Default Behavior, Using STP on a, Network with | 3Com 3 specification

42CHAPTER 4: USING RESILIENCE FEATURES

Default Behavior	This section contains important information to note when using the RSTP
	and Fast Start features, particularly if you already have existing Switch
	4200 units in your network with an older version of software.
RSTP Default	When using the RSTP feature, note that the Switch will have RSTP
Behavior	enabled by default.
Fast Start Default	When using the Fast Start feature note that the Switch will have Fast Start
Behavior	enabled by default.

Using STP on a	The IEEE 802.1D standard does not take into account VLANs when it
Network with	calculates STP information — the calculations are only performed on the
Multiple VLANs	basis of physical connections. For this reason, some network
	configurations can result in VLANs being subdivided into a number of
	isolated sections by the STP system. Therefore, you must ensure that any
	VLAN configuration on your network takes into account the expected STP
	topology and alternative topologies that may result from link failures.
	For example, Figure 10 shows a network containing VLANs 1 and 2. They
	are connected using the 802.1Q-tagged link between Switch B and
	Switch C. By default, this link has a path cost of 100 and is automatically
	blocked because the other Switch-to-Switch connections have a path cost
	of 36 (18+18). This means that both VLANs are now subdivided — VLAN
	1 on Switch units A and B cannot communicate with VLAN 1 on Switch
	C, and VLAN 2 on Switch units A and C cannot communicate with
	VLAN 2 on Switch B.

Image 42

3Com 3 manual Default Behavior, Using STP on a, Network with, Multiple VLANs

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 Comments RelatedDocumentation Pddtechpubscomments@3com.com Product Registration Switch Features Page Management What isSwitch Features Software? Switch Features Overview Duplex Ports operating at 1000 Mbps only support full duplex modeFor more information about multicast filtering, see Using 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 multicast filtering works as follows Igmp v2 protocolThat support IP 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 Network with Default BehaviorUsing STP on a Multiple VLANs Configuration that separates VLANs Using Resilience Features Database? What is the SwitchHow Switch Database Entries Switch Database Entry States Databases entries can have three states Available What is TrafficPrioritization? 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 Configure the VLANs ConfigurationUsing Untagged Examples Configure the VLANs on Switch Add endstation ports on Switch 1 to the VLANsAdd ports to the VLANs Add port 11 on Switch 2 to the VLANs Add port 12 on Switch 1 to the VLANsAdd endstation ports on Switch 2 to the VLANs Check the Vlan membership for both switches Configuration Information How Your SwitchObtains IP How Automatic IP How Automatic IP Configuration Works Automatic IP configuration feature That a Switch may change its IP address whilst in useConsiderations Glossary Configuration RulesIP Addressing 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 Family and 4900 family can be used in your network Segments are connected to the Switch which is positionedSimple Network Example Dual Speed Hub Switch Resilience of Your Advanced NetworkImproving 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 Ethernet address EndstationEthernet Fast Ethernet Hub GatewayHalf duplex 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