Asante Technologies 35160 user manual Flow Control, Auto-Negotiation

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7.3.2 Flow Control

With a link operating at a high data rate, a switch may experience occasional limitations in the buffer space used to store Ethernet frames before forwarding them. In this situation, if the sending station continues to send frames, the switch will have no option but to discard the frames. This may quickly lead to unacceptable delays in upper-level protocols.

In order to avoid unnecessarily dropping frames, a switch may implement Flow Control. Flow control is a feature that allows the switch to recognize when the buffer space is limited, and to send an Ethernet PAUSE frame to its link partner to cease transmission for a specified period. As with a full-duplex link, both ends of the link must understand flow control for the mechanism to operate properly.

7.3.3 Auto-Negotiation

As discussed previously, make sure that both ends of a link agree about the duplex and flow control settings to be used (as well as the speed of the connection). In even a mid-sized network, making sure that all the links agree on all these parameters would be too big a job if the network manager had to configure every connection manually.

To make configuration as automatic as possible, the IEEE has defined standards so that most connections can be automatically configured by the hardware, without manual intervention. Devices can agree on the speed, duplex mode, and flow control settings for each individual connection. The possible links states are ranked:

1000 Mbps/Full Duplex

1000 Mbps/Half Duplex

100 Mbps/Full Duplex

100 Mbps/Half Duplex

10 Mbps/Full Duplex

10 Mbps/Half Duplex

With auto-negotiation, the link partners will configure the link to operate at the highest speed and duplex state that both support.

Auto-negotiation is supported on IntraCore switches on all UTP ports.

Note: If an Ethernet device that is capable of auto-negotiation is connected to a port that has auto- negotiation turned off, the auto-negotiating device will default to half duplex mode. If the port that is not using auto-negotiation is set to full duplex, the link will have a duplex mismatch, and will be so slow that it may be unusable. If an Ethernet port has been configured to operate in full-duplex mode, configure the link partner to also operate in full-duplex. It is almost always better to let auto-negotiation take care of this.

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Contents IntraCore 35160 Series Quick Start Guide IntraCore 35160 Series Layer 2 Gigabit Switches User’s ManualTable of Contents Page Introduction FeaturesPackage Contents SwitchCore CXE2010LEDs 2 IC35160-G 1 IC35160-TFront and Back Panel Descriptions Management and ConfigurationWeb-Based Interface Console InterfaceSnmp Management Recommended Installation Tools Hardware Installation and SetupInstallation Overview Safety OverviewCooling and Airflow Installation into an Equipment RackPower Requirements Environmental RequirementsGbic Interfaces Installing a GbicGbic Care and Handling Installing the Optional Emergency Power SupplyConnecting Power Removing a Gbic1 10/100/1000BaseT Ports Cabling Procedures Connecting to the NetworkGigabit Ethernet Ports Cabling Procedures SetupConnecting to a Console Connecting Via Telnet Connecting Via the Web BrowserIP Assignment Changing the PasswordSimple Network Management Protocol Snmp Exiting a Submenu ConfigurationAccessing a Submenu LoggingGeneral Information Configuration MenuChanging System Administration Info Administration ConfigurationPort Configuration System IP ConfigurationChanging System IP Information Page Enabling or Disabling a Port Advanced Port ConfigurationEnabling or Disabling 802.3x Flow Control Setting Port Class of ServiceSetting Port Default Priority Setting Port Maximum Packet LengthGlobal Port Configuration Unicast Forwarding Database ConfigurationDisplaying the Forwarding Database Searching for a MAC Address Setting the MAC Address Age-Out TimeSecurity Management Vlan ManagementSnmp Configuration Protocol ConfigurationChanging Community Strings Adding or Updating a Trap Receiver Enabling Authentication TrapsDeleting a Trap Receiver Spanning Tree Protocol STP ConfigurationSetting Port Priority and Path Cost Spanning Tree Port ConfigurationEnabling and Disabling STP Trunk Group Configuration Defining the Priority List QoS Priority Queue ManagementAssigning Packets to Priority Queues Example Setting Console UI Time-out Period User Interface ConfigurationSetting SSH/Telnet UI Time-out Adding or Deleting an Access Host Change PasswordEnabling or Disabling SSH and Telnet System Utilities Access ControlEnabling or Disabling the Web Server Enabling or Disabling System Port Mirroring Port MirroringAdding or Deleting a Monitor Port Resetting the Switch System ResetSystem Clock System Log Scheduling a System ResetClearing the System Log Bootstrap ConfigurationTftp File Transfers Ping Utility StatisticsSnmp and Rmon Management Advanced ManagementRmon Management Viewing a List of Duplicated IP Addresses Duplicated IP Detection and TrapEnabling and Disabling Duplicated IP Detection Enabling and Disabling Duplicated IP TrapEnabling and Disabling Station Movement Trap Configuring Port SecurityConfiguring Port Lock and Intruder Lock Configuring Port New Node Detection TrapResetting Security to Defaults Port-based Network Access ControlConfiguring Security Level 2 or Level Setting the Intruder TrapPage Name Description Port Control SettingsSetting Timers Radius Server IP Setting Radius ParametersServer Port Other Vlan Features of the switch Vlan Specifications for the IntraCore 35160 SeriesVlan Management Creating a Vlan Configuring Static Vlan GroupsAdvanced Static Vlan Configuration Adding and Deleting VLANs from the Port Configuring Vlan Port AttributesSetting the Port Vlan ID Configuring Port Receive Frame TypeDisplaying a Summary of Vlan Groups Setting Port TypeMulticast Addresses Resetting Vlan Configuration to DefaultsIP Multicast Traffic Management Displaying a Vlan Port SummaryIgmp Snooping Configuring IP Multicast Traffic ManagementEnabling and Disabling Igmp Snooping Displaying a Summary of Group Addresses Advanced Igmp ConfigurationRemoving a Multicast Group Address IP Multicast Forwarding Database ConfigurationAdding Ports to the Selected Address Inserting a Multicast Group AddressWeb-Based Management Accessing with a Web BrowserGenl Info General Information Button Front Panel ButtonManagement Buttons Port Config Port Configuration Button Span Tree Spanning Tree Button Addr Address Table Button Snmp ButtonVlan Button Vlan ConfigurationVlan Group Create Acceptable Frame Type Port ConfigurationSet Port Type Port Vlan ID PvidTag/Untag Port Egress Type Trunking ButtonSecurity Button Port Ingress FilteringPage Snmp Management Operations Snmp ManagementSnmp Protocol MIB Tree Community Name and SecurityName Space Path MIB Groups Supported Vlan ID and Tagged Frames Switching ConceptsVLANs Port-Based VLANsSpanning Tree Parameters Spanning Tree ProtocolPort Vlan ID How It WorksFull Duplex, Flow Control, and Auto-negotiation Spanning Tree Port ConfigurationFull Duplex Auto-Negotiation Flow ControlProblem Possible Solutions Appendix A. TroubleshootingSpecifications Appendix B. Features and SpecificationsPhysical Characteristics Environmental Range Technical Support and WarrantyStandards Compliance FCC Compliance Statement Important Safety Instructions Appendix C. FCC Compliance and Warranty StatementsIntraCare Warranty Statement Page Appendix D. Console Port Pin Outs Pin Number Signal NameAppendix E. Online Warranty Registration Loading Software Locally Appendix F. BootP ConfigurationBootstrap Configuration Image BanksLoading Software Remotely BOOTP-TFTP