDS ConfiguratorSearch by IP address Upgrade FirmwareModify IP Address Export Configuration Import Configuration Unlock Server EDS-726 Series User’s Manual MIB II.5 Icmp Group MIB II.1 System GroupMIB II.2 Interfaces Group MIB II.4 IP GroupMIB II.11 Snmp Group MIB II.10 Transmission GroupMIB II.17 dot1dBridge Group Private Traps Public TrapsInterface Modular Managed Switch System, EDS-72610GGigabit Ethernet Interface Module, IM series PowerMechanical Optical Fiber Fast Ethernet Interface Module, IM seriesInterface Regulatory Approvals EnvironmentalService Information Following services are provided Moxa Internet ServicesSerial Number Problem Report FormProduct Return Procedure