Asante Technologies 35516 user manual Forward Time, Hello Time, Maximum Age, Priority

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but where there is only one path between any two points (the connections span the entire network, and the paths are branched, like a tree).

All of the bridges (a switch is a complex bridge) on the network communicate with each other using special packets of data called Bridge Protocol Data Units (BPDUs). The information exchanged in the BPDUs allows the bridges on the network to do the following:

Elect a single bridge to be the root bridge

Calculate the shortest path from each bridge to the root bridge

Select a designated bridge on each segment, which lies closest to the root and forwards all traffic to it

Select a port on each bridge to forward traffic to the root

Select the ports on each bridge that forward traffic, and place the redundant ports in blocking states

Spanning Tree Parameters

The operation of the spanning tree algorithm is governed by several parameters. You can configure the following parameters from global configuration mode: forward-time, hello-time, max-age, and priority.

Router(config)#

spanning-tree ?

forward-time

Set forwarding delay time

hello-time

Set interval between HELLOs

max-age

Maximum allowed message age of received Hello BPDUs

priority

Set bridge priority

<cr>

 

Router(config)# spanning-tree

Forward Time

After a recalculation of the spanning tree, the Forward Time parameter regulates the delay before each port begins transmitting traffic. If a port begins forwarding traffic too soon (before a new root bridge has been selected), the network can be adversely affected. The default value for Forward Time is 15 seconds.

Hello Time

This is the time period between BPDUs transmitted by each bridge. The default setting is 2 seconds.

Maximum Age

Each bridge should receive regular configuration BPDUs from the direction of the root bridge. If the maximum age timer expires before the bridge receives another BPDU, it assumes that a change in the topology has occurred, and it begins recalculating the spanning tree. The default setting for Maximum Age is 20 seconds.

Note: The above parameters (Hello Time, Maximum Age, and Forward Time) are constrained by the following formula:

(Hello Time + 1) <= Maximum Age <= 2 x (Forward Delay – 1)

Priority

Setting the bridge priority to a low value will increase the likelihood that the current bridge will become the root bridge. If the current bridge is located physically near the center of the network, decrease the Bridge Priority from its default value of 32768 to make it become the root bridge. If the current bridge is near the edge of the network, it is best to leave the value of the Bridge Priority at its default setting.

In general, reducing the values of these timers will make the spanning tree react faster when the topology changes, but may cause temporary loops as the tree stabilizes in its new configuration. Increasing the values of these timers will make the tree react more slowly to changes in topology, but will make an unintended reconfiguration less likely. All of the bridges on the network will use the values set by the root bridge. It is only necessary to reconfigure that bridge if changing the parameters.

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Contents IntraCore 35516 Series IntraCore 35516 Series Technical SupportTable of Contents Page Features IntroductionPackage Contents LEDsFront and Back Panel Descriptions GbicManagement and Configuration Console InterfaceSafety Overview Hardware Installation and SetupInstallation Overview Recommended Installation ToolsEnvironmental Requirements Installation into an Equipment RackPower Requirements Cooling and AirflowInstalling a Gbic Gigabit Interface ConvertersGbic Care and Handling Installing the Optional Emergency Power SupplyRemoving a Gbic System Information System up since 103443 Fri Feb 071 10/100/1000BaseT Ports Cabling Procedures Connecting PowerConnecting to the Network Connecting to a Console SetupGigabit Ethernet Ports Cabling Procedures User Access Verification Password Specifies an Unencrypted line password will follow Setting PasswordsUnencrypted cleartext line password Specifies a Hidden line password will followRouterconfig-if-veth1# Configuring an IP AddressSetting a Default IP Gateway Address Routerconfig# boot system flash bank1bank2 Restoring Factory DefaultsSystem Boot Parameters Access Each Command Mode Understanding the Command Line Interface CLIUser Top User Exec Mode Command Show ? PurposeCommand Purpose Privileged Top Privileged Exec ModeRouter enable Password Router# Command Exit end Ctrl-Z Purpose Global Configuration ModeCommand Purpose Router# configure terminal Interface Configuration Mode Router Configuration Mode Route-Map Configuration ModeAdvanced Features Supported within the Command Mode Command Help PurposeRouterconfig# routed rip Invalid input detected at marker Checking Command SyntaxRouterconfig# hostname ? Word This systems network name Routerconfig# route Ambiguous command. Routerconfig#Using Command-Line Editing Features and Shortcuts Using CLI Command HistoryUsing the No and Default Forms of Commands Routerconfig# router Command incomplete. Routerconfig#Router# confTab Router# configure Moving Around on the Command LineCompleting a Partial Command Name Keystrokes PurposeDeleting Entries Editing Command Lines that WrapRouter# co? configure copy Router# co Keystrokes Purpose Press the Delete or BackspaceTransposing Mistyped Characters Redisplaying the Current Command LineScrolling Down a Line or a Screen Controlling CapitalizationPassword Passwords and Privileges CommandsEnable Password Routerconfig-line# password AsanteService Password-Encryption Changing the Password Managing the System and Configuration FilesSetting the System Clock Managing the SystemTrace Packet Routes Enable the System LogDisplaying the Operating Configuration Test Connections with Ping TestsConfiguration to Nvram Managing Configuration FilesConfiguring from the Terminal Routerconfig# hostname newname Newnameconfig# endCopying Configuration Files to a Network Server Running-config Configuring Snmp and Spanning TreeConfiguring Snmp Support Startup-configRouterconfig# duplicate-ip detect Configuring Spanning Tree Protocol STPCreate or Modify Access Control for Snmp Community Disable the Snmp ProtocolMaximum Age Forward TimeHello Time PriorityPort Priority Routerconfig# mac-address-table aging-timeMAC Address Table Port Path CostAssign IP Addresses to Network Interfaces Configuring IPConfiguring IP Addressing Class Address or Range StatusCidr Prefix Class C Equivalent Host Addresses Command PurposeAssign Multiple IP Addresses to Network Interfaces Define a Static ARP Cache Establish Address ResolutionConfiguring IP Routing SecondaryConfiguring Static Routes Route Source Default DistanceAllow Unicast Updates for RIP Configuring RIPEnable RIP Neighbor ip-addressRedistribute Routing Information Command Purpose Route-map map-tagdeny permit sequenceSpecify a RIP Version Set Administrative Distance Set Metrics for Redistributed RoutesFiltering Routing Information Generate a Default RouteSuppress Routing Updates through an Interface Manage Authentication Keys Adjust TimersEnable or Disable Split-horizon Command Purpose Offset-list access-list-name in outConfiguring IP Multicast Routing Monitor and Maintain RIPPurpose Ip igmp query-interval 1-65535 seconds Configuring IgmpModifying the Igmp Host-Query Message Interval Changing the Igmp Version CommandConfiguring the Router as a Statically Connected Member SecondsConfiguring Dvmrp Nbr-timeout 35-8000 secondsDefault value 200 seconds Default value 180 secondsCommand Purpose Route-expire-time 20-4000 seconds Report-intervalUsing Access Lists Create a Standard Access ListCreate an Expanded Access List Destination address to match. e.gOperator equal to Creating an Access List with a NameApplying an Access List to an Interface Operator greater thenConfigure ABR Type Configuring OspfEnable Ospf Command Purpose Router ospf StepConfigure Ospf Network Type Configure CompatibilityConfigure Ospf Interface Parameters Configure Ospf Not So Stubby Area Nssa Configure Ospf for Non-broadcast NetworksConfigure Area Parameters Command Purpose Neighbor ip-address priority numberCreate Virtual Links Configure Route Summarization between Ospf AreasCommand Purpose Area area-idvirtual-link router-idhello Not-advertisedRefresh Timer Configuration Control Default MetricsConfigure Route Calculation Timers Redistribute Routes into OspfCommand Purpose Distance ospf external distance1 inter-area Change the Ospf Administrative DistancesPrevent Routes from being Advertised in Routing Updates Suppress Routes on an InterfaceRouter ip-address NameVrrp Configuration Virtual Router Redundancy Protocol VrrpMonitoring and Maintaining the Network Configuring Icmp Router Discovery Protocol IrdpEnable Irdp Processing Change Irdp ParametersShow ip prefix-list prefix-list-name Command Purpose Show arp interfaceShow access-lists access-list Show ip irdpVlan Configuration Creating or Modifying a VlanDeleting a Vlan Routerconfig# interface veth2 vlan Routerconfig-if-veth2#Routerconfig# no vlan Routerconfig# exit Router# show vlan Trunk Ieee 802.1Q Static AccessVlan Port Membership Modes Trunk allowed vlan add all except Command Purpose Routerconfig# vlan dot1q tag native3 Dot1q Tunnel Mode dot1q-tunnel Appendix A. Basic Troubleshooting Problem Possible SolutionsTechnical Support and Warranty Appendix B. SpecificationsPhysical Characteristics Standards ComplianceIntraCare Warranty Statement Appendix C. FCC Compliance and Warranty StatementsFCC Compliance Statement Important Safety Instructions Page Pin Number Signal Name Appendix D. Console Port Pin OutsAppendix E. Online Warranty Registration