Glossary | 3Com 3 specification

92GLOSSARY

Fast Ethernet is 100 Mbps, and the bandwidth of Gigabit Ethernet is 1000 Mbps.

baud The signalling rate of a line, that is, the number of transitions (voltage or frequency changes) made per second. Also known as line speed.

BOOTP The BOOTP protocol allows you to automatically map an IP address to a given MAC address each time a device is started. In addition, the protocol can assign the subnet mask and default gateway to a device.

bridge A device that interconnects two LANs of a different type to form a single logical network that comprises of two network segments.

Bridges learn which endstations are on which network segment by examining the source addresses of packets. They then use this information to forward packets based on their destination address. This process is known as filtering.

broadcast A packet sent to all devices on a network.

broadcast storm Multiple simultaneous broadcasts that typically absorb all the available network bandwidth and can cause a network to fail. Broadcast storms can be due to faulty network devices.

cache Stores copies of frequently accessed objects locally to users and serves them to users when requested.

Classifier Classifies the traffic on the network. Traffic classifications are determined by protocol, application, source, destination, and so on. You can create and modify classifications. The Switch then groups classified traffic in order to schedule them with the appropriate service level.

collision A term used to describe two colliding packets in an Ethernet network. Collisions are a part of normal Ethernet operation, but a sudden prolonged increase in the number of collisions can indicate a problem with a device, particularly if it is not accompanied by a general increase in traffic.

CSMA/CD Carrier-sense Multiple Access with Collision Detection. The protocol defined in Ethernet and IEEE 802.3 standards in which devices transmit only after finding a data channel clear for a period of time. When two devices transmit simultaneously, a collision occurs and the colliding devices delay their retransmissions for a random length of time.

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3Com 3 manual Glossary

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 Related DocumentationComments Pddtechpubscomments@3com.com Product Registration Switch Features Page What is Switch FeaturesManagement Software? Switch Features Overview Ports operating at 1000 Mbps only support full duplex mode For more information about multicast filtering, see UsingDuplex Flow Control For more information about STP and RSTP, see Using Resilience Features Event Notification Quality of ServiceFor more information about Quality of Service, see Using 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 Query modeSnooping Mode Igmp v2 protocol That support IPIgmp multicast filtering works as follows Enabling Igmp Multicast Learning Igmp Multicast Filtering Using Multicast Filtering Network Spanning TreeProtocol STP 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 3 Redundancy for Cabling Error Configuration 1 Redundancy for Backbone LinkConfiguration 2 Redundancy through Meshed Backbone STP configurations Default Behavior Using STP on aNetwork with Multiple VLANs Configuration that separates VLANs Using Resilience Features What is the Switch How SwitchDatabase? Database Entries Switch Database Entry States Databases entries can have three states What is Traffic Prioritization?Available 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 That allows you to monitor the traffic of LANs or VLANs What is RMON?Network efficiency and reduce the load on your network It improves your efficiency AlarmsEvents 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 Configuration Using UntaggedConfigure the VLANs Examples Add ports to the VLANs Configure the VLANs on SwitchAdd endstation ports on Switch 1 to the VLANs Add port 12 on Switch 1 to the VLANs Add endstation ports on Switch 2 to the VLANsAdd port 11 on Switch 2 to the VLANs Check the Vlan membership for both switches Configuration How Your Switch Obtains IPInformation How Automatic IP How Automatic IP Configuration Works Considerations Automatic IP configuration featureThat a Switch may change its IP address whilst in use Configuration Rules IP AddressingGlossary 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 Segments are connected to the Switch which is positioned Simple NetworkFamily and 4900 family can be used in your network Example Dual Speed Hub Switch Advanced Network ImprovingResilience of Your Network Therefore the overall network performance EnhancingPerformance IP Addresses Simple Overview Obtaining a Registered IP Address IP Address Network Portion Dotted Decimal NotationDecimal value of an octet whose bits are all 1s is Subnet mask Subnet Mask Numbering Extending the Network Prefix Or leave the field blank Glossary Glossary Endstation EthernetEthernet address Fast Ethernet Gateway Half duplexHub 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