Bridging 105 | EXP Computer S200 guide

LLC2 Local Termination

Traffic Priority & You can significantly optimize your spoofing operations by prioritizing Local Local Termination Termination traffic and regular bridge traffic. By assigning a separate lower priority

to spoofer traffic, the regular bridge traffic is queued quicker. The extra delay of spoofer traffic does not affect the acknowledgments of frames on the LAN.

See ““Configuring Local Termination” section on page 106” for details on setting the LLC LT WAN Data Priority parameter record.

Bridging

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EXP Computer S200 manual Bridging 105

Contents

3Com Corporation Restricted Rights Legend Restricted Rights Notification for U.S. Government Users Proprietary Material Page Overview SolutionsFunctionality Multiple LANs Bridging TranslationalNo Local Bridging Transparent This Manual Topic This Notice Topic Switches Bridging Features and CapabilitiesIntroduction Bridging Primer Ethernet LAN Ethernet Bridge ExampleOperation WAN application, but you can also bridge across an X.25 WAN Mixed LAN Bridging MAC Addressing LLC2 Local LLC2 Local TerminationTermination LT Example Autolearn for Local Termination Filtering NetBIOS NameMac Address Filtering Spanning Tree Protocol What Is It? Automatic Manual Spanning Tree Support Dual Ethernet LANs Across a WAN Basic Remote Bridging ExamplesWAN or Permanent Virtual Circuit PVC for Frame Relay Example of Bridges in an SVC Arrangement Connections BridgeLAN Interface Support Bridging Interface Connections Between WAN and LAN Setting Up WAN Operation for Bridging Setting Up WAN Operation for Bridging Configure Parameters Bridge ParametersThese parameters make up the Bridge Parameter Record Maximum Number of Bridge Links Stpe Control Bad Hello TimeoutAUTO, MAN MAN Aging Period used for Ethernet only Learn Only Period used for Ethernet onlyBridge WAN Data Priority used for Ethernet only Bridged Protocols Bridge Link Parameters Parameters control the characteristics of this connectionBridge links as links to the networks attached to it Bridge Link Entry Number These parameters make up the Bridge Link RecordBridgeType SR, TB, Bothsrandtb Largest Frame Size Hop Count LimitMAC Address Filter Action NONE, PASS, Block Protocol Filter Action Netbios Name Filter ActionStpe Link State NORMAL,RFC1294, Trans Link ModeNormal Virtual Ring Number Over the WAN LAN Connection TableLAN Connection Table Parameters ROUT, BRID, Brout LAN Forwarder TypeRout LAN Connection Type Codex Encapsulation TypeAutocall Mnemonic Lcon Queue Limit OFF, on Billing RecordsOFF Traffic Priority Limiting Bridge Frame Sizes Where bridging is done remotely across a WANOverview Transmission times for large frames become significant Sizes Standard FrameMaximum frame size Max Frame Size Line Speed Range kbps Configuring Translational Bridging Translational Bridging Example Bridge Frame Handling Configuring Configuring Source Route Bridging OperationNode for SRB Individual Bridge Bridging Procedure Connecting a Station to a Server in Source Route BridgingLAN for a Source Route Bridging operation Located on remote LAN CCC Figure Server’s Destination MAC Address Not on LAN AAA LAN Bridge Link WAN Adapter Transmits Each are Frame Across the WAN Server Responds with Specifically Routed Test Frame Then Step Action Result/Description Learning Transparent Bridging for Ethernet LANsForwarder Forwarder Example LAN link WAN link Link errorStatistics Filtering Accelerator LAN/WAN Handlers HardwareHardware Accelerator Functions Forwarder Functions Forwarder Initialization Aging Learn Only Period Forwarder Database and Spanning Tree Using Filters Frame is dropped Multicast LinkList, the frame is dropped Control menu located in the Main menu TB Forwarding Transparent Bridge Configuration ParametersLocal MAC Address Bridge Link Number Bridge Filtering What is It? How Filtering is Used Parameter Action MAC Address Filtering Parameter Action Value Parameter Process MAC Filtering Example of a Frame Passing on a Bridge Link Mac Filtering Process Incoming and Outgoing Frames Configuring the Bridge Link Record How To Configure ExampleMAC Address Filtering Examples First Example Configuring the MAC Address Filter Table Identifying Address Links for MAC Addressing Why it is ImportantAddress Links MAC Wildcard Filtering Series Switch SupportFiltering works Broadcast frames in the LAN network Configuring the MAC Address Filter TableCategories Incoming Source Address Link Action These parameters make up the MAC Address Filter TablePASS, BLOCK, PASSLIST, Blocklist Pass Incoming Destination Address Link Action Outgoing Source Address Link Action List of Links Outgoing Destination Address Link Action Protocol Filtering These parameters make up the Protocol Filter Table Record Protocol Filter Protocol SAP hex value Protocol TypeProtocol OUI/IP hex value Protocol Value Outgoing Protocol Link Action Incoming Protocol Link Action Dsap Values Parameter Actions Broadcasts to and from the SVR* name pattern NetBIOS Name FilteringTransparent Bridging Forcing a Local Checking NetBIOSDomain With Filters How to Configure Configuring NetBIOS Name FilteringNetBIOS Name Filtering Step Action Step Action Result Select Configure ConfigureEntry Number 1 appears Bridge Bridge Link NetBIOS Name Filter Table Configure NetBIOSBridge -NetBIOS Name Filter Name Filter Table String Type Typical FilteringAscii Incoming NetBIOS Name List of Links Incoming NetBIOS Name Link Action Outgoing NetBIOS Name List of LInks Outgoing NetBIOS Name Link Action NetBIOS broadcasts filtered on the link NetBIOS Name Filtering StatisticsEach bridge link Check Detailed IBM NetBIOS Formats When to Use NetBIOS Name Filtering NetBIOS Packet FormatsAll of the following are true Either one of the following is true Spanning Tree Protocol Entity Stpe Configuration Stpe Control= Auto Stpe Control = Manual MenuSpanning Tree Tree Bridge Links Spanning Tree Protocol Entity Stpe Example of a Stpe Parameter Setting ConsiderationsBridge Network Bridge ID equals Bridge Priority Value in hex + MAC Address Setting the Root Bridge Spanning TreeDetermining Root Links Designated Links Type of Network Speed Stpe Path Cost Nature ConsiderExpected Number SVCs Two Bridge Links Between B3 and B4 Spanning Tree Protocol Entity Stpe Timer Parameters Spanning Tree TimersHello Timer Max Age Considerations Other Message Events in Network Bridge Forward Delay Timer Spanning Tree Protocol Entity Stpe Bridges can adjust to the change Aging TimerLocation and forwards packets to it properly LLC2 Local Termination Preventing session timeouts in a Bridging application Terminal session, causing Well as network delaysBefore Local After Local Topologies SupportedImproper LT LLC Protocol LLC Frame Description LLC2 Frame Description Proper LT configurationType Name Description Local Termination does not spoof Local Termination spoofs Bridging 105 Local Termination Configuring Local Termination Step Boot Type LLC LT StationStation Table Entry Number T2 Rx Ack Timer WAN Parameters T1Reply TimerLocal SAP LLC Profile Name Ti Inactivity Timer Boot Type LLC LT WAN ParametersN3 ACK Delay Count N2 Retry Count Tx Window Size Configuration Entry NumberLCC LT WAN Data Priority HIGH, MEDIUM, LOW T1 Reply Timer 112 Bridging Deleting LT Configuration Records Mixed LAN Operation 27x switch, as shown in FigureMixed LAN Environment Limitations Bridge Link Parameters menu Select Configure BridgeBridge Link Parameters from CTP Main menu, to activate Bridge link Bothsrandtb Dual LAN Ethernet System powerup Supported RoutingDual Ethernet LAN Cmem Parameters For Details on LAN Server Subsystem Alarms Example of LCC Configuring the LSS RecordRecord Virtual Port’s MAC Address Disable ENABLE, DisableVirtual Bridge ID Path Trace Control Statistics Menu screen Bridge Statistics Stpe Status Spanning Tree StatisticsStatus report Term Description State Disabled The Stpe is disabled. If Stpe ControlAre Parameter is MAN Detailed Bridge Link Statistics First Detailed Bridge Link Statistics Screen Terms RIF Link Filter Bridge Link Filter SummarySummary Description Bridging 131 Stats Example Transparent Bridge Forwarding Table StatisticsStats Descriptions Shown in Figure Bridging 133 Terms-Transparent Bridge Second Transparent Bridge Detailed Bridge Link Statistics Frame Totals This is a count of the number of frames FF-FF-FF-FF-FF-FFReceived/transmitted of all types on this link Statistics Menu LAN Connection StatisticsDetailed LAN Connection Statistics Detailed LAN Connection Statistics Second Last clear diagnostic code This is the diagnostic code Explains why the last call was clearedConnection and explains why the call was cleared SVCs. The possible states are Blank for PVCs blank Bridging 139 Connection Summary Statistics Example of LAN shows the LAN Connection Summary Statistics Heading Description LLC2 LT Session Summary StatisticsSAP Remote MAC Addr Heading Session Statistics LLC2 LT Detailed Session Statistics Routing information field used in all frames transmitted Last Statistics Last time statistics were reset ResetField, ring number, and bridge number information Heading Description Local Station Session Summary Heading Description Remote Spoofer Session Summary Reset Statistics 148 Bridging Technical Support 3ComFacts Automated Fax Service Access by Analog ModemAccess by Digital Modem Country Data Rate Telephone Number 3Com Support fromCountry Telephone Number Country Telephone Number Fax Number Numerics Index LAN OUI URL A-1 Index-5