Traffic Distribution and Link Failure on Aggregated Links | 3Com 3

24CHAPTER 2: OPTIMIZING BANDWIDTH

Traffic Distribution and Link Failure on Aggregated Links

To maximize throughput, all traffic is distributed across the individual links that make up an aggregated link. Therefore, when a packet is made available for transmission down an aggregated link, a hardware-based traffic distribution mechanism determines which particular port in the link should be used; this mechanism uses the MAC address. The traffic is distributed among the member links as efficiently as possible.

To avoid the potential problem of out-of-sequence packets (or “packet re-ordering”), the Switch ensures that all the conversations between a given pair of endstations will pass through the same port in the aggregated link. Single-to-multiple endstation conversations, on the other hand, may still take place over different ports.

If the link state on any of the ports in an aggregated link becomes inactive due to link failure, then the Switch will automatically redirect the aggregated link traffic to the remaining ports. Aggregated links therefore provide built-in resilience for your network.

The Switch also has a mechanism to prevent the possible occurrence of packet re-ordering when a link recovers too soon after a failure.

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3Com 3 manual Traffic Distribution and Link Failure on Aggregated Links

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 Quality of Service For more information about Quality of Service, see UsingEvent 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 Query mode Snooping ModeQuery Mode Igmp v2 protocol That support IPIgmp multicast filtering works as follows Enabling Igmp Multicast Learning Igmp Multicast Filtering Using Multicast Filtering Spanning Tree Protocol STPNetwork 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 1 Redundancy for Backbone Link Configuration 2 Redundancy through Meshed BackboneConfiguration 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 What is RMON? Network efficiency and reduce the load on your networkThat allows you to monitor the traffic of LANs or VLANs Alarms EventsIt 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 Configure the VLANs on Switch Add endstation ports on Switch 1 to the VLANsAdd 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 Automatic IP configuration feature That a Switch may change its IP address whilst in useConsiderations 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 Enhancing PerformanceTherefore the overall network performance IP Addresses Simple Overview Obtaining a Registered IP Address IP Address Dotted Decimal Notation Decimal value of an octet whose bits are all 1s isNetwork 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