user manual
Table Of Contents
- Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
- Contents
- Preface
- New and Changed Information for this Release
- Overview
- Configuring Ethernet Interfaces
- Information About Ethernet Interfaces
- Configuring Ethernet Interfaces
- Configuring the UDLD Mode
- Changing an Interface Port Mode
- Configuring Interface Speed
- Disabling Link Negotiation
- Configuring the CDP Characteristics
- Enabling or Disabling CDP
- Enabling the Error-Disabled Detection
- Enabling the Error-Disabled Recovery
- Configuring the Error-Disabled Recovery Interval
- Configuring the Debounce Timer
- Configuring the Description Parameter
- Disabling and Restarting Ethernet Interfaces
- Displaying Interface Information
- Displaying Input Packet Discard Information
- Default Physical Ethernet Settings
- Configuring VLANs
- Configuring Private VLANs
- Information About Private VLANs
- Guidelines and Limitations for Private VLANs
- Configuring a Private VLAN
- Enabling Private VLANs
- Configuring a VLAN as a Private VLAN
- Associating Secondary VLANs with a Primary Private VLAN
- Configuring an Interface as a Private VLAN Host Port
- Configuring an Interface as a Private VLAN Promiscuous Port
- Configuring a Promiscuous Trunk Port
- Configuring an Isolated Trunk Port
- Configuring the Allowed VLANs for PVLAN Trunking Ports
- Configuring Native 802.1Q VLANs on Private VLANs
- Verifying the Private VLAN Configuration
- Configuring Access and Trunk Interfaces
- Configuring Switching Modes
- Configuring Rapid PVST+
- Information About Rapid PVST+
- Understanding STP
- Understanding Rapid PVST+
- Rapid PVST+ and IEEE 802.1Q Trunks
- Rapid PVST+ Interoperation with Legacy 802.1D STP
- Rapid PVST+ Interoperation with 802.1s MST
- Configuring Rapid PVST+
- Enabling Rapid PVST+
- Enabling Rapid PVST+ per VLAN
- Configuring the Root Bridge ID
- Configuring a Secondary Root Bridge
- Configuring the Rapid PVST+ Port Priority
- Configuring the Rapid PVST+ Pathcost Method and Port Cost
- Configuring the Rapid PVST+ Bridge Priority of a VLAN
- Configuring the Rapid PVST+ Hello Time for a VLAN
- Configuring the Rapid PVST+ Forward Delay Time for a VLAN
- Configuring the Rapid PVST+ Maximum Age Time for a VLAN
- Specifying the Link Type
- Restarting the Protocol
- Verifying Rapid PVST+ Configurations
- Information About Rapid PVST+
- Configuring Multiple Spanning Tree
- Information About MST
- Configuring MST
- MST Configuration Guidelines
- Enabling MST
- Entering MST Configuration Mode
- Specifying the MST Name
- Specifying the MST Configuration Revision Number
- Specifying the Configuration on an MST Region
- Mapping and Unmapping VLANs to MST Instances
- Mapping Secondary VLANs to Same MSTI as Primary VLANs for Private VLANs
- Configuring the Root Bridge
- Configuring a Secondary Root Bridge
- Configuring the Port Priority
- Configuring the Port Cost
- Configuring the Switch Priority
- Configuring the Hello Time
- Configuring the Forwarding-Delay Time
- Configuring the Maximum-Aging Time
- Configuring the Maximum-Hop Count
- Configuring PVST Simulation Globally
- Configuring PVST Simulation Per Port
- Specifying the Link Type
- Restarting the Protocol
- Verifying MST Configurations
- Configuring STP Extensions
- About STP Extensions
- Information About STP Extensions
- Configuring STP Extensions
- STP Extensions Configuration Guidelines
- Configuring Spanning Tree Port Types Globally
- Configuring Spanning Tree Edge Ports on Specified Interfaces
- Configuring Spanning Tree Network Ports on Specified Interfaces
- Enabling BPDU Guard Globally
- Enabling BPDU Guard on Specified Interfaces
- Enabling BPDU Filtering Globally
- Enabling BPDU Filtering on Specified Interfaces
- Enabling Loop Guard Globally
- Enabling Loop Guard or Root Guard on Specified Interfaces
- Verifying STP Extension Configuration
- About STP Extensions
- Configuring LLDP
- Configuring the MAC Address Table
- Configuring IGMP Snooping
- Configuring Traffic Storm Control
- INDEX

enabled, the interface status displays as err-disabled. Once an interface goes into the err-disabled state, you
must manually reenable it or you can configure an automatic timeout recovery value. The err-disabled detection
is enabled by default for all causes. The automatic recovery is not configured by default.
When an interface is in the err-disabled state, use the errdisable detect cause command to find information
about the error.
You can configure the automatic err-disabled recovery timeout for a particular err-disabled cause by changing
the time variable.
The errdisable recovery cause command provides automatic recovery after 300 seconds. To change the
recovery period, use the errdisable recovery interval command to specify the timeout period. You can specify
30 to 65535 seconds.
If you do not enable the err-disabled recovery for the cause, the interface stays in the err-disabled state until
you enter the shutdown and no shutdown commands. If the recovery is enabled for a cause, the interface is
brought out of the err-disabled state and allowed to retry operation once all the causes have timed out. Use
the show interface status err-disabled command to display the reason behind the error.
About Port Profiles
The Cisco Nexus 3000 Series device does not support Port Profiles.
Guidelines and Limitations for Port Profiles
The Cisco Nexus 3000 Series device does not support Port Profiles.
About the Debounce Timer Parameters
The debounce timer feature is not supported on Nexus 3000.
About MTU Configuration
The Cisco Nexus 3000 Series switch does not fragment frames. As a result, the switch cannot have two ports
in the same Layer 2 domain with different maximum transmission units (MTUs). A per-physical Ethernet
interface MTU is not supported. Instead, the MTU is set according to the QoS classes. You modify the MTU
by setting Class and Policy maps.
When you show the interface settings, a default MTU of 1500 is displayed for physical Ethernet interfaces.Note
Configuring Ethernet Interfaces
The section includes the following topics:
Cisco Nexus 3000 NX-OS Layer 2 Switching Configuration Guide, Release 5.0(3)U3(1)
OL-26590-01 11
Configuring Ethernet Interfaces
About Port Profiles