Configuration 1 Redundancy for Backbone Link | 3Com 3 manual

40CHAPTER 4: USING RESILIENCE FEATURES

■Bridge C has been selected as the Designated Bridge for LAN segment 3, because it offers the lowest Root Path Cost for LAN Segment 3:

■the route through Bridges C and B costs 200 (C to B=100, B to A=100)

■the route through Bridges Y and B costs 300 (Y to B=200, B to A=100).

Port 2 on Bridge C is therefore selected as the Designated Bridge Port for LAN Segment 3.

STP Configurations Figure 9 shows three possible STP configurations using SuperStack 3 Switch units.

■Configuration 1 — Redundancy for Backbone Link

In this configuration, the Switches both have STP enabled and are connected by two links. STP discovers a duplicate path and blocks one of the links. If the enabled link breaks, the disabled link becomes re-enabled, therefore maintaining connectivity.

■Configuration 2 — Redundancy through Meshed Backbone

In this configuration, four Switch units are connected in a way that creates multiple paths between each one. STP discovers the duplicate paths and blocks two of the links. If an enabled link breaks, one of the disabled links becomes re-enabled, therefore maintaining connectivity.

■Configuration 3 — Redundancy for Cabling Error

In this configuration, a Switch has STP enabled and is accidentally connected to a hub using two links. STP discovers a duplicate path and blocks one of the links, therefore avoiding a loop.

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3Com 3 manual Configuration 1 Redundancy for Backbone Link, Configuration 2 Redundancy through Meshed Backbone

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