Creating a Stable STP Topology | D-Link DES-3326S specification

DES-3326S Layer 3 Fast Ethernet Switch User’s Guide

which the packet is transmitted will receive the BPDU. BPDUs are not directly forwarded by the switch, but the receiving switch uses the information in the frame to calculate a BPDU, and, if the topology changes, initiates a BPDU transmission.

The communication between switches via BPDUs results in the following:

•One switch is elected as the root switch

•The shortest distance to the root switch is calculated for each switch

•A designated switch is selected. This is the switch closest to the root switch through which packets will be forwarded to the root.

•A port for each switch is selected. This is the port providing the best path from the switch to the root switch.

•Ports included in the STP are selected.

Creating a Stable STP Topology

If all switches have STP enabled with default settings, the switch with the lowest MAC address in the network will become the root switch. By increasing the priority (lowering the priority number) of the best switch, STP can be forced to select the best switch as the root switch.

When STP is enabled using the default parameters, the path between source and destination stations in a switched network might not be ideal. For instance, connecting higher-speed links to a port that has a higher number than the current root port can cause a root-port change. The goal is to make the fastest link the root port.

62	Switch Management and Operating Concepts

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D-Link DES-3326S manual Creating a Stable STP Topology

Contents

DES-3326S Wichtige Sicherheitshinweise Page Warranties Exclusive Hardware Software Page Copyright Statement Link Offices for Registration and Warranty ServiceTrademarks Vcci Warning Bsmi Warning FCC WarningCE Mark Warning Viii Table of Contents Snmp Using WEB-BASED Management Xii Layer 3 Switching Introduction Introduction Functions of a Layer 3 Switch Layer 2 Features FeaturesPerformance Features Ports DES-3326S Layer 3 Fast Ethernet Switch User’s Guide Layer 3 Switch Features Traffic Classification and Prioritization Management Supports Web-based management Switch Stacking Fast Ethernet Technology Gigabit Ethernet Technology Unpacking and Setup Unpacking Installation Desktop or Shelf Installation Rack Installation Installing rubber feet for desktop installation Power on 2B. Installing the switch on an equipment rack Power Failure Identifying External Components Front Panel Rear panel view of the Switch Rear Panel Side Panels Optional Plug-in Modules 100BASE-FX Fiber Module 2Km/15Km 1000BASE-T Module 1000BASE-SX Fiber Module 62.5 ∝m 1000BASE-LX Fiber Module BASE-LX two-port module Gbic Two-Port Module Stacking Module with Gbic Port Gbic Port Stacking Port 11. Up to 6 Switches in a Switch Stack Switch LED Indicators Stacking Module LED Indicators 13. Stacking Module LED Indicators Connecting Switch Switch to End Node Switch to Hub or Switch Switch connected to an End Node Switch Stack Connections Switch Stack connections between optional stacking Modules 10BASE-T Device 100BASE-TX Device Switch Management Operating Concepts Local Console Management Diagnostic console port RS-232 DCE Managing Switch Stacks Determining the Switch Stack Order Switch Stack Order − First 001122334450 2original Master Switch IP Address Console Boot Screen Setting an IP Address Traps Switch Management and Operating Concepts Snmp Snmp performs the following functions Authentication Traps DES-3326S Layer 3 Fast Ethernet Switch User’s Guide MIBs Link Change Event This trap is sent Packet Forwarding Filtering MAC Address Aging Time Some filtering is done automatically by the switch Parameter Description Default Value Spanning Tree Variable Description Default Value Bridge Protocol Data Units Creating a Stable STP Topology STP Port States Port transitions from one state to another as follows STP Port State Transitions Feature Default Value User-Changeable STA Parameters DES-3326S Layer 3 Fast Ethernet Switch User’s Guide Illustration of STP Before Applying the STA Rules After Applying the STA Rules Link Aggregation Link Aggregation Group Defaultvlan VLANs Some relevant terms Ieee 802.1Q VLANs802.1Q Vlan Packet Forwarding 802.1Q Vlan Tags Ieee 802.1Q Packet Forwarding Ieee 802.1Q Tag Port Vlan ID Adding an Ieee 802.1Q Tag Switch Management and Operating Concepts Tagging and Untagging Ingress Filtering VLANs in Layer 2 Only Mode Definitions Layer 3-Based VLANsIP Addressing and Subnetting IP Addresses 255 Binary to Decimal Conversion Address Classes Subnet Masking Calculating the Number of Subnets and Nodes Classless InterDomain Routing Cidr Class a Subnet Masks Setting up IP Interfaces 10. Class B Subnet Masks 12. Vlan Example Assigned Ports Internet Protocols Protocol Layering OSI Seven Layer Network Model Protocol Stack Layer Layer TCP/IP DES-3326S Layer 3 Fast Ethernet Switch User’s Guide Packet Headers TCP 10. TCP Packet Header Switch Management and Operating Concepts Ethernet 100 12. Ethernet Packet Header 101 TCP and UDP Well-Known Ports 102 UDP and Icmp 103 13. Ethernet Packet Header 104 Mapping Domain Names to Addresses Domain Name ResolutionDomain Name System 105 Dhcp Servers 106 IP Routing 107 Packet Fragmentation and Reassembly 108 ARP 109 110 MulticastingMulticast Groups Address Assignment 111 Internet Group Management Protocol Igmp 112 Igmp Versions 1 113 14. Igmp Type Codes 114 Multicast Routing Algorithms 115 116 FloodingMulticast Spanning Trees Reverse Path Broadcasting RPB 117 Reverse Path Multicasting RPM 118 119 Multicast Routing ProtocolsDistance Vector Multicast Routing Protocol Dvmrp Routing Information Protocol RIP Protocol-Independent Multicast Dense ModeRouting Protocols 120 121 RIP Version 1 Message Format 122 17. RIP v.1 Message Format 123 RIP 1 Message 124 RIP2 Message Format RIP 1 Route InterpretationRIP Version 2 Extensions 125 Open Shortest Path First Ospf 126 Link-State Algorithm 127 Shortest Path Algorithm 128 129 Ospf CostShortest Path Tree 19. Constructing a Shortest Path Tree 130 20. Constructing a Shortest Path Tree 131 Areas and Border Routers 132 Link-State Packets 133 134 Message Digest Authentication MD-5 Ospf AuthenticationSimple Password Authentication Backbone and Area Partitioning the Backbone Virtual LinksAreas Not Physically Connected to Area 136 Neighbors 137 Building Adjacency AdjacenciesDesignated Router Election 138 139 140 Adjacencies on Point-to-Point InterfacesOspf Packet Formats 141 Ospf Packet HeaderField Description 142 Hello Packet 143 Hello Packet 144 BDR 145 Database Description Packet 146 18. Database Description Packet 147 Link-State Request Packet 148 Link-State Update Packet 149 Link-State Acknowledgment Packet 150 Link-State Advertisement Formats 151 Link State Advertisement Header 152 Link-State Advertisement Header 153 154 Router Links Advertisements 155 Routers Links Advertisements 156 FieldDescription 157 158 159 Network Links Advertisements 160 Network Link Advertisements 161 Summary Link Advertisements 162 31. Summary Link Advertisement 163 Autonomous Systems External Link Advertisements 164 AS External Link Advertisements 165 166 Introduction 167 168 Before You StartGeneral Deployment Strategy Vlan Layout 169 Assigning IP Network Addresses and Subnet Masks to VLANs 170 Management That opens, click on the Login to DES-3326S Manager buttonGetting Started Defining Static Routes 172 Configuring the SwitchUser Accounts Management User Accounts Control Table 173 Admin and User Privileges 174 175 Configuration Mana Gement Admin UserSaving Changes Save Changes Screen 176 Factory Reset 177 Setting Up Web Management 178 Ipaddress xxx.xxx.xxx.xxx/yyy.yyy.yyy.yyy 179 Saving Configuration Changes 180 Starting and Stopping the Web-based Manager 181 Web-based Manager’s User Interface 182 Areas of the User Interface 183 Area Function 184 Switch Information Setting Up The SwitchBasic Setup Click the Switch Information link in the Configuration menu 10. Switch Information Basic Settings 186 187 IP Address Configuring the Switch’s IP AddressTo set the switch’s IP address 11. Basic Switch Setup 188 Broadcast request when it is powered New Switch IP Settings options areSwitch will send out a Bootp Up. The Bootp protocol allows IP Manual 190 Management Station IP Addresses Default GatewayVlan Name 191 192 Snmp SettingsTo setup the switch for remote management Configuring Community Strings 193 Setting Up Trap Receivers 194 Stacking Information 195 15. Switch Stack Display 196 17. Stacking Information 197 Show stacking mode/version 198 19. Console CLI show stack Command 199 200 201 Config stacking mode slaveConfig stacking mode master Configure Ports 202 22. Port Configurations − Edit 203 204 Locking a Port’s MAC Address LearningSpeed/Duplex Toggle the Speed/Duplex Auto field Serial Port Settings 205 206 Baud RateData Bits 207 Stop BitsAuto-Logout To create a new 802.1Q Vlan Advanced SetupConfiguring VLANs 208 To create a new 802.1Q VLAN, click the New button 209 26 .1Q Static VLANs Entry Settings Edit 210 Untagged PortTagged/Untagged Egress 212 Ingress Filter 213 To enable or disable GVRP, globally, on the switch 214 Layer 3 IP Networking 215 To setup IP Interfaces on the switch 216 217 To setup an new IP interface, click the New buttonTo edit an existing IP interface, click on the Edit button 218 Interface NameIP Address Subnet Mask Setup the Routing Information Protocol RIPSwitch Active Yes 32. RIP Status 220 221 TX Mode DisabledRX Mode MD5 Key Table Configuration 222 223 Key IDKey Setup Ospf 224 State Ospf Area SettingCurrent Route ID AS Border Router 225 Area ID Default Cost Stub ImportStub Default Cost Type 227 Ospf Interface ConfigurationRemove 228 Router PriorityHello Interval 229 Auth TypeSimple Auth Key Ospf Interface Configuration − MonitorKey Configuration Metric Virtual Interface Configuration 231 232 Neighbor RouterStatus Area Aggregation Configuration 233 Route Redistribution Settings 234 Protocol Source ProtocolDestination Metric Type 236 IP Multicasting 237 State Disabled Igmp Snooping SettingsTo configure Igmp Snooping 238 Max Response Igmp Interface ConfigurationQuery Robustness Var 46. Igmp Interface Setup 240 241 VersionQuery Interval Time Dvmrp Interface ConfigurationMax Response Robustness 49. Dvmrp Interface Configuration − Edit 243 Probe Interval InterfaceName System 244 State Disabled PIM-DM SettingsNeighbor Timeout Interval Metric 50. PIM-DM Interface Configuration 246 51. PIM-DM Interface Configuration − Edit 247 Interval Static Router Port SettingsJoin/Prune 248 To setup a static router port 249 53. Static Router Port Settings − Add 250 251 To configure a port for port mirroringPort Mirroring 252 Source PortDirection Ingress 253 To configure a forwarding priority for a given MAC addressPriority 56. MAC Address Priority − Add 254 Source/Destinatio MAC AddressUser Priority 255 IP Address Filtering 256 0.0 257 258 Forwarding 259 Unicast MAC Address Forwarding 260 63. Unicast MAC Address Settings − Add 261 262 Multicast MAC Address ForwardingUnit 65. Multicast MAC Address Settings 263 None 264 IP Forwarding 265 266 To add a new static/default route, click the New buttonGateway IP 267 Static ARPTo add a new static ARP entry, click the New button STP Switch Settings 268 72. STP Switch Settings 269 270 STP Port Settings 271 73. STP Port Settings 272 273 CostPriority 274 74. Link Aggregation 275 Following fields can be set 276 Tftp Utilities Update Firmware from ServerUtilities Port Member 77. Download Firmware from Server 278 Use Configuration File on Server 279 280 Save Settings To ServerSave History Log to Server Utilities BOOTP/DHCP Relay 281 Relay Time Threshold Bootp Hops Count LimitRelay Status 282 To add a new entry, click the New button 283 284 To configure DNS Relay, click on the DNS Relay linkDNS Relay 285 0.0 To add a new entry to the table, click on the New buttonAddress The IP address of the domain name Above 287 Network MonitoringPort Utilization 87. Port Utilization window 288 289 Port Error StatisticsUpdate 88. Port Error Packet Statistics window 290 RX Frames Update IntervalCRC Error Undersize Excessive Deferral Drop PacketsTX Frames Late Collision Port Packet Analysis 293 Unicast RX FramesFrames/sec Frames/sec Multicast RX Total/sec TX Frames MAC Address TableTotal/sec TX Bytes Total/sec IP Address Table 296 297 91. IP Address Table 298 Routing Table Netmask 300 301 To view the switch’s ARP table, click on the ARP Table linkARP Table 93. ARP Table 302 303 Ospf Link State Database TableArea ID Displays the Ospf Area ID Sequence 304 305 Ospf Neighbor TablePriorityrouter Ospf Virtual Neighbor Table Dvmrp Neighbor Address Table 307 Name Gvrp StatusLearned Expire 309 Router PortsIgmp Snooping Status 100. Igmp Snooping Table 310 IP Multicast Forwarding Table 311 312 Igmp Group TableProtocol Routing protocol in use 313 Dvmrp Routing TableQuerier IP Click the Switch History link on the Applications menu Switch HistoryTo view the switch history log 314 104. Switch History 315 Technical Specifications 316 Physical and Environmental 317 318 EMI Understanding Troubleshooting Spanning Tree Protocol 319 Blocking State Port in the blocking state does the following 321 Listening State Port in the listening state does the following 323 Learning State Port in the learning state does the following 325 Forwarding State Port in the forwarding state does the following 327 Disabled State Disabled port does the following 329 Troubleshooting STP Spanning Tree Protocol Failure Full/Half Duplex Mismatch 331 Unidirectional Link 333 Resource Errors Packet Corruption Avoiding Trouble Know where the root is locatedIdentifying a Data Loop Know which links are redundant Minimize the number of ports in the blocking state 337 Understanding and Troubleshooting the Spanning Tree Protocol Impact of Layer 3 Switching 339 Understanding and Troubleshooting the Spanning Tree Protocol 341 Brief Review Bitwise Logical Operations Not Index Spanning Tree Protocol Vlan Offices Registration Card