Enterasys Networks VH-4802 manual Feature Summaries, Ieee 802.1D Bridge, Spanning Tree Protocol

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Feature Summaries

The following summaries describe VH-4802 features in areas such as standards compliance, functionality, performance, and options.

IEEE 802.1D Bridge

The VH-4802 switch is fully compliant with IEEE 802.1D transparent bridging specifications. An address table is provided for learning, filtering, and forwarding. The switch can support up to a maximum of 12K addresses. Addresses are automatically learned by the switch, and can be individually assigned specific forwarding treatment by the network administrator if desired. Forwarding table configuration can be made out- of-band via the console interface or in-band via SNMP or Telnet. Static and dynamic addresses are both stored in this table. One static address is assigned per port by default. The Static Unicast Address Table Configuration screen in the console menus allows you to assign additional static addresses if required.

Spanning Tree Protocol

The VH-4802 switch supports the IEEE 802.1D Spanning Tree Protocol. This protocol allows redundant connections to be created between different LAN segments for purposes of fault tolerance. Two or more physical paths between different segments can be created through the switch, with the Spanning Tree Protocol choosing a single path at any given time and disabling all others. If the chosen path fails for any reason, a disabled alternative is activated, thereby maintaining the connection. This prevents network traffic from circulating in an endless loop formed by multiple connections to the same LAN segment.

Spanning Tree parameters are configurable using the Spanning Tree Configuration Menu of the console menus, the on-board Web agent, or via SNMP (see Appendix B, “Spanning Tree Concepts,” in the Management Guide for more information).

Frame Buffering and Frame Latency

The VH-4802 switch is a store-and-forward switching device. Each frame is copied into switch memory before being forwarded to another port. This method ensures that all forwarded frames conform to a standard Ethernet frame size and have a correct cyclic redundancy check (CRC) for data integrity. This switching method prevents bad frames from traversing the network and using up valuable network bandwidth, as with cut-through switching technology.

To minimize the possibility of dropping frames on congested ports, the VH-4802 switch provides 512 KB of frame buffering per port. This buffer space is used to queue packets for transmission on congested networks. This is an additional advantage over cut-through switching technology, which drops packets immediately when experiencing collisions.

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Product Overview 7

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Contents User Guide Fast Ethernet SwitchPage 9033630 FCC Notice Warnhinweis Faseroptikanschlüsse Optische Sicherheit Safety Information Wichtige Sicherheitshinweise Germany Enterasys NETWORKS, INC Program License Agreement 9033630 Declaration of Conformity Viii Table of Contents Index Purpose PrefaceAudience ConventionsOther Conventions OrganizationDescription Product OverviewFeatures Tftp Front Panel Components Front PanelOptional Modules Optional Module Components Optional ModulesRear Panel Components Rear PanelIeee 802.1D Bridge Feature SummariesSpanning Tree Protocol Frame Buffering and Frame LatencyConfiguration and Management Interfaces Software DownloadNon-Volatile Parameter Storage Port Mirroring RmonFull Duplex Mode BootPAuto-negotiation LEDsFlow Control Class of ServiceVirtual LANs VLANs Port TrunkingFactory Default Settings Factory DefaultsGvrp Application Examples Client/Server Network Application Client/Server Network ApplicationLocal Backbone Application Local Backbone ApplicationInstallation Inspecting Your ShipmentSite Requirements Mounting the Switch on a Table or Shelf Mounting the Switch in a Rack Mounting the Switch in a RackInstalling an Optional Module into the Switch Installing an Optional Module into the SwitchConsole Port Out-of-Band Connections Connecting a Terminal to the Console PortIn-Band Connections Remote Management via the Console PortConnecting the Power Cord Powering the SwitchNetwork Cable Requirements CopperFiber 10Base-T/100Base-TX Ports Base-LX Fiber SpecificationsFiber Uplink Modules 100Base-FX/1000Base-SX/LX Fiber PortsGeneral Appendix A. Technical SpecificationsPhysical Specifications Electrical SpecificationsConsole Port Port Specifications10Base-T and 100Base-TX Ports Table A-1. RS-232 Console Port Pin AssignmentsPower Cord Set Requirements MDI/MDI-X Crossover Cable WiringGeneral Requirements Country-Specific Requirements Table A-3. Power Cord Set Requirements by CountryTechnical Specifications VH-4802 Appendix B. Flow Control Flow Control VH-4802 Term Definition Appendix C. Acronyms & AbbreviationsSnmp Index Index VH-4802 9033520 Index Index VH-4802 Page 150420-102 R01