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Cisco Nexus 7000 Series NX-OS Interfaces Configuration Guide, Release 4.x
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Index
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New and Changed Information for Interfaces NX-OS Configuration Guide
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Preface
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Overview
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Configuring Basic Interface Parameters
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Configuring Access and Trunk Interfaces
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Configuring Layer 3 Interfaces
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Configuring Port Channels
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Configuring vPCs
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Configuring IP Tunnels
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IETF RFCs Supported by Cisco NX-OS Interfaces
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Configuration Limits for Cisco NX-OS Interfaces
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Feedback
Table Of Contents
Configuring Basic Interface Parameters
Information About the Basic Interface Parameters
Unidirectional Link Detection Parameter
UDLD Aggressive and Nonaggressive Modes
Configuring the Basic Interface Parameters
Specifying the Interfaces to Configure
Changing the Bandwidth-Rate Mode
Dedicating Bandwidth to One Port
Sharing the Bandwidth Among a Port Group
Configuring the Error-Disabled State
Enabling the Error Disable Detection
Enabling the Error-Disabled Recovery
Configuring the Error-Disabled Recovery Interval
Configuring the MDIX Parameter
Configuring the Debounce Timer
Configuring the Interface Speed and Duplex Mode
Configuring the Interface MTU Size
Configuring the System Jumbo MTU Size
Configuring the Throughput Delay
Shutting Down and Activating the Interface
Configuring the Carrier Delay Timer
Entering Port-Profile Configuration Mode and Modifying a Port Profile
Assigning a Port Profile to a Range of Interfaces
Enabling a Specific Port Profile
Removing a Port Profile from a Range of Interfaces
Removing an Inherited Port Profile
Verifying the Basic Interface Parameters
Displaying and Clearing the Interface Counters
Displaying Interface Statistics
Feature History for Configuring Basic Interface Parameters
Configuring Basic Interface Parameters
This chapter describes how to configure the basic interface parameters on the Cisco Nexus 7000 Series NX-OS devices.
This chapter includes the following sections:
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Information About the Basic Interface Parameters
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Note
Information About the Basic Interface Parameters
This section includes the following topics:
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Description
For the Ethernet and management interfaces, you can configure the description parameter to provide a recognizable name for the interface. Using a unique name for each interface allows you to quickly identify the interface when you are looking at a listing of multiple interfaces.
For information on setting the description parameter for port-channel interfaces, see the "Configuring a Port-Channel Description" section. For information on configuring this parameter for other interfaces, see the "Configuring the Description" section.
Beacon
The beacon mode allows you to identify a physical port by flashing its link state LED with a green light. By default, this mode is disabled. To identify the physical port for an interface, you can activate the beacon parameter for the interface.
For information on configuring the beacon parameter, see the "Configuring the Beacon Mode" section.
MDIX
The medium dependent interface crossover (MDIX) parameter enables or disables the detection of a crossover connection between devices. This parameter applies only to copper interfaces. By default, this parameter is enabled.
For information on configuring the MDIX parameter, see the "Configuring the MDIX Parameter" section.
Debounce Timer
The debounce timer delays notification of a link change, which can decrease traffic loss due to network reconfiguration. You can configure the debounce timer separately for each Ethernet port and specify the delay time in milliseconds. By default, this parameter is set for 100 milliseconds.
Caution
For information on configuring the debounce-timer parameters, see the "Configuring the Debounce Timer" section.
Error Disabled
A port is in the error-disabled (err-disabled) state when the port is enabled administratively (using the no shutdown command) but disabled at runtime by any process. For example, if UDLD detects a unidirectional link, the port is shut down at runtime. However, because the port is administratively enabled, the port status displays as err-disable. Once a port goes into the err-disable state, you must manually reenable it or you can configure a timeout value that provides an automatic recovery. By default, the automatic recovery is not configured, and by default the err-disable detection is enabled for all causes.
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 error-disabled recovery timeout for a particular error-disabled cause and configure the recovery period.
The errdisable recovery cause command provides an automatic recovery after 300 seconds.
You can use the errdisable recovery interval command to change the recovery period within a range of 30 to 65535 seconds. You can also configure the recovery timeout for a particular err-disable cause
If you do not enable the error-disabled recovery for the cause, the interface stays in the error-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 error-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.
Rate Mode
On a 32-port 10-Gigabit Ethernet module, each set of four ports can handle 10 gigabits per second (Gb/s) of bandwidth. You can use the rate-mode parameter to dedicate that bandwidth to the first port in the set of four ports or share the bandwidth across all four ports.
Table 2-1 identifies the ports that are grouped together to share each 10 Gb/s of bandwidth and which port in the group can be dedicated to utilize the entire bandwidth.
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Speed Mode and Duplex Mode
The speed mode and duplex mode are interrelated for each Ethernet and management interface. By default, each of these interfaces autonegotiates its speed and duplex mode with the other interface, but you can change these settings. If you change the settings, be sure to use the same speed and duplex mode setting on both interfaces, or use autonegotiation for at least one of the interfaces. Table 2-2 shows the settings that work for each type of Ethernet and management interface.
Table 2-2 Speed- and Duplex-Mode Settings Used for Ethernet and Management Interfaces
32-port 10-Gigabit Ethernet
Auto1
Auto1
10,000
Full
48-port 10/100/1000 Ethernet
Auto1
Auto1
1000
Full
10 or 100
Half
1000
Auto1 or full
1000
Full
100
Auto1 or half
100
Half
Full
100
Full
10
Auto1 or half
10
Half
Full
10
Full
Management
Auto1
Auto1
1000
Full
10 or 100
Half
1000
Auto1 or full
1000
Full
100
Auto1 or half
100
Half
Full
100
Full
10
Auto1 or half
10
Half
Full
10
Full
1 Default setting
For information on setting the speed mode and duplex mode for port-channel interfaces, see the "Configuring the Speed and Duplex Settings for a Port-Channel Interface" section. For information on setting the speed and duplex speed for other interfaces, see the "Configuring the Interface Speed and Duplex Mode" section.
Flow Control
When the receive buffer for an Ethernet port that runs 1 Gb/s or faster fills, flow control enables that port to send an IEEE 802.3x pause frame to the transmitting port to request it to stop transmitting data for a specified amount of time. Transmitting ports, running at any speed, can receive the pause frames to stop their transmission of data.
To allow flow control to work between two ports, you must set the corresponding receive and send flow control parameters for both ports as enabled or desired. When you set the parameter to enabled, the send or receive flow-control function is activated regardless of the setting of the other port. When you set the parameter to desired, the send or receive flow-control function is activated if you set the corresponding flow-control state of the other port to enabled or desired. If you set one of the flow control states to disabled, flow control is disabled for that transmission direction. To see how the different port flow-control states affect the link flow-control state, see Table 2-3.
For information on setting the flow-control parameters, see the "Configuring the Flow Control" section.
Port MTU Size
The maximum transmission unit (MTU) size specifies the maximum frame size that an Ethernet port can process. For transmissions to occur between two ports, you must configure the same MTU size for both ports. A port drops any frames that exceed its MTU size.
By default, each port has an MTU of 1500 bytes, which is the IEEE 802.3 standard for Ethernet frames. Larger MTU sizes are possible for more efficient processing of data with less overhead. The larger frames, called jumbo frames, can be up to 9216 bytes in size, which is also the default system jumbo MTU size.
On a Layer 3 interface, you can configure an MTU size between 576 and 9216 bytes. You can configure up to 64 MTU settings for each I/O module.
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For a Layer 2 port, you can configure an MTU size that is either the system default (1500 bytes) or the system jumbo MTU size (initially 9216 bytes).
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For information on setting the MTU size, see the "Configuring the MTU Size" section.
Bandwidth
Ethernet ports have a fixed bandwidth of 1,000,000 Kb at the physical level. Layer 3 protocols use a bandwidth value that you can set for calculating their internal metrics. The value that you set is used for informational purposes only by the Layer 3 protocols—it does not change the fixed bandwidth at the physical level. For example, the Interior Gateway Routing Protocol (IGRP) uses the minimum path bandwidth to determine a routing metric, but the bandwidth at the physical level remains at 1,000,000 Kb.
For information on configuring the bandwidth parameter for port-channel interfaces, see the "Configuring the Bandwidth and Delay for Informational Purposes" section. For information on configuring the bandwidth parameter for other interfaces, see the "Configuring the Bandwidth" section.
Throughput Delay
Specifying a value for the throughput-delay parameter provides a value used by Layer 3 protocols; it does not change the actual throughput delay of an interface. The Layer 3 protocols can use this value to make operating decisions. For example, EIGRP can use the delay setting to set a preference for one Ethernet link over another, if other parameters such as link speed are equal. The delay value that you set is in the tens of microseconds.
For information on configuring the bandwidth parameter for port-channel interfaces, see the "Configuring the Bandwidth and Delay for Informational Purposes" section. For information on configuring the throughput-delay parameter for other interfaces, see the "Configuring the Throughput Delay" section.
Administrative Status
The administrative-status parameter determines whether an interface is up or down. When an interface is administratively down, it is disabled and unable to transmit data. When an interface is administratively up, it is enabled and able to transmit data.
For information on configuring the administrative status parameter for port-channel interfaces, see the "Shutting Down and Restarting the Port-Channel Interface" section. For information on configuring the administrative-status parameter for other interfaces, see the "Shutting Down and Activating the Interface" section.
Unidirectional Link Detection Parameter
This section includes the following topics:
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UDLD Overview
The Cisco-proprietary Unidirectional Link Detection (UDLD) protocol allows devices that are connected through fiber-optic or copper (for example, Category 5 cabling) Ethernet cables to monitor the physical configuration of the cables and detect when a unidirectional link exists. When a device detects a unidirectional link, UDLD shuts down the affected LAN port and alerts the user. Unidirectional links can cause a variety of problems, including spanning tree topology loops.
UDLD is a Layer 2 protocol that works with the Layer 1 protocols to determine the physical status of a link. At Layer 1, autonegotiation takes care of physical signaling and fault detection. UDLD performs tasks that autonegotiation cannot perform, such as detecting the identities of neighbors and shutting down misconnected LAN ports. When you enable both autonegotiation and UDLD, Layer 1 and Layer 2 detections work together to prevent physical and logical unidirectional connections and the malfunctioning of other protocols.
A unidirectional link occurs whenever traffic transmitted by the local device over a link is received by the neighbor but traffic transmitted from the neighbor is not received by the local device. If one of the fiber strands in a pair is disconnected, as long as autonegotiation is active, the link does not stay up. In this case, the logical link is undetermined, and UDLD does not take any action. If both fibers are working normally at Layer 1, then UDLD at Layer 2 determines whether those fibers are connected correctly and whether traffic is flowing bidirectionally between the correct neighbors. This check cannot be performed by autonegotiation, because autonegotiation operates at Layer 1.
The Cisco Nexus 7000 Series device periodically transmits UDLD frames to neighbor devices on LAN ports with UDLD enabled. If the frames are echoed back within a specific time frame and they lack a specific acknowledgment (echo), the link is flagged as unidirectional and the LAN port is shut down. Devices on both ends of the link must support UDLD in order for the protocol to successfully identify and disable unidirectional links. You can configure the transmission interval for the UDLD frames, either globally or for the specified interfaces.
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Figure 2-1 shows an example of a unidirectional link condition. Device B successfully receives traffic from device A on the port. However, device A does not receive traffic from device B on the same port. UDLD detects the problem and disables the port.
Figure 2-1 Unidirectional Link
Default UDLD Configuration
Table 2-4 shows the default UDLD configuration.
For information on configuring the UDLD for the device and its port, see the "Configuring the UDLD Mode" section.
UDLD Aggressive and Nonaggressive Modes
UDLD aggressive mode is disabled by default. You can configure UDLD aggressive mode only on point-to-point links between network devices that support UDLD aggressive mode. If UDLD aggressive mode is enabled, when a port on a bidirectional link that has a UDLD neighbor relationship established stops receiving UDLD frame, UDLD tries to reestablish the connection with the neighbor. After eight failed retries, the port is disabled.
To prevent spanning tree loops, nonaggressive UDLD with the default interval of 15 seconds is fast enough to shut down a unidirectional link before a blocking port transitions to the forwarding state (with default spanning tree parameters).
When you enable the UDLD aggressive mode, the following occurs:
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In these cases, the UDLD aggressive mode disables one of the ports on the link, which prevents traffic from being discarded.
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Tip
To restore service after the ISSU has completed, run a shutdown followed by a no shutdown command on the local port.
Carrier Delay
Note
If a link goes down and comes back up before the carrier delay timer expires, the down state is effectively filtered, and the rest of the software on the device is not aware that a link-down event occurred. A large carrier delay timer results in fewer link-up/link-down events being detected. When you set the carrier delay time to 0, the device detects each link-up/link-down event that occurs.
In most environments, a lower carrier delay time is better than a higher one. The exact value that you choose depends on the nature of the link outages and how long you expect these linkages to last in your network. If your data links are subject to short outages (especially if those outages last less time than it takes for your IP routing to converge), you should set a long carrier delay value to prevent these short outages from causing unnecessary problems in your routing tables. However, if your outages tend to be longer, then you may want to set a shorter carrier delay time so that the outages are detected sooner, and the IP route convergence begins and ends sooner.
The default carrier-delay time is 2 seconds or 50 milliseconds.
Port-Channel Parameters
A port channel is an aggregation of physical interfaces that comprise a logical interface. You can bundle up to eight individual interfaces into a port channel to provide increased bandwidth and redundancy. Port channeling also load balances traffic across these physical interfaces. The port channel stays operational if at least one physical interface within the port channel is operational.
You can create a Layer 2 port channel by bundling compatible Layer 2 interfaces, or you can create Layer 3 port channels by bundling compatible Layer 3 interfaces. You cannot combine Layer 2 and Layer 3 interfaces in the same port channel.
Any configuration changes that you apply to the port channel are applied to each interface member of that port channel.
For information on port channels and for information on configuring port channels, see Chapter 5 "Configuring Port Channels."
Port Profiles
Beginning with Cisco NX-OS Release 4.2(1) for the Cisco Nexus 7000 Series devices, you can create a port profile that contains many interface commands and apply that port profile to a range of interfaces. Each port profile can be applied only to a specific type of interface; the choices are as follows:
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You inherit the port profile when you attach the port profile to an interface or range of interfaces, When you attach, or inherit, a port profile to an interface or range of interfaces, the system applies all the commands in that port profile to the interfaces. Additionally, you can have one port profile inherit the settings from another port profile. Inheriting another port profile allows the initial port profile to assume all of the commands of the second, inherited, port profile that do not conflict with the initial port profile. Four levels of inheritance are supported. The same port profile can be inherited by any number of port profiles.
The system applies the commands inherited by the interface or range of interfaces according to the following guidelines:
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A subset of commands are available under the port-profile configuration mode, depending on which interface type you specify.
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To apply the port-profile configurations to the interfaces, you must enable the specific port profile. You can configure and inherit a port profile onto a range of interfaces prior to enabling the port profile; you would then enable that port profile for the configurations to take effect on the specified interfaces.
If you inherit one or more port profiles onto an original port profile, only the last inherited port profile must be enabled; the system assumes that the underlying port profiles are enabled.
When you remove a port profile from a range of interfaces, the system undoes the configuration from the interfaces first and then removes the port-profile link itself. Also, when you remove a port profile, the system checks the interface configuration and either skips the port-profile commands that have been overridden by directly entered interface commands or returns the command to the default value.
If you want to delete a port profile that has been inherited by other port profiles, you must remove the inheritance before you can delete the port profile.
You can also choose a subset of interfaces from which to remove a port profile from among that group of interfaces that you originally applied the profile. For example, if you configured a port profile and configured ten interfaces to inherit that port profile, you can remove the port profile from just some of the specified ten interfaces. The port profile will continue to operate on the remaining interfaces to which it is applied.
If you delete a specific configuration for a specified range of interfaces using the interface configuration mode, that configuration is also deleted from the port profile for that range of interfaces only. For example, if you have a channel group inside a port profile and you are in the interface configuration mode and you delete that port channel, the specified port channel is also deleted from the port profile as well.
Just as in the device, you can enter a configuration for an object in port profiles without that object being applied to interfaces yet. For example, you can configure a virtual routing and forward instance (VRF) without it being applied to the system. If you then delete that VRF and attendant configurations from the port profile, the system is unaffected.
After you inherit a port profile on an interface or range of interfaces and you delete a specific configuration value, that port-profile configuration will not be operative on the specified interfaces.
If you attempt to apply a port profile to the wrong type of interface, the system returns an error.
When you attempt to enable, inherit, or modify a port profile, the system creates a checkpoint. If the port-profile configuration fails, the system rolls back to the prior configuration and returns an error. A port profile is never only partially applied.
Licensing Requirements
The following table shows the licensing requirements for this feature:
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Guidelines and Limitations
Follow these guidelines and limitations for configuring the basic interface parameters:
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By default, each port is a Layer 3 interface.
You can change a Layer 3 interface into a Layer 2 interface by using the switchport command. You can change a Layer 2 interface into a Layer 3 interface by using the no switchport command.
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Caution
Configuring the Basic Interface Parameters
When you configure an interface, you must specify the interface before you can configure its parameters.
The following sections explain how to specify the interface and configure each of its basic parameters:
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Specifying the Interfaces to Configure
Before you can configure the parameters for one or more interfaces of the same type, you must specify the type and the identities of the interfaces.
Table 2-5 shows the interface types and identities that you should use for specifying the Ethernet and management interfaces.
Table 2-5 Information Needed to Identify an Interface for Configurations
Ethernet
I/O module slot numbers and port numbers on the module.
Management
0 (for port 0)
The interface range configuration mode allows you to configure multiple interfaces with the same configuration parameters. After you enter the interface range configuration mode, all command parameters you enter are attributed to all interfaces within that range until you exit out of the interface range configuration mode.
You enter a range of interfaces using dashes (-) and commas (,). Dashes separate contiguous interfaces and commas separate noncontiguous interfaces. When you enter noncontiguous interfaces, you must enter the media type for each interface.
The following example shows how to configure a contiguous interface range:
switch(config)#interface ethernet 2/29-30switch(config-if-range)#The following example shows how to configure a noncontiguous interface range:
switch(config)#interface ethernet 2/29, ethernet 2/33, ethernet 2/35switch(config-if-range)#You can specify subinterfaces in a range only when the subinterfaces are on the same port, for example, 2/29.1-2. But you cannot specify the subinterfaces in a range of ports, for example, you cannot enter 2/29.2-2/30.2. You can specify two of the subinterfaces discretely, for example, you can enter 2/29.2, 2/30.2.
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Note
When you are in the interface configuration mode, the commands that you enter configure the interface that you specified for this mode.
Configuring the Description
You can provide textual interface descriptions for the Ethernet and management interfaces. Descriptions can be a maximum of 80 case-sensitive alphanumeric characters.
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This example shows how to set the interface description to Ethernet port 24 on module 3:
switch# config tswitch(config)# interface ethernet 3/24switch(config-if)# description server1switch(config-if)#Configuring the Beacon Mode
You can enable the beacon mode for an Ethernet port to flash its LED to confirm its physical location.
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This example shows how to enable the beacon mode for the Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# beaconswitch(config-if)#This example shows how to disable the beacon mode for the Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# no beaconswitch(config-if)#Changing the Bandwidth-Rate Mode
You can specify whether each 10 Gb of bandwidth on a 32-port 10-Gigabit Ethernet module is dedicated to one port or shared by four ports in the same port group.
This section includes the following topics:
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Dedicating Bandwidth to One Port
When you dedicate the bandwidth to one port, you must first administratively shut down the four ports in the group, change the rate mode to dedicated, and then bring the dedicated port administratively up.
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This example shows how to configure the dedicated mode for Ethernet port 4/17 in the group that includes ports 4/17, 4/19, 4/21, and 4/23:
switch# config tswitch(config)# interface ethernet 4/17, ethernet 4/19, ethernet 4/21, ethernet 4/23switch(config-if)# shutdownswitch(config-if)# interface ethernet 4/17switch(config-if)# rate-mode dedicatedswitch(config-if)# no shutdownswitch(config-if)#Sharing the Bandwidth Among a Port Group
You can share 10 Gb of bandwidth among a group of ports (four ports) on a 32-port 10-Gigabit Ethernet module. To share the bandwidth, you must bring the dedicated port administratively down, specify the ports that are to share the bandwidth, change the rate mode to shared, and then bring the ports administratively up.
BEFORE YOU BEGIN
All ports in the same group must belong to the same VDC.
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This example shows how to configure the shared mode for Ethernet port 4/17 in the group that includes ports 4/17, 4/19, 4/21, and 4/23:
switch# config tswitch(config)# interface ethernet 4/17switch(config-if)# shutdownswitch(config)# interface ethernet 4/17, ethernet 4/19, ethernet 4/21, ethernet 4/23switch(config-if)# rate-mode sharedswitch(config-if)# no shutdownswitch(config-if)#Configuring the Error-Disabled State
You can view the reason an interface moves to the error-disabled state and configure automatic recovery.
This section includes the following topics:
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Enabling the Error Disable Detection
You can enable error-disable detection in an application. As a result, when a cause is detected on an interface, the interface is placed in an error-disabled state, which is an operational state that is similar to the link-down state.
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This example shows how to enable the error-disabled detection in all cases:
switch(config)# errdisable detect cause all
switch(config)#
Enabling the Error-Disabled Recovery
You can specify the application to bring the interface out of the error-disabled state and retry coming up. It retries after 300 seconds, unless you configure the recovery timer (see the errdisable recovery interval command).
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This example shows how to enable error-disabled recovery under all conditions:
switch(config)# errdisable recovery cause all
switch(config)#
Configuring the Error-Disabled Recovery Interval
You can configure the error-disabled recovery timer value.
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This example shows how to configure the error-disabled recovery timer to set the interval for recovery to 32 seconds:
switch(config)# errdisable recovery interval 32switch(config)#Configuring the MDIX Parameter
If you need to detect the type of connection (crossover or straight) with another copper Ethernet port, enable the medium dependent independent crossover (MDIX) parameter for the local port. By default, this parameter is enabled.
BEFORE YOU BEGIN
You must enable MDIX for the remote port.
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This example shows how to enable MDIX for Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# mdix autoswitch(config-if)#
This example shows how to disable MDIX for Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# no mdixswitch(config-if)#Configuring the Debounce Timer
You can enable the debounce timer for Ethernet ports by specifying a debounce time, in milliseconds (ms), or disable the timer by specifying a debounce time of 0.
You can show the debounce times for all of the Ethernet ports by using the show interface debounce command.
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This example shows how to enable the debounce timer and set the debounce time to 1000 ms for the Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# link debounce time 1000switch(config-if)#This example shows how to disable the debounce timer for the Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# link debounce time 0switch(config-if)#Configuring the Interface Speed and Duplex Mode
The interface speed and duplex mode are interrelated, so you should configure both of their parameters at the same time.
To see which speeds and duplex modes you can configure together for Ethernet and management interfaces, see Table 2-2.
Note
BEFORE YOU BEGIN
Make sure that the remote port has a speed setting that supports your changes for the local port. If you want to set the local port to use a specific speed, you must set the remote port for the same speed or set the local port to autonegotiate the speed.
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This example shows how to set the speed of Ethernet port 1 on the 48-port 10/100/1000 module in slot 3 to 1000 Mb/s and full-duplex mode:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# speed 1000switch(config-if)# duplex fullswitch(config-if)#Configuring the Flow Control
For Ethernet ports that run at 1 Gb/s or faster, you can enable or disable the port's ability to send and receive flow-control pause frames. For Ethernet ports that run slower than 1 Gb/s, you can enable or disable only the port's ability to receive pause frames.
When enabling flow control for the local port, you either fully enable the local port to send or receive frames regardless of the flow-control setting of the remote port, or you set the local port to use the desired setting used by the remote port. If you enable both the local and remote port for flow control, or set the desired flow control of the other port, or set a combination of those two states, flow control is enabled for those ports.
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BEFORE YOU BEGIN
Make sure that the remote port has the corresponding setting for the flow control that you need. If you want the local port to send flow-control pause frames, make sure that the remote port has a receive parameter set to on or desired. If you want the local port to receive flow-control frames, make sure that the remote port has a send parameter set to on or desired. If you do not want to use flow control, you can set the remote port's send and receive parameters to off.
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This example shows how to set Ethernet port 3/1 to send flow control pause frames:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# flowcontrol send onswitch(config-if)#Configuring the MTU Size
You can configure the maximum transmission unit (MTU) size for Layer 2 and Layer 3 Ethernet interfaces. For Layer 3 interfaces, you can configure the MTU to be between 576 and 9216 bytes (even values are required). For Layer 2 interfaces, you can configure the MTU to be either the system default MTU (1500 bytes) or the system jumbo MTU size (which has the default size of 9216 bytes).
Note
By default, Cisco NX-OS configures Layer 3 parameters. If you want to configure Layer 2 parameters, you need to switch the port mode to Layer 2.You can change the port mode by using the switchport command.
After changing the port mode to Layer 2, you can return to configuring Layer 3 interfaces by changing the port mode again, by using the no switchport command.
This section includes the following topics:
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Configuring the Interface MTU Size
For Layer 3 interfaces, you can configure an MTU size that is between 576 and 9216 bytes.
For Layer 2 interfaces, you can configure all Layer 2 interfaces to use either the default MTU size (1500 bytes) or the system jumbo MTU size (default size of 9216 bytes).
If you need to use a different system jumbo MTU size for Layer 2 interfaces, see the "Configuring the System Jumbo MTU Size" section.
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This example shows how to configure the Layer 2 Ethernet port 3/1 with the default MTU size (1500):
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# switchportswitch(config-if)# mtu 1500switch(config-if)#Configuring the System Jumbo MTU Size
You can configure the system jumbo MTU size, which can be used to specify the MTU size for Layer 2 interfaces. You can specify an even number between 1500 and 9216. If you do not configure the system jumbo MTU size, it defaults to 1500 bytes.
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This example shows how to configure the system jumbo MTU as 8000 bytes and how to change the MTU specification for an interface that was configured with the previous jumbo MTU size:
switch# config tswitch(config)# system jumbomtu 8000switch(config)# show running-configswitch(config)# interface ethernet 2/2switch(config-if)# switchportswitch(config-if)# mtu 4608switch(config-if)#Configuring the Bandwidth
You can configure the bandwidth for Ethernet interfaces. The physical level uses an unchangeable bandwidth of 1 GB, but you can configure a value of 1 to 10,000,000 Kb for Level 3 protocols.
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This example shows how to configure an informational value of 1,000,000 Kb for the Ethernet slot 3, port 1 interface bandwidth parameter:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# bandwidth 1000000switch(config-if)#Configuring the Throughput Delay
You can configure the interface throughput delay for Ethernet interfaces. The actual delay time does not change, but you can set an informational value between 1 and 16777215, where the value represents the number of tens of microseconds.
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This example shows how to configure the throughput-delay time so that one interface is preferred over another. A lower delay value is preferred over a higher value. In this example, Ethernet 7/48 is preferred over 7/47. The default delay for 7/48 is less than the configured value on 7/47, which is set for the highest value (16777215):
switch# config tswitch(config)# interface ethernet 7/47switch(config-if)# delay 16777215switch(config-if)# ip address 192.168.10.1/24switch(config-if)# ip router eigrp 10switch(config-if)# no shutdownswitch(config-if)# exitswitch(config)# interface ethernet 7/48switch(config-if)# ip address 192.168.11.1/24switch(config-if)# ip router eigrp 10switch(config-if)# no shutdownswitch(config-if)#
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Shutting Down and Activating the Interface
You can shut down and restart Ethernet or management interfaces. When you shut down interfaces, they become disabled and all monitoring displays show them as being down. This information is communicated to other network servers through all dynamic routing protocols. When the interfaces are shut down, the interface is not included in any routing updates. To activate the interface, you must restart the device.
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This example shows how to change the administrative status for Ethernet port 3/1 from disabled to enabled:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# shutdownswitch(config-if)# no shutdownswitch(config-if)#Configuring the UDLD Mode
You can configure normal or aggressive unidirectional link detection (UDLD) modes for Ethernet interfaces on devices configured to run UDLD. Before you can enable a UDLD mode for an interface, you must make sure that UDLD is already enabled on the device that includes the interface. UDLD must also be enabled on the other linked interface and its device.
Table 2-6 lists CLI details to enable and disable UDLD on different interfaces.
To use the normal UDLD mode, you must configure one of the ports for normal mode and configure the other port for the normal or aggressive mode. To use the aggressive UDLD mode, you must configure both ports for the aggressive mode.
By default, UDLD is disabled for the 48-port, 10/100/1000 Ethernet module ports but the normal UDLD mode is enabled for the 32-port, 10-Gigabit Ethernet module ports.
BEFORE YOU BEGIN
You must enable UDLD for the other linked port and its device.
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Step 1
{
Example:
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|Enters configuration mode.
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feature udld
Example:
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config tEnables UDLD for the device.
no feature udld
Example:
switch# config t
switch(config)#Disables UDLD for the device.
Step 3
udld message-time seconds
Example:
switch(config)# udld message-time 30
switch(config)#
(Optional) Specifies the interval between sending UDLD messages. The range is 7 to 90 seconds, and the default is 15 seconds.
Step 4
udld aggressive
Example:
switch(config)# udld aggressive
switch(config)#
(Optional) Specifies UDLD mode to be aggressive.
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Step 5
interface ethernet slot/port
Example:
switch(config)# feature udld
switch(config)#(Optional) Specifies an interface to configure, and enters interface configuration mode.
Step 6
udld {enable | disable}
Example:
switch(config-if)# udld enable
switch(config-if)#
(Optional) Enables UDLD on the specified copper port or disables UDLD on the specified fiber port.
To enable UDLD on copper ports. the command is udld enable. To enable UDLD on fiber ports, the command is no udld disable. See Table 2-6 for more details.
Step 7
show udld [ethernet slot/port | global | neighbors]
Example:
switch(config)# show udld
switch(config)#
(Optional) Displays the UDLD status.
Step 8
exit
Example:
switch(config-if-range)# exit
switch(config)#
Exits the interface mode.
Step 9
copy running-config startup-config
Example:
switch(config)# copy running-config startup-config
(Optional) Copies the running configuration to the startup configuration.
This example shows how to enable the UDLD for the device:
switch# config tswitch(config)# feature udldswitch(config)#This example shows how to set the UDLD message interval to 30 seconds:
switch# config tswitch(config)# feature udldswitch(config)# udld message-time 30switch(config)#This example shows how to enable the aggressive UDLD mode for fiber interfaces:
switch# config tswitch(config)# feature udldswitch(config)# udld aggressiveswitch(config)#This example shows how to enable the aggressive UDLD mode for the copper interface Ethernet 3/1:
switch# configure terminalswitch(config)# feature udldswitch(config)# udld aggressiveswitch(config)# interface ethernet 3/1switch(config-if-range)# udld enableswitch(config-if-range)#This example shows how to disable UDLD for Ethernet port 3/1:
switch# configure terminalswitch(config)# interface ethernet 3/1switch(config-if-range)# no udld enableswitch(config-if-range)# exitThis example shows how to disable UDLD for the device:
switch# config tswitch(config)# no feature udldswitch(config)# exitConfiguring the Carrier Delay Timer
The carrier delay timer sets a time during which all link-down/link-up events are not detected by any of the other software on the device. When you configure a longer carrier delay time, fewer link-down/link-up events are recorded. When you configure the carrier delay time to 0, the device detects each link-down/link-up event.
Note
BEFORE YOU BEGIN
Ensure that you are in VLAN interface mode. You cannot configure the carrier delay timer in any other interface mode.
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This example shows how to set the carrier delay timer to 20 seconds for VLAN 5:
switch# config tswitch(config)# interface vlan 5switch(config-if)# carrier-delay 20switch(config-if)#Configuring Port Profiles
You can apply several configuration parameters to a range of interfaces simultaneously. All the interfaces in the range must be the same type. You can also inherit the configurations from one port profile into another port profile. The system supports four levels of inheritance.
This section includes the following topics:
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Creating a Port Profile
You can create a port profile on the device. Each port profile must have a unique name across types and the network.
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This example shows how to create a port profile named test for tunnel interfaces:
switch# config tswitch(config)# port-profile type tunnel testswitch(config-ppm)#Entering Port-Profile Configuration Mode and Modifying a Port Profile
You can enter the port-profile configuration mode and modify a port profile. To modify the port profile, you must be in the port-profile configuration mode.
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This example shows enter the port-profile configuration mode for the specified port profile and bring all the interfaces administratively up:
switch# config tswitch(config)# port-profile type tunnel testswitch(config-ppm)# no shutdownswitch(config-ppm)#Assigning a Port Profile to a Range of Interfaces
You can assign a port profile to an interface or to a range of interfaces. All the interfaces must be the same type.
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This example shows how to assign the port profile named adam to Ethernet interfaces 7/3 to 7/5, 10/2, and 11/20 to 11/25:
switch# config tswitch(config)# interface ethernet 7/3-5, 10/2, 11/20-25switch(config-if)# inherit port-profile adamswitch(config-if)#Enabling a Specific Port Profile
To apply the port-profile configurations to the interfaces, you must enable the specific port profile. You can configure and inherit a port profile onto a range of interfaces before you enable that port profile. You would then enable that port profile for the configurations to take effect on the specified interfaces.
If you inherit one or more port profiles onto an original port profile, only the last inherited port profile must be enabled; the system assumes that the underlying port profiles are enabled.
You must be in the port-profile configuration mode to enable or disable port profiles.
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This example shows how to enter the port-profile configuration mode and enable the port profile:
switch# config tswitch(config)# port-profile type tunnel testswitch(config-ppm)# state enabledswitch(config-ppm)#Inheriting a Port Profile
You can inherit a port profile onto an existing port profile. The system supports four levels of inheritance.
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This example shows how to inherit the port profile named adam onto the port profile named test:
switch# config tswitch(config)# port-profile testswitch(config-ppm)# inherit port-profile adamswitch(config-ppm)#Removing a Port Profile from a Range of Interfaces
You can remove a port profile from some or all of the interfaces to which you have applied the profile. You do this in the interfaces configuration mode.
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This example shows how to remove the port profile named adam from Ethernet interfaces 7/3 to 7/5, 10/2, and 11/20 to 11/25:
switch# config tswitch(config)# interface ethernet 7/3-5, 10/2, 11/20-25switch(config-if)# no inherit port-profile adamswitch(config-if)#Removing an Inherited Port Profile
You can remove an inherited port profile. You do this in the port-profile mode.
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This example shows how to remove the inherited port profile named adam from the port profile named test:
switch# config tswitch(config)# port-profile testswitch(config-ppm)# no inherit port-profile adamswitch(config-ppm)#Verifying the Basic Interface Parameters
You can verify the basic interface parameters by displaying their values. You can also clear the counters listed when you display the parameter values.
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DETAILED STEPS
To display basic interface configuration information, perform one of the following tasks:
For detailed information about the fields in the output from these commands, see the Cisco NX-OS Interfaces Configuration Command Reference.
Displaying and Clearing the Interface Counters
You can display and clear interface counters using Cisco NX-OS. This section discusses the following topics:
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Displaying Interface Statistics
You can set up to three sampling intervals for statistics collections on interfaces.
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This example shows how to set the three sample intervals for the Ethernet port 3/1:
switch# config tswitch(config)# interface ethernet 3/1switch(config-if)# load-interval counter 1 60switch(config-if)# load-interval counter 2 135switch(config-if)# load-interval counter 3 225switch(config-if)#Clearing Interface Counters
You can clear the Ethernet and management interface counters using the clear counters command. You can perform this task from the configuration mode or interface configuration mode.
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This example shows how to clear and reset the counters on Ethernet port 5/5:
switch# clear counters ethernet 5/5switch#Default Settings
Table 2-7 lists the default settings for the basic interface parameters.
Additional References
For additional information related to implementing Feature-1, see the following sections:
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Related Documents
Standards
No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.
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Feature History for Configuring Basic Interface Parameters
Table 2-8 lists the release history for this feature.
