For more information about STP and RSTP, see Using | 3Com 3 instruction

16CHAPTER 1: SWITCH FEATURES OVERVIEW

Spanning Tree Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP) Protocol and Rapid are bridge-based systems that makes your network more resilient to

Spanning Tree link failure and also provides protection from network loops — one of Protocol the major causes of broadcast storms.

STP allows you to implement alternative paths for network traffic in the event of path failure and uses a loop-detection process to:

■Discover the efficiency of each path.

■Enable the most efficient path.

■Disable the less efficient paths.

■Enable one of the less efficient paths if the most efficient path fails.

RSTP is an enhanced version of the STP feature and is enabled by default.

RSTP can restore a network connection quicker than the STP feature.

STP conforms to the IEEE 802.1D-1998 standard, and RSTP conforms to the IEEE 802.1w standard.

For more information about STP and RSTP, see Chapter 4 “Using

Resilience Features”.

Switch Database The Switch Database is an integral part of the Switch and is used by the Switch to determine if a packet should be forwarded, and which port should transmit the packet if it is to be forwarded.

For more information about the Switch Database, see Chapter 5 “Using the Switch Database”.

Traffic Prioritization Traffic prioritization allows your network traffic to be prioritized to ensure that high priority data, such as time-sensitive and system-critical data is transferred smoothly and with minimal delay over a network.

Traffic prioritization ensures that high priority data is forwarded through the Switch without being delayed by lower priority data. Traffic prioritization uses the two traffic queues that are present in the hardware of the Switch to ensure that high priority traffic is forwarded on a different queue from lower priority traffic. High priority traffic is given preference over low priority traffic to ensure that the most critical traffic gets the highest level of service.

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3Com 3 manual For more information about STP and RSTP, see Using, Resilience Features

Contents

SuperStack 3Com Corporation 5400 Bayfront Plaza Santa Clara, California Contents Using Multicast Filtering Status Monitoring and Statistics IP Addressing About this Guide Conventions List conventions that are used throughout this guide Related DocumentationComments Pddtechpubscomments@3com.com Product Registration Switch Features Page What is Switch FeaturesManagement Software? Switch Features Overview Ports operating at 1000 Mbps only support full duplex mode For more information about multicast filtering, see UsingDuplex Flow Control For more information about STP and RSTP, see Using Resilience Features For more information about Quality of Service, see Using Quality of ServiceEvent Notification For more information about VLANs, see Setting Up Virtual Port Features Ports operating at 1000 Mbps support full duplex mode only Port Features Switch units connected using an aggregated link Aggregated Links Traffic Distribution and Link Failure on Aggregated Links 2 Gbps aggregated link between two Switch units Optimizing Bandwidth Using Multicast Filtering Relevant multicast group Using Multicast Filtering Snooping Mode Query modeQuery Mode Igmp v2 protocol That support IPIgmp multicast filtering works as follows Enabling Igmp Multicast Learning Igmp Multicast Filtering Using Multicast Filtering Protocol STP Spanning TreeNetwork Ieee 802.1w standard What is STP? Traffic flowing through Bridge B Port Speed Link Type Path Cost 802.1D-1998 802.1w Using Resilience Features Port costs in a network Configuration 2 Redundancy through Meshed Backbone Configuration 1 Redundancy for Backbone LinkConfiguration 3 Redundancy for Cabling Error STP configurations Default Behavior Using STP on aNetwork with Multiple VLANs Configuration that separates VLANs Using Resilience Features What is the Switch How SwitchDatabase? Database Entries Switch Database Entry States Databases entries can have three states What is Traffic Prioritization?Available Converged network applications Used by organizations with a 802.1D Priority Levels How Traffic Prioritization Works Your Switch Traffic Prioritization How traffic is processed to provide Quality of Service Configuring traffic prioritization for QoS on a Switch Using Traffic Prioritization Network efficiency and reduce the load on your network What is RMON?That allows you to monitor the traffic of LANs or VLANs Events AlarmsIt improves your efficiency Switch Rmon Low Threshold Statistic High Threshold Recovery Period Low Threshold Statistic High Threshold Recovery Status Monitoring and Statistics Hardware Status Monitoring Example device summary web Setting UP Virtual Lans VLANs ease the movement of devices on networks VLANs provide extra security VLANs help to control traffic Membership Creating an Ieee 802.1Q Tagged Link Two Vlans connected via a router Configuration Using UntaggedConfigure the VLANs Examples Add endstation ports on Switch 1 to the VLANs Configure the VLANs on SwitchAdd ports to the VLANs Add port 12 on Switch 1 to the VLANs Add endstation ports on Switch 2 to the VLANsAdd port 11 on Switch 2 to the VLANs Check the Vlan membership for both switches Configuration How Your Switch Obtains IPInformation How Automatic IP How Automatic IP Configuration Works That a Switch may change its IP address whilst in use Automatic IP configuration featureConsiderations Configuration Rules IP AddressingGlossary IndexPage Configuration Rules Configuration Rules for Gigabit Ethernet Fast Ethernet configuration rules Configuration Rules for Fast Ethernet Appendix a Configuration Rules Network This chapter contains the following sections Segments are connected to the Switch which is positioned Simple NetworkFamily and 4900 family can be used in your network Example Dual Speed Hub Switch Advanced Network ImprovingResilience of Your Network Performance EnhancingTherefore the overall network performance IP Addresses Simple Overview Obtaining a Registered IP Address IP Address Decimal value of an octet whose bits are all 1s is Dotted Decimal NotationNetwork Portion Subnet mask Subnet Mask Numbering Extending the Network Prefix Or leave the field blank Glossary Glossary Endstation EthernetEthernet address Fast Ethernet Gateway Half duplexHub Ieee 802.1D Line speed See baud Glossary Rstp See Rapid Spanning Tree Protocol STP See Spanning Tree Protocol STP Page Glossary Index Numbers Igmp multicast filtering 30 Internet Addresses 85 InterNIC Sub-networks. See subnets Switch Database