Ethernet LAN | EXP Computer S200 manual

Bridging Features and Capabilities

Ethernet LAN

What Is It?	Ethernet is a common implementation of LAN topology wherein stations are
	connected using a bus topology. Stations access the Ethernet using Carrier Sense
	with Multiple Access and Collision Detection (CSMA/CD).
PathBuilder S200
	PathBuilder S200 series switch Ethernet functionality complies with the IEEE 802.3
Series Switch	specifications and provides Transparent Bridging to transport many different
Support for	protocols over the Wide Area Network (WAN) to remote destinations. Supported
Ethernet	protocols include:
	•	Novell Netware
	•	DECnet
	•	Banyan Vines
Example of Basic
	Figure 3 shows the basic frame formats for Ethernet frames supported by
Ethernet Frame	PathBuilder S200 series switches.
Format

Ethernet Frame Format

Preamble	Destination	Source	Type	Data	FCS

8	6	6	2	45-1500	4

Octets

64-1518

Figure 3. Frame Format for Ethernet Frames

802.3MAC Frame Figure 4 shows the supported 802.3 Ethernet MAC Frame format.

Format

802.3MAC Frame Format

Preamble SFD Destination Source Len Data Unit Pad FCS

DSAP

SSAP

Control

Higher Layer Information

1

1

1 or 2

42-1497

802.3.LLC

Octets

Figure 4. 802.3 Ethernet MAC Frame Format Example

6

Bridging

Image 10

EXP Computer S200 manual Ethernet LAN

Contents

3Com Corporation Restricted Rights Notification for U.S. Government Users Restricted Rights Legend Proprietary Material Page Functionality SolutionsOverview Multiple LANs No Local Bridging TranslationalBridging Transparent This Manual Topic This Notice Topic Introduction Bridging Features and CapabilitiesSwitches Bridging Primer Ethernet LAN Operation ExampleEthernet Bridge WAN application, but you can also bridge across an X.25 WAN Mixed LAN Bridging MAC Addressing Termination LLC2 Local TerminationLLC2 Local LT Example Autolearn for Local Termination Mac Address NetBIOS NameFiltering Filtering What Is It? Automatic Manual Spanning Tree Support Spanning Tree Protocol 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 LAN Interface BridgeConnections Support Bridging Setting Up WAN Operation for Bridging Interface Connections Between WAN and LAN Setting Up WAN Operation for Bridging Configure These parameters make up the Bridge Parameter Record Bridge ParametersParameters Maximum Number of Bridge Links AUTO, MAN Bad Hello TimeoutStpe Control MAN Aging Period used for Ethernet only Learn Only Period used for Ethernet onlyBridge WAN Data Priority used for Ethernet only Bridged Protocols Bridge links as links to the networks attached to it Parameters control the characteristics of this connectionBridge Link Parameters Bridge Link BridgeType These parameters make up the Bridge Link RecordEntry Number SR, TB, Bothsrandtb MAC Address Filter Action Hop Count LimitLargest Frame Size NONE, PASS, Block Protocol Filter Action Netbios Name Filter ActionStpe Link State Normal Link ModeNORMAL,RFC1294, Trans Virtual Ring Number LAN Connection LAN Connection TableOver the WAN Table Parameters Rout LAN Forwarder TypeROUT, BRID, Brout LAN Connection Type Autocall Mnemonic Encapsulation TypeCodex Lcon Queue Limit OFF Billing RecordsOFF, on Traffic Priority Overview Where bridging is done remotely across a WANLimiting Bridge Frame Sizes Transmission times for large frames become significant Maximum frame size Standard FrameSizes Max Frame Size Line Speed Range kbps Configuring Translational Bridging Translational Bridging Example Bridge Frame Handling Node for SRB Configuring Source Route Bridging OperationConfiguring Individual Bridge Bridging LAN for a Source Route Bridging operation Connecting a Station to a Server in Source Route BridgingProcedure 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 Step Action Result/Description Then Learning Transparent Bridging for Ethernet LANsForwarder Statistics LAN link WAN link Link errorForwarder Example Filtering Accelerator LAN/WAN Handlers HardwareHardware Accelerator Functions Forwarder Functions Forwarder Initialization Learn Only Period Aging Forwarder Database and Spanning Tree Using Filters List, the frame is dropped Multicast LinkFrame is dropped Control menu located in the Main menu Local MAC Address Transparent Bridge Configuration ParametersTB Forwarding Bridge Link Number What is It? How Filtering is Used Bridge Filtering MAC Address Filtering Parameter Action Parameter Parameter Action Value MAC Filtering Process Mac Filtering Process Incoming and Outgoing Frames Example of a Frame Passing on a Bridge Link MAC Address Filtering Examples How To Configure ExampleConfiguring the Bridge Link Record 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 PASS, BLOCK, PASSLIST, Blocklist These parameters make up the MAC Address Filter TableIncoming Source Address Link Action Pass Outgoing Source Address Link Action Incoming Destination Address Link Action Outgoing Destination Address Link Action List of Links Protocol Filtering Protocol Filter These parameters make up the Protocol Filter Table Record Protocol OUI/IP hex value Protocol TypeProtocol SAP hex value Protocol Value Incoming Protocol Link Action Outgoing Protocol Link Action Dsap Values Parameter Actions Broadcasts to and from the SVR* name pattern NetBIOS Name FilteringTransparent Bridging Domain With Checking NetBIOSForcing a Local Filters NetBIOS Name Filtering Configuring NetBIOS Name FilteringHow to Configure Step Action Entry Number 1 appears Select Configure ConfigureStep Action Result Bridge Bridge Link Bridge -NetBIOS Name Filter Configure NetBIOSNetBIOS Name Filter Table Name Filter Table String Type Typical FilteringAscii Incoming NetBIOS Name Link Action Incoming NetBIOS Name List of Links Outgoing NetBIOS Name Link Action Outgoing NetBIOS Name List of LInks Each bridge link NetBIOS Name Filtering StatisticsNetBIOS broadcasts filtered on the link Check Detailed All of the following are true NetBIOS Packet FormatsIBM NetBIOS Formats When to Use NetBIOS Name Filtering Either one of the following is true Spanning Tree Configuration Stpe Control= Auto Stpe Control = Manual MenuSpanning Tree Protocol Entity Stpe 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 Expected Number ConsiderNature SVCs Two Bridge Links Between B3 and B4 Spanning Tree Protocol Entity Stpe Hello Timer Spanning Tree TimersTimer Parameters Max Age Other Considerations Bridge Forward Delay Timer Message Events in Network Spanning Tree Protocol Entity Stpe Bridges can adjust to the change Aging TimerLocation and forwards packets to it properly Preventing session timeouts in a Bridging application LLC2 Local Termination Before Local Well as network delaysTerminal session, causing After Local Topologies SupportedImproper LT LLC Protocol LLC Frame Description LLC2 Frame Description Proper LT configurationType Name Description Local Termination spoofs Local Termination does not spoof Bridging 105 Configuring Local Termination Local Termination Step Boot Type LLC LT StationStation Table Entry Number Local SAP WAN Parameters T1Reply TimerT2 Rx Ack Timer LLC Profile Name N3 ACK Delay Count Boot Type LLC LT WAN ParametersTi Inactivity Timer N2 Retry Count LCC LT WAN Data Priority Configuration Entry NumberTx Window Size 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 from Select Configure BridgeBridge Link Parameters menu CTP Main menu, to activate Bridge link Bothsrandtb System powerup Dual LAN Ethernet Dual Ethernet LAN RoutingSupported Cmem For Details on Parameters LAN Server Subsystem Alarms Record Configuring the LSS RecordExample of LCC Virtual Port’s MAC Address Virtual Bridge ID ENABLE, DisableDisable Path Trace Control Bridge Statistics Statistics Menu screen Status report Spanning Tree StatisticsStpe Status Term Description Are Disabled The Stpe is disabled. If Stpe ControlState Parameter is MAN Detailed Bridge Link Statistics Detailed Bridge Link Statistics First Screen Terms RIF Summary Bridge Link Filter SummaryLink Filter Description Bridging 131 Stats Descriptions Transparent Bridge Forwarding Table StatisticsStats Example Shown in Figure Bridging 133 Transparent Bridge Detailed Bridge Link Statistics Terms-Transparent Bridge Second 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 Connection and explains why the call was cleared Explains why the last call was clearedLast clear diagnostic code This is the diagnostic code SVCs. The possible states are Blank for PVCs blank Bridging 139 Example of LAN shows the LAN Connection Summary Statistics Connection Summary Statistics SAP LLC2 LT Session Summary StatisticsHeading Description Remote MAC Addr Heading LLC2 LT Detailed Session Statistics 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 Access by Digital Modem Access by Analog Modem3ComFacts Automated Fax Service Country Data Rate Telephone Number 3Com Support fromCountry Telephone Number Country Telephone Number Fax Number Index Numerics LAN OUI URL A-1 Index-5