Moxa Technologies PT-7728 user manual STP/RSTP Concept, What is STP?

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PT-7728 User’s Manual

Featured Functions

The STP/RSTP Concept

Spanning Tree Protocol (STP) was designed to help reduce link failures in a network and provide protection from loops. Networks that have a complicated architecture are prone to broadcast storms caused by unintended loops in the network. The PT-7728’s STP feature is disabled by default. To be completely effective, you must enable RSTP/STP on every PT-7728 connected to your network.

Rapid Spanning Tree Protocol (RSTP) implements the Spanning Tree Algorithm and Protocol defined by IEEE Std 802.1w-2001. RSTP provides the following benefits:

yThe topology of a bridged network will be determined much more quickly compared to STP.

yRSTP is backward compatible with STP, making it relatively easy to deploy. For example:

¾It defaults to sending 802.1D style BPDUs if packets with this format are received.

¾STP (802.1D) and RSTP (802.1w) can operate on different ports of the same PT-7728. This feature is particularly helpful when PT-7728 ports connect to older equipment, such as legacy switches.

You get essentially the same functionality with RSTP and STP. To see how the two systems different, please refer to Differences between RSTP and STP later in this chapter.

NOTE	The STP protocol is part of the IEEE Std 802.1D, 1998 Edition bridge specification. The
	explanation given below uses bridge instead of switch.

What is STP?

STP (802.1D) is a bridge-based system that is used to implement parallel paths for network traffic. STP uses a loop-detection process to:

yLocate and then disable less efficient paths (i.e., paths that have a lower bandwidth)

yEnable one of the less efficient paths if the most efficient path fails

The figure below shows a network made up of three LANs separated by three bridges. Each segment uses at most two paths to communicate with the other segments. Since this configuration can give rise to loops, the network will overload if STP is not enabled.

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Contents First Edition, February Moxa Inc Moxa PowerTrans Switch PT-7728 User’s ManualDisclaimer Copyright NoticeTrademarks Table of Contents Appendix a MIB Groups Appendix B Specifications Introduction ‰ Overview ‰ Package Checklist ‰ Software FeaturesOverview Package ChecklistSoftware Features Getting Started Serial Console Configuration 115200, None, 8, 1, VT100 PT-7728 User’s Manual Getting Started Key Function Configuration by Telnet ConsolePT-7728 User’s Manual Getting Started PT-7728 User’s Manual Getting Started Configuration by Web Browser Disabling Telnet and Browser Access Featured Functions System Identification Configuring Basic SettingsAccount PasswordPassword Grant access to one host with a specific IP address Accessible IPGrant access to any host on a specific subnetwork Hosts That Need Access Input FormatPort EnableDescription NameFDX Flow Ctrl NetworkSpeed Switch IP Address Auto IP ConfigurationSwitch Subnet Mask Default GatewayDaylight Saving Time TimeCurrent Time Current DateSystem File Update-By Remote Tftp Tftp Server IP/Name Configuration Files Path and NameFirmware Files Path and Name Log Files Path and NameFactory Default System File Update-By Local Import/ExportPort Trunking Concept Using Port TrunkingTrunk Group Maximum of 4 trunk groups Configuring Port TrunkingTrunk Type Available Ports/Member PortsTrunk Table Configuring SnmpSetting Description Snmp Versions Snmp Read/Write SettingsV1, V2c Read Community V1, V2c Write/Read Community1st Trap Server IP/Name Setting Description Factory Default Setting Description Factory DefaultPrivate MIB information Using Communication RedundancyTurbo Ring Concept Initial setup for Turbo Ring or Turbo RingTurbo Ring with odd number switches Determining the Redundant Path for Turbo Ring Ring Coupling ConfigurationSwitch B Configuring Turbo Ring Configuring Turbo Ring and Turbo RingDual-Homing Configuration for Turbo Ring Master/Slave Now ActiveRedundancy Protocol Set as MasterCoupling Control Port Enable Ring CouplingCoupling Port Ring 1/2-Status Enable RingRing 1/2-1st Ring Port Status Ring 1/2-2nd Ring Port Status Coupling-ModePrimary/Backup Port Coupling ModeSTP/RSTP Concept What is STP?PT-7728 User’s Manual Featured Functions How STP Works STP ConfigurationSTP Requirements Port Speed Path Cost 802.1D Edition 802.1w-2001STP Example STP ReconfigurationDifferences between Rstp and STP Using STP on a Network with Multiple VLANs Root/Not Root Configuring STP/RSTPProtocol of Redundancy Bridge PriorityEnable STP per Port Forwarding DelayHello Time sec Max. Age secConfiguration Limits of RSTP/STP Using Traffic PrioritizationWhat is Traffic Prioritization? Traffic Prioritization ConceptIeee 802.1p Priority Level Ieee 802.1D Traffic Type How Traffic Prioritization WorksTraffic Queues Differentiated Services DiffServ Traffic MarkingTraffic Prioritization QoS Classification Configuring Traffic PrioritizationQueuing Mechanism Inspect TOSCoS Mapping Setting Description FactoryTOS/DiffServ Mapping Inspect COSVirtual LAN Vlan Concept Using Virtual LANWhat is a VLAN? Benefits of VLANs VLANs and the PowerTransManaging a Vlan Communication Between VLANsVLANs Tagged and Untagged Membership Sample Applications of VLANs using PT-7728PT-7728 User’s Manual Featured Functions Vlan Settings Configuring Virtual LANManagement Vlan ID Port TypeWhat is an IP Multicast? Using Multicast FilteringConcept of Multicast Filtering Vlan TableNetwork without multicast filtering Benefits of MulticastMulticast Filtering Igmp Internet Group Management Protocol Snooping Mode Multicast Filtering and Moxa PowerTrans SwitchQuery Mode Network with multicast filteringIgmp Multicast Filtering Configuring Igmp SnoopingGmrp Garp Multicast Registration Protocol Static Multicast MACIgmp Snooping Settings Add Static Multicast MAC Configuring Gmrp Using Bandwidth ManagementGmrp enable Gmrp TableIngress Configuring Bandwidth Management Broadcast Storm ProtectionTraffic Rate Limiting Settings Configuring Static Port Lock Using Port Access ControlStatic Port Lock IeeeDatabase Option Configuring IeeeRadius Server Server PortLocal User Database Setup 802.1X Re-AuthenticationLocal User Database Setup Using Auto WarningPort Access Control Table Event Type Configuring Email WarningMoxaPowerTransSwitch0001@SwitchLocation Email SetupPort Events Mail Server IP/NamePassword Setting Configuring Relay WarningAccount Name Email AddressEvent Setup Using Set Device IP Using Line-Swap-Fast-RecoveryConfiguring Line-Swap Fast Recovery Override relay alarm settingsSet up the connected devices Configuring Set Device IPMirror Port Using DiagnosisPing Using MonitorMonitor by Switch Monitor by Port Using the MAC Address TableMAC Using Event LogSyslog Server Using SyslogPT-7728 User’s Manual Featured Functions MIB II.2 Interfaces Group MIB II.1 System GroupMIB II.4 IP Group MIB II.5 Icmp GroupMIB II.17 dot1dBridge Group MIB II.10 Transmission GroupMIB II.11 Snmp Group Private Traps Public TrapsInterface Switch PropertiesTechnology Optical Fiber 100BaseFX PowerEnvironmental WarrantyMechanical