Configuring VLANs | Cisco Systems N3KC3064TFAL3, N3KC3048TP1GE

C H A P T E R 4

Configuring VLANs

This chapter contains the following sections:

•Information About VLANs, page 27

•Configuring a VLAN, page 30

Information About VLANs

Understanding VLANs

A VLAN is a group of end stations in a switched network that is logically segmented by function or application, without regard to the physical locations of the users. VLANs have the same attributes as physical LANs, but you can group end stations even if they are not physically located on the same LAN segment.

Any switch port can belong to a VLAN, and unicast, broadcast, and multicast packets are forwarded and flooded only to end stations in that VLAN. Each VLAN is considered as a logical network, and packets destined for stations that do not belong to the VLAN must be forwarded through a router. The following figure shows VLANs as logical networks. The stations in the engineering department are assigned to one VLAN,

Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)

OL-26590-01

27

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Cisco Systems N3KC3064TFAL3, N3KC3048TP1GE manual Configuring VLANs, Information About VLANs, Understanding VLANs

Contents

First Published February 29 Last Modified March 22 Americas HeadquartersPage N T E N T S Configuring VLANs Configuring Private VLANs Configuring Rapid PVST+ Configuring Multiple Spanning Tree Configuring the Port Priority Configuring Lldp Configuring Igmp Snooping Audience PrefaceDocument Conventions Convention Description Italic screen font Configuration Guides Installation and Upgrade GuidesError and System Messages Release Notes Obtaining Documentation and Submitting a Service Request Switching mode. There are two switching Feature Description Added orNew and Changed Information for this Release Changed Release OL-26590-01 Overview Layer 2 Ethernet Switching OverviewVLANs This chapter contains the following sections STP Overview Private VLANsSpanning Tree STP Extensions Rapid PVST+ Overview STP Extensions Information About Ethernet Interfaces Configuring Ethernet InterfacesAbout the Interface Command About the Unidirectional Link Detection Parameter Following table shows the default Udld configuration Default Udld ConfigurationFeature Udld Aggressive and Nonaggressive Modes Default CDP Configuration About the Error-Disabled StateFollowing table shows the default CDP configuration About Interface Speed About the Debounce Timer Parameters Configuring Ethernet InterfacesAbout MTU Configuration About Port Profiles Command or Action Purpose Step Configuring the Udld ModeSwitch# configure terminal Aggressive Command or Action Changing an Interface Port ModeRunning-config bootflash Running-config startup-config Transceiver inserted into it Configuring Interface SpeedSlot /port Disabling Link Negotiation Command or Action Purpose Advertise v1 Configuring the CDP CharacteristicsDevice-id mac-address Serial-number system-name Seconds Enabling or Disabling CDP Example Enabling the Error-Disabled Detection Configuring the Error-Disabled Recovery Interval Enabling the Error-Disabled RecoveryConfig t Enters configuration mode Copy running-config startup-config Configuring the Description Parameter Configuring the Debounce TimerErrdisable recovery interval interval Show interface status err-disabled Disabling and Restarting Ethernet Interfaces Switchconfig-if# shutdown Disables the interfaceDisplaying Interface Information Command Purpose Displaying Input Packet Discard Information Following example shows how to display the CDP neighbors Parameter Default Setting Default Physical Ethernet SettingsPage OL-26590-01 Understanding VLANs Configuring VLANsInformation About VLANs VLANs as Logically Defined Networks Vlan Ranges VLANs Numbers Range Usage Creating, Deleting, and Modifying VLANs About the Vlan Trunking Protocol Configuring a VlanCreating and Deleting a Vlan Guidelines and Limitations for VTP Vlan vlan-id vlan-range Configuring a VlanVlan-id vlan-range Active suspend Switchconfig# interface ethernetAdding Ports to a Vlan Switchconfig-if# switchport access vlan Configuring a Vlan as a Routed SVIConfigure terminal Enters global configuration mode Feature interface-vlan Enables the creation of SVIs You can configure routing protocols on this interface Configuring a Vlan as a Management SVIConfiguring VTP Show vtp password Vtp passwordCopy running-config Startup-config Switch# show running-config vlan vlanid vlanrange Verifying Vlan ConfigurationSwitch# show vlan brief id vlanid vlanrange name name Summary Information About Private VLANs Configuring Private VLANs Three types of Pvlan ports are as follows Primary and Secondary VLANs in Private VLANsPrivate Vlan Ports Primary, Isolated, and Community Private VLANs Private Vlan Traffic Flows Associating Primary and Secondary VLANs Private Vlan Isolated Trunks Private Vlan Promiscuous TrunksBroadcast Traffic in Private VLANs Private Vlan Port Isolation Switchconfig# feature private-vlan Configuring a Private VlanGuidelines and Limitations for Private VLANs Enabling Private VLANs Community isolated primary Configuring a Vlan as a Private VlanAssociating Secondary VLANs with a Primary Private Vlan Association Association add secondary-vlan-listRemove secondary-vlan-list Configuring an Interface as a Private Vlan Promiscuous Port Configuring an Interface as a Private Vlan Host Port Configuring the Allowed VLANs for Pvlan Trunking Ports Configuring a Promiscuous Trunk PortConfiguring an Isolated Trunk Port Configuring Native 802.1Q VLANs on Private VLANs Verifying the Private Vlan ConfigurationSwitch# show feature Switch# show interface switchport OL-26590-01 Understanding Access and Trunk Interfaces Configuring Access and Trunk InterfacesInformation About Access and Trunk Interfaces Devices in a Trunking Environment Understanding Ieee 802.1Q Encapsulation Header without and with 802.1Q Tag Included Understanding Access VLANs Understanding Native 802.1Q VLANs Understanding the Native Vlan ID for Trunk PortsUnderstanding Allowed VLANs Configuring a LAN Interface as an Ethernet Access Port Configuring Access and Trunk Interfaces Configuring Trunk Ports Configuring Access Host PortsSwitchconfig-if# switchport host On bpdu filtering and bpdu guard Configuring the Allowed VLANs for Trunking Ports Configuring the Native Vlan for 802.1Q Trunking PortsSpecified trunk, use the switchport trunk allowed vlan Port-channel number Switch# configure terminal Enters configuration mode Configuring Native 802.1Q VLANs Switchconfig# no vlan dot1q tag Verifying Interface ConfigurationSwitch# show vlan dot1q tag native Switch# show interface OL-26590-01 Information About Switching Modes Configuring Switching ModesCut-Through Switching Mode Store-and-Forward Switching Mode Licensing Requirements for Switching Modes Guidelines and Limitations for Switching ModesCut-Through Switching Mode Guidelines and Limitations Store-and-Forward Switching Mode Guidelines and Limitations Configuring Switching Modes Default Settings for Switching ModesEnabling Store-and-Forward Switching Reenabling Cut-Through Switching Saves the change persistently through reboots Feature History for Switching ModesThis example shows how to reenable cut-through switching Feature Name Releases Information Information About Rapid PVST+ Configuring Rapid PVST+Understanding STP STP Overview Understanding the Bridge ID Understanding How a Topology is Created Bridge Priority Value Bit extended system ID field is part of the bridge IDBit 8192 4096 2048 1024 512 256 128 Understanding BPDUs Creating the Spanning Tree Topology Election of the Root Bridge Rapid PVST+ Overview Understanding Rapid PVST+ Rapid PVST+ Flag Byte in Bpdu Rapid PVST+ BPDUs Proposal and Agreement Handshaking for Rapid Convergence Proposal and Agreement Handshake Variable Description Protocol TimersPort Roles Rapid PVST+ Port State Overview Port States Blocking State Synchronization of Port Roles Enabled Blocking Learning Yes Forwarding DisabledOperational Status Port State Topology? Processing Superior Bpdu Information Port Cost Spanning-Tree Dispute Mechanism Rapid PVST+ Interoperation with Legacy 802.1D STP Rapid PVST+ and Ieee 802.1Q TrunksPort Priority Bandwidth Enabling Rapid PVST+ Configuring Rapid PVST+Rapid PVST+ Interoperation with 802.1s MST Switch# configure Mode rapid-pvstEnabling Rapid PVST+ per Vlan Terminal Configuring the Root Bridge ID Spanning-tree mst max-ageconfiguration commands Configuring a Secondary Root Bridge Vlan vlan-list port-priority priority Configuring the Rapid PVST+ Port Priority Configuring the Rapid PVST+ Bridge Priority of a Vlan Configuring the Rapid PVST+ Pathcost Method and Port CostPathcost method long short Vlan vlan-id cost value auto Vlan-range hello-time hello-time Configuring the Rapid PVST+ Hello Time for a VlanSwitchconfig# spanning-tree vlan Configuring the Rapid PVST+ Maximum Age Time for a Vlan Configuring the Rapid PVST+ Forward Delay Time for a VlanSpecifying the Link Type Vlan-range forward-time forward-time Switch# clear spanning-tree detected-protocol Verifying Rapid PVST+ ConfigurationsSwitch# show running-config spanning-tree all Restarting the Protocol This example shows how to display spanning tree status Switch# show spanning-tree optionsSpanning tree configuration OL-26590-01 MST Overview Configuring Multiple Spanning TreeInformation About MST MST BPDUs MST Regions IST, CIST, and CST Overview MST Configuration InformationIST, CIST, and CST Spanning Tree Operations Between MST Regions Spanning Tree Operation Within an MST Region MST Regions, Cist Regional Roots, and CST Root MST Terminology Boundary Ports Hop Count MST Boundary Ports Spanning-Tree Dispute Mechanism Interoperability with Ieee 802.1D Port Cost and Port Priority MST Configuration Guidelines Configuring MSTYou must enable MST Rapid PVST+ is the default Enabling MST Switchconfig# spanning-tree mode mst Entering MST Configuration ModeSwitchconfig# no spanning-tree mode mst Mst configuration Spanning-tree mst Switchconfig# spanning-tree mstSpecifying the MST Name Instance-id vlan vlan-range Specifying the MST Configuration Revision NumberSpecifying the Configuration on an MST Region Version Name Mapping and Unmapping VLANs to MST Instances Default MSTI, which is the CistThis example shows how to map Vlan 200 to Msti Synchronize Configuring the Root BridgeSame Msti and their associated primary Vlan For all private VLANs 104 Mst instance-id root Configuring the Port PrioritySwitchconfig# no spanning-tree Optional Configuring the Switch Priority Configuring the Port Cost Hello-time seconds Configuring the Hello TimeConfigures the hello time for all MST instances. The hello Switch is alive. For seconds, the range is from 1 to 10, Configuring the Forwarding-Delay TimeConfiguring the Maximum-Aging Time Configuring Pvst Simulation Globally Configuring the Maximum-Hop CountMst max-age seconds Max-hops hop-count Configuring Pvst Simulation Per Port Switchconfig-if#spanning-tree mst simulate pvst disable Restarts MST on entire switch or Verifying MST ConfigurationsCommand Specified interfaces About STP Extensions Configuring STP ExtensionsInformation About STP Extensions Understanding STP Port Types Understanding Bpdu Guard Understanding Bridge Assurance Default Enable Disable Enabled/Disabled Is disabledUnderstanding Bpdu Filtering Port returns to Understanding Root Guard Understanding Loop Guard Configuring Spanning Tree Port Types Globally Configuring STP ExtensionsSTP Extensions Configuration Guidelines Port type network default Port type edge default Switchconfig-if# spanning-tree Switchconfig# interface typePort type edge Edge ports. Edge ports immediately transition to Port type network Ports. If you enable Bridge Assurance, it automaticallyEnabling Bpdu Guard Globally Enabling Bpdu Guard on Specified Interfaces Enables Bpdu Filtering by default on all Switchconfig-if# no spanning-tree bpduguardEdge bpdufilter default Filtering is disabled by default Bpdufilter Bpdufilter enable disableEnabling Bpdu Filtering on Specified Interfaces Normal and network ports. By default, global Loop Loopguard defaultGuard is disabled Enabling Loop Guard Globally Guard loop root none Verifying STP Extension Configuration 126 Configuring Global Lldp Commands Configuring Lldp Optionalswitch# show lldp Displays Lldp configurations Ensure that the Lldp feature is enabled on the switchHoldtime reinit timer Transmit Configuring Interface Lldp Commands This example shows how to display Lldp counters This example shows how to display Lldp timer information Configuring MAC Addresses Configuring the MAC Address TableConfiguring a Static MAC Address Information About MAC Addresses Switchconfig-# no mac-address-table static Configuring the Aging Time for the MAC TableSwitch# configure terminal Enters global configuration mode Macaddress vlan vlan-id Switchconfig# clear mac-address-table dynamic Verifying the MAC Address ConfigurationSwitch# show mac-address-table aging-time Defined in the switch This example shows how to display the current aging time This example shows how to display the MAC address table Information About Igmp Snooping Configuring Igmp Snooping IGMPv1 and IGMPv2 Igmp Snooping Switch Igmp Forwarding IGMPv3Igmp Snooping Querier Parameter Description Configuring Igmp Snooping Parameters Snooping No ip igmp snooping mrouter vpc-peer-linkNo ip igmp snooping mrouter Snooping fast-leave Snooping explicit-trackingLast-member-query-interval Snooping querier IP-address 141 Verifying Igmp Snooping Configuration 142 Information About Traffic Storm Control Configuring Traffic Storm Control Broadcast Suppression Traffic Storm Guidelines and Limitations Switchconfig-if# storm-control broadcast Configuring Traffic Storm ControlConfigures traffic storm control for traffic On the interface. The default state is Default Traffic Storm Settings Traffic Storm Control Example ConfigurationVerifying Traffic Storm Control Configuration Parameters Default D E Mstp Cist root 93 CIST, described 91 CST 91 Rstp 68, 71, 75, 89 active topology 71 Bpdu VLANs Adding ports to Private Configuring