Cisco Nexus 6000 Series NX-OS Interfaces Configuration Guide, Release 7.x
Configuring Port Channels
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Contents

Configuring Port Channels

This chapter contains the following sections:

Information About Port Channels

A port channel bundles individual interfaces into a group to provide increased bandwidth and redundancy. Port channeling also load balances traffic across these physical interfaces. The port channel stays operational as long as at least one physical interface within the port channel is operational.

You create a port channel by bundling compatible interfaces. You can configure and run either static port channels or port channels running the Link Aggregation Control Protocol (LACP).

Any configuration changes that you apply to the port channel are applied to each member interface of that port channel. For example, if you configure Spanning Tree Protocol (STP) parameters on the port channel, Cisco NX-OS applies those parameters to each interface in the port channel.

You can use static port channels, with no associated protocol, for a simplified configuration. For more efficient use of the port channel, you can use the Link Aggregation Control Protocol (LACP), which is defined in IEEE 802.3ad. When you use LACP, the link passes protocol packets.

Related Concepts

Understanding Port Channels

Using port channels, Cisco NX-OS provides wider bandwidth, redundancy, and load balancing across the channels.

You can collect ports into a static port channel or you can enable the Link Aggregation Control Protocol (LACP). Configuring port channels with LACP requires slightly different steps than configuring static port channels. For information on port channel configuration limits, see the Verified Scalability document for your platform. For more information about load balancing, see Load Balancing Using Port Channels.


Note


Cisco NX-OS does not support Port Aggregation Protocol (PAgP) for port channels.


A port channel bundles individual links into a channel group to create a single logical link that provides the aggregate bandwidth of several physical links. If a member port within a port channel fails, traffic previously carried over the failed link switches to the remaining member ports within the port channel.

Each port can be in only one port channel. All the ports in a port channel must be compatible; they must use the same speed and operate in full-duplex mode. When you are running static port channels without LACP, the individual links are all in the on channel mode; you cannot change this mode without enabling LACP.


Note


You cannot change the mode from ON to Active or from ON to Passive.


You can create a port channel directly by creating the port-channel interface, or you can create a channel group that acts to aggregate individual ports into a bundle. When you associate an interface with a channel group, Cisco NX-OS creates a matching port channel automatically if the port channel does not already exist. You can also create the port channel first. In this instance, Cisco NX-OS creates an empty channel group with the same channel number as the port channel and takes the default configuration.


Note


A port channel is operationally up when at least one of the member ports is up and that port’s status is channeling. The port channel is operationally down when all member ports are operationally down.


Guidelines and Limitations for Port Channel Configuration

Port channels can be configured in one of two ways: either in global configuration mode or in switch profile mode. Consider the following guidelines and limitations when configuring port channels via the configuration synchronization feature in Cisco NX-OS:

  • Once a port channel is configured using switch profile mode, it cannot be configured using global configuration (config terminal) mode.

    Note


    Several port channel sub-commands are not configurable in switch profile mode. These commands can be configured from global configuration mode even if the port channel is created and configured in switch profile mode.

    For example, the following command can only be configured in global configuration mode:

    switchport private-vlan association trunk primary-vlan secondary-vlan


  • Shutdown and no shutdown can be configured in either global configuration mode or switch profile mode.
  • If a port channel is created in global configuration mode, channel groups including member interfaces must also be created using global configuration mode.
  • Port channels that are configured within switch profile mode may have members both inside and outside of a switch profile.
  • If you want to import a member interface to a switch profile, the port channel that corresponds with the member interface must also be present within the switch profile.

For more information on switch profiles, see the Cisco Nexus 6000 Series NX-OS System Management Configuration Guide.

Compatibility Requirements

When you add an interface to a port channel group, Cisco NX-OS checks certain interface attributes to ensure that the interface is compatible with the channel group. Cisco NX-OS also checks a number of operational attributes for an interface before allowing that interface to participate in the port-channel aggregation.

The compatibility check includes the following operational attributes:

  • Port mode
  • Access VLAN
  • Trunk native VLAN
  • Allowed VLAN list
  • Speed
  • 802.3x flow control setting
  • MTU
  • Broadcast/Unicast/Multicast Storm Control setting
  • Priority-Flow-Control
  • Untagged CoS

Use the show port-channel compatibility-parameters command to see the full list of compatibility checks that Cisco NX-OS uses.

You can only add interfaces configured with the channel mode set to on to static port channels. You can also only add interfaces configured with the channel mode as active or passive to port channels that are running LACP. You can configure these attributes on an individual member port.

When the interface joins a port channel, the following individual parameters are replaced with the values on the port channel:

  • Bandwidth
  • MAC address
  • Spanning Tree Protocol

The following interface parameters remain unaffected when the interface joins a port channel:

  • Description
  • CDP
  • LACP port priority
  • Debounce

After you enable forcing a port to be added to a channel group by entering the channel-group force command, the following two conditions occur:

  • When an interface joins a port channel, the following parameters are removed and they are operationally replaced with the values on the port channel; however, this change will not be reflected in the running configuration for the interface:
    • QoS
    • Bandwidth
    • Delay
    • STP
    • Service policy
    • ACLs
  • When an interface joins or leaves a port channel, the following parameters remain unaffected:
    • Beacon
    • Description
    • CDP
    • LACP port priority
    • Debounce
    • UDLD
    • Shutdown
    • SNMP traps

Load Balancing Using Port Channels

Cisco NX-OS load balances traffic across all operational interfaces in a port channel by reducing part of the binary pattern formed from the addresses in the frame to a numerical value that selects one of the links in the channel. Port channels provide load balancing by default.

The basic configuration uses the following criteria to select the link:
  • For a Layer 2 frame, it uses the source and destination MAC addresses.
  • For a Layer 3 frame, it uses the source and destination MAC addresses and the source and destination IP addresses.
  • For a Layer 4 frame, it uses the source and destination MAC addresses and the source and destination IP addresses.

    Note


    You have the option to include the source and destination port number for the Layer 4 frame.


You can configure the switch to use one of the following methods (see the following table for more details) to load balance across the port channel:

  • Destination MAC address
  • Source MAC address
  • Source and destination MAC address
  • Destination IP address
  • Source IP address
  • Source and destination IP address
  • Destination TCP/UDP port number
  • Source TCP/UDP port number
  • Source and destination TCP/UDP port number
Table 1  Port Channel Load-Balancing Criteria

Configuration

Layer 2 Criteria

Layer 3 Criteria

Layer 4 Criteria

Destination MAC

Destination MAC

Destination MAC

Destination MAC

Source MAC

Source MAC

Source MAC

Source MAC

Source and destination MAC

Source and destination MAC

Source and destination MAC

Source and destination MAC

Destination IP

Destination MAC

Destination MAC, destination IP

Destination MAC, destination IP

Source IP

Source MAC

Source MAC, source IP

Source MAC, source IP

Source and destination IP

Source and destination MAC

Source and destination MAC, source and destination IP

Source and destination MAC, source and destination IP

Destination TCP/UDP port

Destination MAC

Destination MAC, destination IP

Destination MAC, destination IP, destination port

Source TCP/UDP port

Source MAC

Source MAC, source IP

Source MAC, source IP, source port

Source and destination TCP/UDP port

Source and destination MAC

Source and destination MAC, source and destination IP

Source and destination MAC, source and destination IP, source and destination port

Use the option that provides the balance criteria with the greatest variety in your configuration. For example, if the traffic on a port channel is going only to a single MAC address and you use the destination MAC address as the basis of port-channel load balancing, the port channel always chooses the same link in that port channel; using source addresses or IP addresses might result in better load balancing.

Understanding LACP

LACP Overview


Note


You must enable the LACP feature before you can configure and use LACP functions.


The following figure shows how individual links can be combined into LACP port channels and channel groups as well as function as individual links.

Figure 1. Individual Links Combined into a Port Channel

With LACP, just like with static port channels, you can bundle up to 16 interfaces in a channel group.


Note


When you delete the port channel, Cisco NX-OS automatically deletes the associated channel group. All member interfaces revert to their previous configuration.


You cannot disable LACP while any LACP configurations are present.

LACP ID Parameters

LACP uses the following parameters:

  • LACP system priority—Each system that runs LACP has an LACP system priority value. You can accept the default value of 32768 for this parameter, or you can configure a value between 1 and 65535. LACP uses the system priority with the MAC address to form the system ID and also uses the system priority during negotiation with other devices. A higher system priority value means a lower priority.

Note


The LACP system ID is the combination of the LACP system priority value and the MAC address.


  • LACP port priority—Each port configured to use LACP has an LACP port priority. You can accept the default value of 32768 for the LACP port priority, or you can configure a value between 1 and 65535. LACP uses the port priority with the port number to form the port identifier. LACP uses the port priority to decide which ports should be put in standby mode when there is a limitation that prevents all compatible ports from aggregating and which ports should be put into active mode. A higher port priority value means a lower priority for LACP. You can configure the port priority so that specified ports have a lower priority for LACP and are most likely to be chosen as active links, rather than hot-standby links.
  • LACP administrative key—LACP automatically configures an administrative key value equal to the channel-group number on each port configured to use LACP. The administrative key defines the ability of a port to aggregate with other ports. A port’s ability to aggregate with other ports is determined by these factors:
    • Port physical characteristics, such as the data rate, the duplex capability, and the point-to-point or shared medium state
    • Configuration restrictions that you establish

Channel Modes

Individual interfaces in port channels are configured with channel modes. When you run static port channels, with no protocol, the channel mode is always set to on. After you enable LACP globally on the device, you enable LACP for each channel by setting the channel mode for each interface to active or passive. You can configure either channel mode for individual links in the LACP channel group.


Note


You must enable LACP globally before you can configure an interface in either the active or passive channel mode.


The following table describes the channel modes.

Table 2 Channel Modes for Individual Links in a Port Channel

Channel Mode

Description

passive

LACP mode that places a port into a passive negotiating state, in which the port responds to LACP packets that it receives but does not initiate LACP negotiation.

active

LACP mode that places a port into an active negotiating state, in which the port initiates negotiations with other ports by sending LACP packets.

on

All static port channels, that is, that are not running LACP, remain in this mode. If you attempt to change the channel mode to active or passive before enabling LACP, the device returns an error message.

You enable LACP on each channel by configuring the interface in that channel for the channel mode as either active or passive. When an LACP attempts to negotiate with an interface in the on state, it does not receive any LACP packets and becomes an individual link with that interface; it does not join the LACP channel group.

Both the passive and active modes allow LACP to negotiate between ports to determine if they can form a port channel, based on criteria such as the port speed and the trunking state. The passive mode is useful when you do not know whether the remote system, or partner, supports LACP.

Ports can form an LACP port channel when they are in different LACP modes as long as the modes are compatible as in the following examples:

  • A port in active mode can form a port channel successfully with another port that is in active mode.
  • A port in active mode can form a port channel with another port in passive mode.
  • A port in passive mode cannot form a port channel with another port that is also in passive mode because neither port will initiate negotiation.
  • A port in on mode is not running LACP.

LACP Marker Responders

Using port channels, data traffic may be dynamically redistributed due to either a link failure or load balancing. LACP uses the Marker Protocol to ensure that frames are not duplicated or reordered because of this redistribution. Cisco NX-OS supports only Marker Responders.

LACP-Enabled and Static Port Channel Differences

The following table provides a brief summary of major differences between port channels with LACP enabled and static port channels. For information about the maximum configuration limits, see the Verified Scalability document for your device.

Table 3 Port Channels with LACP Enabled and Static Port Channels

Configurations

Port Channels with LACP Enabled

Static Port Channels

Protocol applied

Enable globally.

Not applicable.

Channel mode of links

Can be either:

  • Active
  • Passive

Can only be On.

LACP Port-Channel MinLinks and MaxBundle

A port channel aggregates similar ports to provide increased bandwidth in a single manageable interface.

The introduction of the minlinks and maxbundle feature further refines LACP port-channel operation and provides increased bandwidth in one manageable interface.

The LACP port-channel MinLink feature does the following:

  • Configures the minimum number of ports that must be linked up and bundled in the LACP port channel.
  • Prevents the low-bandwidth LACP port channel from becoming active.
  • Causes the LACP port channel to become inactive if there are few active members ports to supply the required minimum bandwidth.

The LACP MaxBundle defines the maximum number of bundled ports allowed in a LACP port channel.

The LACP MaxBundle feature does the following:

  • Defines an upper limit on the number of bundled ports in an LACP port channel.
  • Allows hot-standby ports with fewer bundled ports. (For example, in an LACP port channel with five ports, you can designate two of those ports as hot-standby ports.)

Note


The minlink and maxbundle feature works only with LACP port channels. However, the device allows you to configure this feature in non-LACP port channels, but the feature is not operational.

The LACP minlink and maxbundle configurations are not applicable to FEX HIF port-channels.

The minlink/maxbundle configuration can be applied to a non-LACP HIF PO, but the feature is not operational. Configuring a minlink/maxbundle configuration on a LACP HIF PO is not allowed and is rejected.


Configuring Port Channels

Default Settings

Table 4 Default Port-Channel Parameters

Parameters

Default

Port channel

Admin up

Load balancing method for Layer 3 interfaces

Source and destination IP address

Load balancing method for Layer 2 interfaces

Source and destination MAC address

Load balancing per module

Disabled

RBH modulo mode

Disabled

LACP

Disabled

Channel mode

on

LACP system priority

32768

LACP port priority

32678

Minimum links for LACP

1

Minimum links for FEX fabric port channel

1

Maxbundle

16

LACP Port-Channel Min Links

A port channel aggregates similar ports to provide increased bandwidth in a single manageable interface.

The introduction of the minimum links feature further refines LACP port-channel operation and provides increased bandwidth in one manageable interface.

The LACP port-channel minimum links feature does the following:

  • Configures the minimum number of ports that must be linked up and bundled in the LACP port channel.
  • Prevents the low-bandwidth LACP port channel from becoming active.
  • Causes the LACP port channel to become inactive if there are few active members ports to supply the required minimum bandwidth.

Note


The minimum links feature works only with LACP port channels. However, the device allows you to configure this feature in non-LACP port channels, but the feature is not operational.


Creating a Port Channel

You can create a port channel before creating a channel group. Cisco NX-OS automatically creates the associated channel group.


Note


If you want LACP-based port channels, you need to enable LACP.


Procedure
      Command or Action Purpose
    Step 1 switch# configure terminal  

    Enters global configuration mode.

     
    Step 2 switch(config)# interface port-channel channel-number  

    Specifies the port-channel interface to configure, and enters the interface configuration mode. The range is from 1 to 4096. Cisco NX-OS automatically creates the channel group if it does not already exist.

     
    Step 3 switch(config)# no interface port-channel channel-number  

    Removes the port channel and deletes the associated channel group.

     

    This example shows how to create a port channel:

    switch# configure terminal
    switch (config)# interface port-channel 1

    Adding a Port to a Port Channel

    You can add a port to a new channel group or to a channel group that already contains ports. Cisco NX-OS creates the port channel associated with this channel group if the port channel does not already exist.


    Note


    If you want LACP-based port channels, you need to enable LACP.


    Procedure
        Command or Action Purpose
      Step 1 switch# configure terminal 

      Enters global configuration mode.

       
      Step 2 switch(config)# interface type slot/port  

      Specifies the interface that you want to add to a channel group and enters the interface configuration mode.

      Note   

      If this is a 10G breakout port, the slot/port syntax is slot/QSFP-module/port.

       
      Step 3 switch(config-if)# switchport mode trunk   (Optional)

      Configures the interface as a trunk port.

       
      Step 4 switch(config-if)# switchport trunk {allowed vlan vlan-id | native vlan vlan-id}   (Optional)

      Configures necessary parameters for a trunk port.

       
      Step 5 switch(config-if)# channel-group channel-number  

      Configures the port in a channel group and sets the mode. The channel-number range is from 1 to 4096. Cisco NX-OS creates the port channel associated with this channel group if the port channel does not already exist. This is called implicit port channel creation.

       
      Step 6 switch(config-if)# no channel-group   (Optional)

      Removes the port from the channel group. The port reverts to its original configuration.

       

      This example shows how to add an Ethernet interface 1/4 to channel group 1:

      switch# configure terminal
      switch (config)# interface ethernet 1/4
      switch(config-if)# switchport mode trunk
      switch(config-if)# channel-group 1
      

      Configuring Load Balancing Using Port Channels

      You can configure the load-balancing algorithm for port channels that applies to the entire device.


      Note


      If you want LACP-based port channels, you need to enable LACP.


      Procedure
          Command or Action Purpose
        Step 1 switch# configure terminal  

        Enters global configuration mode.

         
        Step 2 switch(config)# port-channel load-balance ethernet {[destination-ip | destination-mac | destination-port | source-dest-ip | source-dest-mac | source-dest-port | source-ip | source-mac | source-port] crc-poly}  

        Specifies the load-balancing algorithm for the device. The range depends on the device. The default is source-dest-mac.

         
        Step 3 switch(config)# no port-channel load-balance ethernet   (Optional)

        Restores the default load-balancing algorithm of source-dest-mac.

         
        Step 4 switch# show port-channel load-balance   (Optional)

        Displays the port-channel load-balancing algorithm.

         

        This example shows how to configure source IP load balancing for port channels:

        switch# configure terminal
        switch (config)# port-channel load-balance ethernet source-ip

        Configuring Hardware Hashing for Multicast Traffic

        By default, ingress multicast traffic on any port in the switch selects a particular port channel member to egress the traffic. You can configure hardware hashing for multicast traffic to reduce potential bandwidth issues and to provide effective load balancing of the ingress multicast traffic. Use the hardware multicast hw-hash command to enable hardware hashing. To restore the default, use the no hardware multicast hw-hash command.

        Procedure
            Command or Action Purpose
          Step 1 switch# configure terminal
           

          Enters global configuration mode.

           
          Step 2 switch(config)# interface port-channel channel-number
           

          Selects the port channel and enters the interface configuration mode.

           
          Step 3 switch(config-if)# [no] hardware multicast hw-hash
           

          Configures hardware hashing for the specified port channel.

           

          This example shows how to configure hardware hashing on a port channel:

          switch# configure terminal
          
          switch (config)# interface port-channel 21
          
          switch(config-if)# hardware multicast hw-hash
          
          

          This example shows how to remove hardware hashing from a port channel:

          switch# configure terminal
          
          switch (config)# interface port-channel 21
          
          switch(config-if)# no hardware multicast hw-hash
          

          Enabling LACP

          LACP is disabled by default; you must enable LACP before you begin LACP configuration. You cannot disable LACP while any LACP configuration is present.

          LACP learns the capabilities of LAN port groups dynamically and informs the other LAN ports. Once LACP identifies correctly matched Ethernet links, it facilitates grouping the links into an port channel. The port channel is then added to the spanning tree as a single bridge port.

          Procedure
              Command or Action Purpose
            Step 1 switch# configure terminal
             

            Enters global configuration mode.

             
            Step 2 switch(config)# feature lacp
             

            Enables LACP on the switch.

             
            Step 3 switch(config)# show feature
             
            (Optional)

            Displays enabled features.

             

            This example shows how to enable LACP:

            switch# configure terminal
            
            switch(config)# feature lacp
            
             

            Configuring the Channel Mode for a Port

            You can configure the channel mode for each individual link in the LACP port channel as active or passive. This channel configuration mode allows the link to operate with LACP.

            When you configure port channels with no associated protocol, all interfaces on both sides of the link remain in the on channel mode.

            Before You Begin

            Ensure that you have enabled the LACP feature.

            Procedure
                Command or Action Purpose
              Step 1 switch# configure terminal 

              Enters global configuration mode.

               
              Step 2 switch(config)# interface type slot/port
               

              Specifies the interface to configure, and enters the interface configuration mode.

              Note   

              If this is a 10G breakout port, the slot/port syntax is slot/QSFP-module/port.

               
              Step 3 switch(config-if)# channel-group channel-number [force] [mode {on | active | passive}]
               

              Specifies the port mode for the link in a port channel. After LACP is enabled, you configure each link or the entire channel as active or passive.

              force—Specifies that the LAN port be forcefully added to the channel group.

              mode—Specifies the port channel mode of the interface.

              active—Specifies that when you enable LACP, this command enables LACP on the specified interface. The interface is in an active negotiating state in which the port initiates negotiations with other ports by sending LACP packets.

              on—(Default mode) Specifies that all port channels that are not running LACP remain in this mode.

              passive—Enables LACP only if an LACP device is detected. The interface is in a passive negotiation state in which the port responds to LACP packets that it receives but does not initiate LACP negotiation.

              When you run port channels with no associated protocol, the channel mode is always on.

               
              Step 4 switch(config-if)# no channel-group number mode
               

              Returns the port mode to on for the specified interface.

               

              This example shows how to set the LACP-enabled interface to active port-channel mode for Ethernet interface 1/4 in channel group 5:

              switch# configure terminal
              switch (config)# interface ethernet 1/4
              switch(config-if)# channel-group 5 mode active
              
              

              Configuring LACP Port-Channel Minimum Links

              You can configure the LACP minimum links feature. Although minimum links work only in LACP, you can enter the CLI commands for this feature for non-LACP port channels, but these commands are nonoperational.

              Before You Begin

              Ensure that you are in the correct port-channel interface.

              Procedure
                  Command or Action Purpose
                Step 1 switch# configure terminal 

                Enters global configuration mode.

                 
                Step 2 switch(config)# interface port-channel number 

                Specifies the interface to configure, and enters the interface configuration mode.

                 
                Step 3 switch(config-if)# lacp min-links number 

                Specifies the port-channel interface to configure the number of minimum links and enters the interface configuration mode. The range is from 1 to 16.

                 
                Step 4 switch(config-if)# show running-config interface port-channel number  (Optional)

                Displays the port-channel minimum links configuration.

                 

                The following example shows how to configure LACP port-channel minimum links.

                switch# configure terminal
                switch(config)# interface port-channel 3
                switch(config-if)# lacp min-links 3
                switch(config-if)# show running-config interface port-channel 3
                interface port-channel 3
                lacp min-links 3
                

                Configuring the LACP Port-Channel MaxBundle

                You can configure the LACP minlinks feature. Although minlinks and maxbundles work only in LACP, you can enter the CLI commands for these features for non-LACP port channels, but these commands are nonoperational.

                Before You Begin

                Ensure that you are in the correct port-channel interface.

                Procedure
                    Command or Action Purpose
                  Step 1 switch# configure terminal 

                  Enters global configuration mode.

                   
                  Step 2 switch(config)# interface port-channel number  

                  Specifies the interface to configure, and enters the interface configuration mode.

                   
                  Step 3 switch(config-if)# lacp max-bundle number  

                  Specifies the port-channel interface to configure max-bundle, and enters the interface configuration mode.

                  The default value for the port-channel max-bundle is 16. The allowed range is from 1 to 16.

                  Note   

                  Even if the default value is 16, the number of active members in a port channel is the minimum of the pc_max_links_config and pc_max_active_members that is allowed in the port channel. The min-links and max-bundle features work well when both ends of the port-channel are configured with the same value. Mismatched min/max-bundle values might result in port flap, traffic drops, and unnecessary port suspension.

                   
                  Step 4 switch(config-if)# show running config interface port-channel number    

                  This example shows how to configure the port channel interface max-bundle on module 3:

                  switch# configure terminal
                  switch(config)# lacp max-bundle 3

                  Configuring the LACP Fast Timer Rate

                  You can change the LACP timer rate to modify the duration of the LACP timeout. Use the lacp rate command to set the rate at which LACP control packets are sent to an LACP-supported interface. You can change the timeout rate from the default rate (30 seconds) to the fast rate (1 second). This command is supported only on LACP-enabled interfaces.

                  Before You Begin

                  Ensure that you have enabled the LACP feature.

                  Procedure
                      Command or Action Purpose
                    Step 1 switch# configure terminal 

                    Enters global configuration mode.

                     
                    Step 2 switch(config)# interface type slot/port
                     

                    Specifies the interface to configure and enters the interface configuration mode.

                    Note   

                    If this is a 10G breakout port, the slot/port syntax is slot/QSFP-module/port.

                     
                    Step 3 switch(config-if)# lacp rate fast
                     

                    Configures the fast rate (one second) at which LACP control packets are sent to an LACP-supported interface.

                     

                    This example shows how to configure the LACP fast rate on Ethernet interface 1/4:

                    switch# configure terminal
                    switch(config)# interface ethernet 1/4
                    switch(config-if)# lacp rate fast

                    This example shows how to restore the LACP default rate (30 seconds) on Ethernet interface 1/4.

                    switch# configure terminal
                    switch(config)# interface ethernet 1/4
                    switch(config-if)# no lacp rate fast

                    Configuring the LACP System Priority and System ID

                    The LACP system ID is the combination of the LACP system priority value and the MAC address.

                    Before You Begin

                    Ensure that you have enabled the LACP feature.

                    Procedure
                        Command or Action Purpose
                      Step 1 switch# configure terminal
                       

                      Enters global configuration mode.

                       
                      Step 2 switch(config)# lacp system-priority priority
                       

                      Configures the system priority for use with LACP. Valid values are 1 through 65535, and higher numbers have lower priority. The default value is 32768.

                       
                      Step 3 switch# show lacp system-identifier
                       
                      (Optional)

                      Displays the LACP system identifier.

                       

                      This example shows how to set the LACP system priority to 2500:

                      switch# configure terminal
                      
                      switch(config)# lacp system-priority 2500
                      
                       

                      Configuring the LACP Port Priority

                      You can configure each link in the LACP port channel for the port priority.

                      Before You Begin

                      Ensure that you have enabled the LACP feature.

                      Procedure
                          Command or Action Purpose
                        Step 1 switch# configure terminal 

                        Enters global configuration mode.

                         
                        Step 2 switch(config)# interface type slot/port
                         

                        Specifies the interface to configure, and enters the interface configuration mode.

                        Note   

                        If this is a 10G breakout port, the slot/port syntax is slot/QSFP-module/port.

                         
                        Step 3 switch(config-if)# lacp port-priority priority
                         

                        Configures the port priority for use with LACP. Valid values are 1 through 65535, and higher numbers have lower priority. The default value is 32768.

                         

                        This example shows how to set the LACP port priority for Ethernet interface 1/4 to 40000:

                        switch# configure terminal
                        switch (config)# interface ethernet 1/4
                        switch(config-if)# lacp port priority 40000

                        Disabling LACP Graceful Convergence

                        Before You Begin
                        • Enable the LACP feature.
                        • Confirm that the port channel is in the administratively down state.
                        • Ensure that you are in the correct VDC. To switch to the correct VDC, enter the switchto vdc command.
                        Procedure
                            Command or Action Purpose
                          Step 1 configure terminal


                          Example:
                          switch# configure terminal
                          switch(config)#
                           

                          Enters global configuration mode.

                           
                          Step 2 interface port-channel number


                          Example:
                          switch(config)# interface port-channel 1
                          switch(config) #
                           

                          Specifies the port channel interface to configure, and enters interface configuration mode.

                           
                          Step 3 shutdown


                          Example:
                          switch(config-if)# shutdown
                          switch(config-if) #
                           

                          Administratively shuts down the port channel.

                           
                          Step 4 no lacp graceful-convergence


                          Example:
                          switch(config-if)# no lacp graceful-convergence
                          switch(config-if) #
                           

                          Disables LACP graceful convergence on the specified port channel.

                           
                          Step 5 no shutdown


                          Example:
                          switch(config-if)# no shutdown
                          switch(config-if) #
                           

                          Administratively brings the port channel up.

                           
                          Step 6 copy running-config startup-config


                          Example:
                          switch(config-if)# copy running-config startup-config
                          
                           
                          (Optional)

                          Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

                           

                          The following example disables LACP graceful convergence on a port channel:

                          switch# configure terminal
                          switch(config) # interface port-channel 1
                          switch(config-if) # shutdown
                          switch(config-if) # no lacp graceful-convergence
                          switch(config-if) # no shutdown
                          switch(config-if) #

                          Reenabling LACP Graceful Convergence

                          Before You Begin
                          • Enable the LACP feature.
                          • Confirm that the port channel is in the administratively down state.
                          • Ensure that you are in the correct VDC. To switch to the correct VDC, enter the switchto vdc command.
                          Procedure
                              Command or Action Purpose
                            Step 1 configure terminal


                            Example:
                            switch# configure terminal
                            switch(config)#
                             

                            Enters global configuration mode.

                             
                            Step 2 interface port-channel number


                            Example:
                            switch(config)# interface port-channel 1
                            switch(config) #
                             

                            Specifies the port channel interface to configure, and enters interface configuration mode.

                             
                            Step 3 shutdown


                            Example:
                            switch(config-if)# shutdown
                            switch(config-if) #
                             

                            Administratively shuts down the port channel.

                             
                            Step 4 lacp graceful-convergence


                            Example:
                            switch(config-if)# lacp graceful-convergence
                            switch(config-if) #
                             

                            Enables LACP graceful convergence on the specified port channel.

                             
                            Step 5 no shutdown


                            Example:
                            switch(config-if)# no shutdown
                            switch(config-if) #
                             

                            Administratively brings the port channel up.

                             
                            Step 6 copy running-config startup-config


                            Example:
                            switch(config-if)# copy running-config startup-config
                            
                             
                            (Optional)

                            Saves the change persistently through reboots and restarts by copying the running configuration to the startup configuration.

                             

                            The following example disables LACP graceful convergence on a port channel:

                            switch# configure terminal
                            switch(config) # interface port-channel 1
                            switch(config-if) # shutdown
                            switch(config-if) # lacp graceful-convergence
                            switch(config-if) # no shutdown
                            switch(config-if) #

                            Verifying Port Channel Configuration

                            Use the following command to verify the port channel configuration information:

                            Command

                            Purpose

                            show interface port channelchennal-number

                            Displays the status of a port channel interface.

                            show feature

                            Displays enabled features.

                            show resource

                            Displays the number of resources currently available in the system.

                            show lacp {counters | interface type slot/port | neighbor | port-channel | system-identifier}

                            Displays LACP information.

                            Note   

                            If this is a 10G breakout port, the slot/port syntax is slot/QSFP-module/port.

                            show port-channel compatibility-parameters

                            Displays the parameters that must be the same among the member ports in order to join a port channel.

                            show port-channel database [interface port-channel channel-number]

                            Displays the aggregation state for one or more port-channel interfaces.

                            show port-channel summary

                            Displays a summary for the port channel interfaces.

                            show port-channel traffic

                            Displays the traffic statistics for port channels.

                            show port-channel usage

                            Displays the range of used and unused channel numbers.

                            show port-channel database

                            Displays information on current running of the port channel feature.

                            show port-channel load-balance

                            Displays information about load-balancing using port channels.

                            Verifying the Load-Balancing Outgoing Port ID

                            Command Guidelines

                            The show port-channel load-balance command allows you to verify which ports a given frame is hashed to on a port channel. You need to specify the VLAN and the destination MAC in order to get accurate results.

                            Note


                            Certain traffic flows are not subject to hashing such as when there is a single port in a portchannel.

                            To display the load-balancing outgoing port ID, perform one of the tasks:

                            Command

                            Purpose

                            switch# show port-channel load-balance forwarding-path interface port-channel port-channel-id vlan vlan-id dst-ip src-ip dst-mac src-mac l4-src-port port-id l4-dst-port port-id

                            Displays the outgoing port ID.

                            Example

                            This example shows how to display the load balancing outgoing port ID:

                            switch# show port-channel load-balance forwarding-path interface port-channel 10 vlan 1 dst-ip 1.225.225.225 src-ip 1.1.10.10 src-mac aa:bb:cc:dd:ee:ff l4-src-port 0 l4-dst-port 1
                            Missing params will be substituted by 0's. Load-balance Algorithm on switch: source-dest-port crc8_hash:204 Outgoing port id: Ethernet 1/1 Param(s) used to calculate load balance:
                            dst-port: 0
                            src-port: 0
                            dst-ip: 1.225.225.225
                            src-ip: 1.1.10.10
                            dst-mac: 0000.0000.0000
                            src-mac: aabb.ccdd.eeff
                            

                            Feature History for Configuring Port Channels

                            Table 5 Feature History for Configuring Port Channels

                            Feature Name

                            Release

                            Feature Information

                            Min Links

                            6.0(2)N1(2)

                            This feature was introduced.