Catalyst 6500 Series Software Configuration Guide, 8.7 - Configuring EtherChannel [Cisco Catalyst 6500 Series Switches]

Table Of Contents

Configuring EtherChannel

Understanding How EtherChannel Works

Understanding How EtherChannel Frame Distribution Works

Port Aggregation Control Protocol and Link Aggregation Control Protocol

EtherChannel Configuration Guidelines

Port Configuration Guidelines

VLAN and Trunk Configuration Guidelines

Interaction with Other Features Guidelines

Understanding How the Port Aggregation Protocol Works

PAgP Modes

PAgP Administrative Groups

PAgP EtherChannel IDs

Configuring an EtherChannel Using PAgP

Specifying the EtherChannel Protocol

Configuring an EtherChannel

Setting the EtherChannel Port Mode

Setting the EtherChannel Port Path Cost

Setting the EtherChannel VLAN Cost

Configuring EtherChannel Load Balancing

Displaying EtherChannel Traffic Utilization

Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

Disabling an EtherChannel

Understanding How the Link Aggregation Control Protocol Works

LACP Modes

LACP Parameters

Configuring an EtherChannel Using LACP

Specifying the EtherChannel Protocol

Specifying the System Priority

Specifying the Port Priority

Specifying an Administrative Key Value

Changing the Channel Mode

Specifying the Channel Path Cost

Specifying the Channel VLAN Cost

Configuring Channel Load Balancing

Clearing the LACP Statistics

Displaying EtherChannel Traffic Utilization

Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

Disabling an EtherChannel

Displaying the Spanning-Tree Information for EtherChannels

Clearing and Restoring the EtherChannel Counters

Clearing the EtherChannel Counters

Restoring the EtherChannel Counters

Configuring EtherChannel

This chapter describes how to use the command-line interface (CLI) to configure EtherChannel on the Catalyst 6500 series switches. The configuration tasks in this chapter apply to Ethernet, Fast Ethernet, Gigabit Ethernet, and 10-Gigabit Ethernet switching modules and the uplink ports on the supervisor engine.

Note For complete syntax and usage information for the commands that are used in this chapter, refer to the Catalyst 6500 Series Switch Command Reference publication.

This chapter consists of these sections:

•Understanding How EtherChannel Works

•Understanding How EtherChannel Frame Distribution Works

•Port Aggregation Control Protocol and Link Aggregation Control Protocol

•EtherChannel Configuration Guidelines

•Understanding How the Port Aggregation Protocol Works

•Configuring an EtherChannel Using PAgP

•Understanding How the Link Aggregation Control Protocol Works

•Configuring an EtherChannel Using LACP

•Clearing and Restoring the EtherChannel Counters

Note With software release 8.4(1) and later releases, you can configure EtherChannel error handling to provide for the automatic failover of traffic to another port in the EtherChannel when one of the ports in the channel exceeds a configurable error threshold. For more information, see the "Configuring EtherChannel/Link Error Handling" section on page 20-24.

Note You can use the commands in the following sections on all Ethernet ports in the Catalyst 6500 series switches.

Understanding How EtherChannel Works

EtherChannel aggregates the bandwidth of up to eight compatibly configured ports into a single logical link. Catalyst 6500 series switches support a maximum of 128 EtherChannels. All Ethernet ports on all modules, including those on a standby supervisor engine, support EtherChannel with no requirement that ports be contiguous or on the same module. All ports in each EtherChannel must be the same speed.

Note With software release 6.3(1) and later releases, due to the port ID handling by the spanning-tree feature, the maximum supported number of EtherChannels is 126 for a 6- or 9-slot chassis and 63 for a 13-slot chassis.

Note The network device to which a Catalyst 6500 series switch is connected may impose its own limits on the number of ports in an EtherChannel.

If a link within an EtherChannel fails, the traffic that was previously carried over the failed link switches to the remaining links within the EtherChannel. Inbound broadcast and multicast packets on one link in an EtherChannel are blocked from returning on any other link of the EtherChannel.

You can configure EtherChannels as trunks. After a channel is formed, configuring any port in the channel as a trunk applies the configuration to all ports in the channel. Identically configured trunk ports can be configured as an EtherChannel.

Understanding How EtherChannel Frame Distribution Works

EtherChannel distributes frames across the links in a 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.

EtherChannel frame distribution is based on a Cisco-proprietary hashing algorithm. The algorithm is deterministic; given the same addresses and session information, you always hash to the same port in the channel, preventing out-of-order packet delivery.

The address may be a source, a destination, or a combination of two IP addresses, two MAC addresses, or two TCP/UDP port numbers depending on the policy that is adopted through the ip, mac, session, and ip-vlan-session options of the set port channel all distribution command. See the "Configuring EtherChannel Load Balancing" section for detailed information.

Note The set port channel all distribution session command is supported on Supervisor Engine 2, Supervisor Engine 720, and Supervisor Engine 32 only. The set port channel all distribution ip-vlan-session command is supported on Supervisor Engine 720 and Supervisor Engine 32 only.

EtherChannel frame distribution is not configurable on all supervisor engines. Enter the show module command on a supervisor engine to determine if EtherChannel frame distribution is configurable on your switch. If the display shows the "Sub-Type" to be "L2 Switching Engine I WS-F6020," then EtherChannel frame distribution is not configurable on your Catalyst 6500 series switch; the switch uses source and destination Media Access Control (MAC) addresses.

EtherChannel frame distribution is configurable with all other switching engines. The default is to use source and destination IP addresses.

Port Aggregation Control Protocol and Link Aggregation Control Protocol

Port Aggregation Control Protocol (PAgP) and Link Aggregation Control Protocol (LACP) are two different protocols that allow ports with similar characteristics to form a channel through dynamic negotiation with adjoining switches. PAgP is a Cisco-proprietary protocol that can be run only on Cisco switches and those switches that are released by licensed vendors. LACP, which is defined in IEEE 802.3ad, allows Cisco switches to manage Ethernet channeling with devices that conform to the 802.3ad specification.

Note MAC address notification settings are ignored on PAgP and LACP EtherChannel ports.

To use PAgP, see the "Understanding How the Port Aggregation Protocol Works" section. To use LACP, see the "Understanding How the Link Aggregation Control Protocol Works" section.

EtherChannel Configuration Guidelines

If improperly configured, some EtherChannel ports are disabled automatically to avoid network loops and other problems.

Note Except where specifically differentiated, these guidelines apply to both PAgP and LACP.

These sections provide the guidelines for EtherChannel configuration:

•Port Configuration Guidelines

•VLAN and Trunk Configuration Guidelines

•Interaction with Other Features Guidelines

Port Configuration Guidelines

This section describes the guidelines for port configuration:

•You can have a maximum of eight compatibly configured ports per EtherChannel; the ports do not have to be contiguous or on the same module.

•All ports in an EtherChannel must be placed in the same administrative group. Enter the show channel group command to verify the administrative group, and enter the set port channel mod/ports admin_group command if necessary to assign ports to the same administrative group.

•All ports in an EtherChannel must use the same protocol; you cannot run two protocols on one module.

•PAgP and LACP are not compatible; both ends of a channel must use the same protocol.

Note You can configure the switch manually with PAgP on one side and LACP on the other side in the on mode.

•You can change the protocol at any time, but this change causes all existing EtherChannels to reset to the default channel mode for the new protocol.

•Configure all ports in an EtherChannel to operate at the same speed and duplex mode (full duplex only for LACP mode).

•Enable all ports in an EtherChannel. If you disable a port in an EtherChannel, it is treated as a link failure and its traffic is transferred to one of the remaining ports in the EtherChannel.

•A port cannot belong to more than one channel group at the same time.

•Ports with different port path costs, set by the set spantree portcost command, can form an EtherChannel as long as they are otherwise compatibly configured. Setting different port path costs does not, by itself, make ports incompatible for the formation of an EtherChannel.

•PAgP and LACP manage channels differently. When all the ports in a channel get disabled, PAgP removes them from its internal channels list; the show commands do not display the channel. With LACP, when all the ports in a channel get disabled, LACP does not remove the channel; the show commands continue to display the channel even though all its ports are down. To determine if a channel is actively sending and receiving traffic with LACP, enter the show port command to see if the link is up or down.

•LACP does not support half-duplex links. If a port is in active/passive mode and becomes half duplex, the port is suspended (and a syslog message is generated). The port is shown as "connected" when you enter the show port command and as "not connected" when you enter the show spantree command. This discrepancy occurs because the port is physically connected but never joined spanning tree. To get the port to join spanning tree, either set the duplex to full or set the channel mode to off for that port.

With software release 7.3(1) and later releases, the LACP behavior for the half-duplex links has changed and the affected ports are no longer suspended. Instead of suspending a port, the LACP PDU transmission (if any) is suppressed. If the port is part of a channel, the port is detached from the channel but still functions as a nonchannel port. A syslog message is generated when this condition occurs. The normal LACP behavior is reenabled automatically when you set the link to full duplex.

VLAN and Trunk Configuration Guidelines

This section describes the guidelines for VLAN and trunk-related configuration:

•Assign all ports in an EtherChannel to the same VLAN, or configure them as trunk ports.

•If you configure the EtherChannel as a trunk, configure the same trunk mode on all the ports in the EtherChannel. Configuring ports in an EtherChannel in different trunk modes can have unexpected results.

•An EtherChannel supports the same allowed range of VLANs on all the ports in a trunking EtherChannel. If the allowed range of VLANs is not the same for a port list, the ports do not form an EtherChannel even when set to the auto or desirable mode with the set port channel command.

•Do not configure the ports in an EtherChannel as dynamic VLAN ports. Doing so can adversely affect switch performance.

•Ports with different VLAN cost configurations cannot form a channel.

Interaction with Other Features Guidelines

This section describes the guidelines for the EtherChannel's interaction with other features:

•An EtherChannel does not form with ports that have different GARP VLAN Registration Protocol (GVRP), GARP Multicast Registration Protocol (GMRP), and QoS configurations.

•An EtherChannel does not form with ports when you enable port security. You cannot enable port security for ports in an EtherChannel.

•An EtherChannel does not form if one of the ports is a SPAN destination port.

•An EtherChannel does not form if protocol filtering is set differently on the ports.

•Cisco Discovery Protocol (CDP) runs on the physical port even after the port is added to a channel.

•VLAN Trunking Protocol (VTP) and Dual Ring Protocol (DRiP) run on the channel.

•During fast switchover to the standby supervisor engine, all channeling ports are cleared on the standby supervisor engine channeling configuration and state, and the links are pulled down temporarily to cause partner ports to reset. All ports are reset to the nonchanneling state.

•Ports with different dot1q port types cannot form a channel.

•Ports with different jumbo frame configurations cannot form a channel.

•Ports with different dynamic configurations cannot form a channel.

•During high-availability switchover to the standby supervisor engine, all channeling ports remain operational. Ports are reset only if there are events missing during the switchover.

Note With software release 6.3(1) and later releases, a PAgP-configured EtherChannel is preserved even if it contains only one port (this situation does not apply to LACP-configured EtherChannels). In software releases prior to 6.3(1), traffic was disrupted when you removed a 1-port channel from spanning tree and then added it to spanning tree as an individual port.

Note With software release 6.3(1) and later releases, due to the port ID handling by the spanning-tree feature, the maximum number of EtherChannels is 126 for a 6- or 9-slot chassis and 63 for a 13-slot chassis.

Understanding How the Port Aggregation Protocol Works

Note Use the information in these sections if you are configuring EtherChannel using PAgP. If you are using LACP, see the "Understanding How the Link Aggregation Control Protocol Works" section.

These sections describe PAgP:

•PAgP Modes

•PAgP Administrative Groups

•PAgP EtherChannel IDs

PAgP Modes

PAgP facilitates the automatic creation of EtherChannels by exchanging packets between Ethernet ports. PAgP packets are exchanged only between ports in auto and desirable modes. Ports that are configured in on or off mode do not exchange PAgP packets. The protocol learns the capabilities of port groups dynamically and informs the other ports. After PAgP identifies correctly matched EtherChannel links, it groups the ports into an EtherChannel. The EtherChannel is then added to the spanning tree as a single bridge port.

EtherChannel includes four user-configurable modes: on, off, auto, and desirable. Only auto and desirable are PAgP modes. You can modify the auto and desirable modes with the silent and non-silent keywords. By default, the ports are in auto silent mode.

Table 6-1 describes the EtherChannel modes that are available in PAgP.

Table 6-1 EtherChannel Modes Available in PAgP

Mode

Description

on

Mode that forces the port to channel without PAgP. With the on mode, a usable EtherChannel exists only when a port group in on mode is connected to another port group in on mode.

off

Mode that prevents the port from channeling.

auto

PAgP mode that places a port into a passive negotiating state in which the port responds to PAgP packets that it receives but does not initiate PAgP packet negotiation. (Default)

desirable

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

silent

Keyword that is used with the auto or desirable mode when no traffic is expected from the other device to prevent the link from being reported to the Spanning Tree Protocol as down. (Default)

non-silent

Keyword that is used with the auto or desirable mode when traffic is expected from the other device.

Both the auto and desirable modes allow ports to negotiate with connected ports to determine if they can form an EtherChannel, based on criteria such as port speed, trunking state, and VLAN numbers.

Ports can form an EtherChannel when they are in different PAgP modes as long as the modes are compatible, as follows:

•A port in desirable mode can form an EtherChannel with another port that is in desirable or auto mode.

•A port in auto mode can form an EtherChannel with another port in desirable mode.

•A port in auto mode cannot form an EtherChannel with another port that is also in auto mode, because neither port will initiate negotiation.

When configurable, EtherChannel frame distribution can use MAC addresses, IP addresses, and Layer 4 port numbers. You can specify either the source or the destination address or both the source and destination addresses and Layer 4 port numbers. The mode that you select applies to all EtherChannels that are configured on the switch. Use the option that provides the greatest variety in your configuration. For example, if the traffic on a channel is going to a single MAC address only, using source addresses, IP addresses, or Layer 4 port numbers for frame distribution may provide better frame distribution than selecting MAC addresses.

PAgP Administrative Groups

Configuring an EtherChannel creates an administrative group, which is designated by an integer between 1 and 1024, to which the EtherChannel belongs. When an administrative group is created, you can assign an administrative group number or let the next available administrative group number be assigned automatically. Forming a channel without specifying an administrative group number creates a new automatically numbered administrative group. An administrative group may contain a maximum of eight ports.

Enter the show channel group command to verify that all ports in an EtherChannel belong to the same administrative group, and enter the set port channel mod/ports admin_group command if necessary to assign ports to the same administrative group.

PAgP EtherChannel IDs

Each EtherChannel is automatically assigned a unique EtherChannel ID. Enter the show channel group admin_group command to display the EtherChannel ID.

Configuring an EtherChannel Using PAgP

These sections describe how to configure an EtherChannel using PAgP:

•Specifying the EtherChannel Protocol

•Configuring an EtherChannel

•Setting the EtherChannel Port Mode

•Setting the EtherChannel Port Path Cost

•Setting the EtherChannel VLAN Cost

•Configuring EtherChannel Load Balancing

•Displaying EtherChannel Traffic Utilization

•Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

•Disabling an EtherChannel

Note Before you configure the EtherChannel, see the "EtherChannel Configuration Guidelines" section.

Specifying the EtherChannel Protocol

Note The default protocol is PAgP.

Note You can specify only one protocol, PAgP or LACP, per module.

To specify the EtherChannel protocol, perform this task in privileged mode:

Task

Command

Specify the EtherChannel protocol.

set channelprotocol [pagp | lacp] mod

This example shows how to specify the PAgP protocol for module 3:
Console> (enable) set channelprotocol pagp 3
Channeling protocol set to PAGP for module(s) 3.
Console> (enable)
Configuring an EtherChannel

To configure an EtherChannel on a group of Ethernet ports, perform this task in privileged mode:

Task

Command

Configure an EtherChannel on the desired ports.

set port channel mod/ports... [admin_group]
set port channel mod/ports... mode
{on | off | desirable | auto} [silent | non-silent]

Enter the show channel group command to verify that all ports in the EtherChannel belong to the same administrative group, and enter the set port channel mod/ports admin_group command if necessary to assign ports to the same administrative group.

This example shows how to configure a seven-port EtherChannel in a new administrative group:
Console> (enable) set port channel 2/2-8 mode desirable
Ports 2/2-8 left admin_group 1.
Ports 2/2-8 joined admin_group 2.
Console> (enable)
Setting the EtherChannel Port Mode

To set a port's EtherChannel mode, perform this task in privileged mode:

Task

Command

Set a port's EtherChannel mode.

set port channel mod/ports... [admin_group]
set port channel mod/port mode
{on | off | desirable | auto} [silent | non-silent]

This example shows how to set port 2/1 to auto mode:
Console> (enable) set port channel 2/1 mode auto
Ports 2/1 channel mode set to auto.
Console> (enable)
Setting the EtherChannel Port Path Cost

Note You accomplish this task using a global command that configures both LACP and PAgP.

The channel path cost is achieved by adjusting the port costs of each port belonging to the channel. If you do not specify the cost, it is updated based on the current port costs of the channeling ports. You may address one channel or all channels.

To set the EtherChannel port path cost, perform this task in privileged mode:

Task

Command

Step 1

Use the administrative group number to display the EtherChannel ID.

show channel group admin_group

or

show lacp-channel group admin_key

Step 2

Use the EtherChannel ID to set the EtherChannel port path cost.

set spantree channelcost {channel_id | all} cost

Note When you enter the set spantree channelcost command, it does not appear in the configuration file. The command causes a "set spantree portcost" entry to be created for each port in the channel. See the "Configuring the PVST+ Port Cost" section in Chapter 7, "Configuring Spanning Tree," for information on using the set spantree portcost command.

This example shows how to set the EtherChannel port path cost for channel ID 768:
Console> (enable) show channel group 20
Admin Port  Status     Channel   Channel
group                  Mode      id
----- ----- ---------- --------- --------
  20    1/1 notconnect on             768
  20    1/2 connected  on             768
Admin Port  Device-ID                       Port-ID                   Platform
group
----- ----- ------------------------------- ------------------------- ----------
  20    1/1  
  20    1/2  066510644(cat26-lnf(NET25))     2/1                       WS-C6009
Console> (enable)
Console> (enable) set spantree channelcost 768 12
Port(s) 1/1,1/2 port path cost are updated to 31.
Channel 768 cost is set to 12.
Warning:channel cost may not be applicable if channel is broken.
Console> (enable)
Setting the EtherChannel VLAN Cost

Note You accomplish this task by using a global command that configures both LACP and PAgP.

The EtherChannel VLAN cost feature provides load balancing of VLAN traffic across multiple channels that are configured with trunking.

You enter the set spantree channelvlancost command to set the initial spanning-tree costs for all VLANs in the channel. The set spantree channelvlancost command provides an alternate cost for some of the VLANs in the channel (assuming that you are trunking across the channel). This command allows you to have up to two different spanning-tree costs assigned per channel; some VLANs in the channel can have the "vlancost" while the remaining VLANs in the channel have the "cost."

The set spantree channelvlancost command creates a "set spantree portvlancost" entry to the configuration file for each port in the channel. After you enter the set spantree channelvlancost command, you must enter the set spantree portvlancost command for at least one port in the channel, specifying the VLAN or VLANs that you want associated with each port. This example shows what occurs when you enter each command:
Console> (enable) set spantree channelvlancost 856 10 
Port(s) 3/47-48 vlan cost are updated to 16. 
Channel 856 vlancost is set to 10.
These commands are added to the configuration file:

•set spantree portvlancost 3/47 cost 16

•set spantree portvlancost 3/48 cost 16

To add the desired VLANs to the above created commands, enter this command:
Console> (enable) set spantree portvlancost 3/47 cost 16 1-1005 
Port 3/47 VLANs 1025-4094 have path cost 19. 
Port 3/47 VLANs 1-1005 have path cost 16. 
Port 3/48 VLANs 1-1005 have path cost 16. 
To set the EtherChannel VLAN cost, perform this task in privileged mode:

Task

Command

Step 1

Use the administrative group number to display the EtherChannel ID.

show channel group admin_group

or

show lacp-channel group admin_key

Step 2

Use the EtherChannel ID to set the EtherChannel VLAN cost.

set spantree channelvlancost channel_id cost

Step 3

Configure the port cost for the desired VLANs on each port.

set spantree portvlancost {mod/port} [cost cost] [vlan_list]

This example shows how to set the EtherChannel VLAN cost for channel ID 856:
Console> (enable) show channel group 22
Admin Port  Status     Channel   Channel
group                  Mode      id
----- ----- ---------- --------- --------
  22    1/1 notconnect on             856
  22    1/2 connected  on             856
Admin Port  Device-ID                       Port-ID                   Platform
group
----- ----- ------------------------------- ------------------------- ----------
  22    1/1  
  22    1/2  066510644(cat26-lnf(NET25))     2/1                       WS-C6009
Console> (enable)
Console> (enable) set spantree channelvlancost 856 10 
Port(s) 3/47-48 vlan cost are updated to 16. 
Channel 856 vlancost is set to 10.
Console> (enable) set spantree portvlancost 3/47 cost 16 1-1005 
Port 3/47 VLANs 1025-4094 have path cost 19. 
Port 3/47 VLANs 1-1005 have path cost 16. 
Port 3/48 VLANs 1-1005 have path cost 16. 
Console> (enable)
Configuring EtherChannel Load Balancing

The load-balancing policy (frame distribution) can be based on a MAC address (Layer 2), an IP address (Layer 3), or a port number (Layer 4). These policies can be activated, respectively, by the mac, ip, and session keywords. The load balancing can be based solely on the source address (source keyword), destination address (destination keyword), or both source and destination addresses (both keyword).

If a packet does not belong to a selected category, the next lower level category is considered. If the hardware cannot support the frame distribution method that is selected, a "Feature not supported" error message is displayed.

To configure EtherChannel load balancing, perform this task in privileged mode:

Task

Command

Configure EtherChannel load balancing.

set port channel all distribution {ip | mac | session | ip-vlan-session} [source | destination | both]

Note The set port channel all distribution session command option is supported on Supervisor Engine 2, Supervisor Engine 720, and Supervisor Engine 32 only.

Note The set port channel all distribution ip-vlan-session command is supported on Supervisor Engine 720 and Supervisor Engine 32 only. Use the command to specify the frame distribution method using the IP address, VLAN, and Layer 4 traffic.

This example shows how to configure EtherChannel to use MAC source addresses:
Console> (enable) set port channel all distribution mac source
Channel distribution is set to mac source.
Console> (enable)
Displaying EtherChannel Traffic Utilization

To display the traffic utilization on the EtherChannel ports, perform this task:

Task

Command

Display traffic utilization.

show channel traffic

This example shows how to display traffic utilization on EtherChannel ports:
Console> (enable) show channel traffic
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   808  2/16   0.00%   0.00%  50.00%  75.75%   0.00%   0.00%
   808  2/17   0.00%   0.00%  50.00%  25.25%   0.00%   0.00%
   816  2/31   0.00%   0.00%  25.25%  50.50%   0.00%   0.00%
   816  2/32   0.00%   0.00%  75.75%  50.50%   0.00%   0.00%
Console> (enable)
Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

To display the outgoing port that is used in an EtherChannel for a specific address or Layer 4 port number, perform this task:

Task

Command

Display the outgoing port for a specified address or Layer 4 port number.

show channel hash channel_id src_ip_addr vlan src_port [dest_ip_addr vlan dest_port]

show channel hash channel_id dest_ip_addr vlan dest_port

This example shows how to display the outgoing port for the specified source and destination IP addresses:
Console> (enable) show channel hash 808 172.20.32.10 172.20.32.66
Selected channel port:2/17
Console> (enable)
Disabling an EtherChannel

To disable an EtherChannel, perform this task in privileged mode:

Task

Command

Disable an EtherChannel.

set port channel mod/port mode off

This example shows how to disable an EtherChannel:
Console> (enable) set port channel 2/2-8 mode off
Ports 2/2-8 channel mode set to off.
Console> (enable)
Understanding How the Link Aggregation Control Protocol Works

Note Use the information in these sections if you are configuring EtherChannel using LACP. If you are using PAgP, see the "Understanding How the Port Aggregation Protocol Works" section.

This section contains the following descriptions:

•LACP Modes

•LACP Parameters

LACP Modes

You may manually turn on channeling by setting the port channel mode to on, and you may turn off channeling by setting the port channel mode to off.

If you want LACP to handle channeling, use the active and passive channel modes. To start automatic EtherChannel configuration with LACP, you need to configure at least one end of the link to active mode to initiate channeling, because ports in passive mode passively respond to initiation and never initiate the sending of LACP packets.

Table 6-2 describes the EtherChannel modes that are available in LACP.

Table 6-2 EtherChannel Modes Available in LACP

Mode

Description

on

Mode that forces the port to channel without LACP. With the on mode, a usable EtherChannel exists only when a port group in on mode is connected to another port group in on mode.

off

Mode that prevents the port from channeling.

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 packet negotiation. (Default)

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.

LACP Parameters

The parameters that are used in configuring LACP are as follows:

•System priority

You must assign a system priority that can be specified automatically or through the CLI (see the "Specifying the System Priority" section) to each switch running LACP. The system priority is used with the switch MAC address to form the system ID and is also used during negotiation with other systems.

•Port priority

You must assign a port priority that can be specified automatically or through the CLI (see the "Specifying the Port Priority" section) to each port in the switch. The port priority is used with the port number to form the port identifier. The port priority is used to decide which ports should be put in standby mode when there is a hardware limitation that prevents all compatible ports from aggregating.

•Administrative key

You must assign an administrative key value that can be specified automatically or through the CLI to each port in the switch (see the "Specifying an Administrative Key Value" section). The ability of a port to aggregate with other ports is defined with the administrative key. A port's ability to aggregate with other ports is determined by these factors:

–Port physical characteristics, such as data rate, duplex capability, and point-to-point or shared medium

–Configuration constraints that you establish

When enabled, LACP always tries to configure the maximum number of compatible ports in a channel, up to the maximum that is allowed by the hardware (eight ports). If LACP is not able to aggregate all the ports that are compatible (for example, the remote system might have more restrictive hardware limitations), then all the ports that cannot be actively included in the channel are put in hot standby state and are used only if one of the channeled ports fails.

You can configure different channels with ports that have been assigned the same administrative key. For example, if eight ports are assigned the same administrative key, you may configure four ports in a channel using LACP active mode and the remaining four ports in a manually configured channel using the on mode. An administrative key is meaningful only in the context of the switch that allocates it; there is no global significance to administrative key values.

Configuring an EtherChannel Using LACP

These sections describe how to configure EtherChannel using LACP:

•Specifying the EtherChannel Protocol

•Specifying the System Priority

•Specifying the Port Priority

•Specifying an Administrative Key Value

•Changing the Channel Mode

•Specifying the Channel Path Cost

•Specifying the Channel VLAN Cost

•Configuring Channel Load Balancing

•Clearing the LACP Statistics

•Displaying EtherChannel Traffic Utilization

•Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

•Disabling an EtherChannel

•Displaying the Spanning-Tree Information for EtherChannels

Note Before you configure the EtherChannel, see the "EtherChannel Configuration Guidelines" section.

Specifying the EtherChannel Protocol

Note The default protocol is PAgP.

Note You can specify only one protocol, PAgP or LACP, per module.

To specify the EtherChannel protocol, perform this task in privileged mode:

Task

Command

Specify the EtherChannel protocol.

set channelprotocol [pagp | lacp] mod

This example shows how to specify the LACP protocol for modules 2 and 3:
Console> (enable) set channelprotocol lacp 2,3
Mod 2 is set to LACP protocol.
Mod 3 is set to LACP protocol.
Console> (enable)
Use the show channelprotocol command to display the protocols for all modules.

Specifying the System Priority

Note Although this command is a global option, the command applies only to modules on which LACP is enabled; it is ignored on modules running PAgP.

The system priority value must be a number in the range of 1-65535, where higher numbers represent lower priority. The default priority is 32768.

To specify the system priority, perform this task in privileged mode:

Task

Command

Specify the system priority.

set lacp-channel system-priority value

This example shows how to specify the system priority as 20000:
Console> (enable) set lacp-channel system-priority 20000
LACP system priority is set to 20000
Console> (enable)
Use the show lacp-channel sys-id command to display the LACP system ID and system priority.

Specifying the Port Priority

The port priority value must be a number in the range of 1-255, where higher numbers represent lower priority. The default priority is 128.

To specify the port priority, perform this task in privileged mode:

Task

Command

Specify the port priority.

set port lacp-channel mod/ports port-priority value

This example shows how to specify the port priority as 10 for ports 1/1 to 1/4 and 2/6 to 2/8:
Console> (enable) set port lacp-channel 1/1-4,2/6-8 port-priority 10
Port(s) 1/1-4,2/6-8 port-priority set to 10.
Console> (enable) 
Use the show lacp-channel group admin_key info command to display the port priority.

Specifying an Administrative Key Value

Note When the system or module configuration information that is stored in NVRAM is cleared, the administrative keys are assigned new values automatically. For modules, each group of four consecutive ports, beginning at the 1st, 5th, 9th and so on, are assigned a unique administrative key. Across the module, ports must have unique administrative keys. After NVRAM is cleared, the channel mode of the ports is set to "passive."

You can specify an administrative key value to a set of ports or the system automatically selects a value if you do not specify the parameter admin_key. In both cases, the admin_key value can range from
1-1024.

If you choose a value for the administrative key, and this value has already been used in the system, then all the ports that were originally associated with the previously assigned admin_key value are moved to another automatically assigned value, and the modules and ports that you specified in the command are assigned the admin_key value that you specified.

The maximum number of ports to which an administrative key can be assigned is eight.

The default mode for all ports being assigned the administrative key is passive. However, if the channel was previously assigned a particular mode (see the "Changing the Channel Mode" section), assigning the administrative key will not affect it, and the channel mode that you specified previously is maintained.

To specify the administrative key value, perform this task in privileged mode:

Task

Command

Specify the administrative key value.

set port lacp-channel mod/ports [admin_key]

This example shows how to assign the same administrative key to ports 4/1 to 4/4, with the system picking its value automatically:
Console> (enable) set port lacp-channel 4/1-4
Port(s) 4/1-4 are assigned to admin key 96.
Console> (enable)
This example shows how to assign the administrative key 96 (you specify the 96) to ports 4/4 to 4/6. In this example, the administrative key was previously assigned to another group of ports by the system (see the previous example):
Console> (enable) set port lacp-channel 4/4-6 96
Port(s) 4/1-3 are moved to admin key 97.
Port(s) 4/4-6 are assigned to admin key 96.
Console> (enable)
This example shows the system response when more than eight ports are assigned the same administrative key value (the request is denied, and no ports are assigned administrative key 123):
Console> (enable) set port lacp-port channel 2/1-2,4/1-8 123
No more than 8 ports can be assigned to an admin key.
Console> (enable)
Enter the show lacp-channel group command to display administrative key values for ports, and to verify that all ports in an EtherChannel share the same administrative key value. Enter the set port lacp-channel mod/ports admin_key command if necessary to assign all EtherChannel ports to the same administrative key.

Changing the Channel Mode

You can change the channel mode for a set of ports that were previously assigned the same administrative key (see the "Specifying an Administrative Key Value" section).

To change the channel mode, perform this task in privileged mode:

Task

Command

Change the channel mode.

set port lacp-channel mod/ports mode [on | off | active | passive]

This example shows how to change the channel mode for ports 4/1 and 4/6, setting it to on. The administrative key for ports 4/1 and 4/6 is unchanged.
Console> (enable) set port lacp-channel 4/1,4/6 mode on
Port(s) 4/1,4/6 channel mode set to on.
Console> (enable)
Use the show lacp-channel group admin_key command to display the channel mode for ports.

Specifying the Channel Path Cost

You can specify the channel path cost by using a global command that configures both LACP and PAgP. For more information, see the "Setting the EtherChannel Port Path Cost" section.

Specifying the Channel VLAN Cost

You can specify the channel VLAN cost by using a global command that configures both LACP and PAgP. For more information, see the "Setting the EtherChannel VLAN Cost" section.

Configuring Channel Load Balancing

You can configure channel load balancing by using a global command that configures both LACP and PAgP. For more information, see the "Configuring EtherChannel Load Balancing" section.

Clearing the LACP Statistics

To clear the LACP statistics, perform this task in privileged mode:

Task

Command

Clear LACP statistics.

clear lacp-channel statistics

This example shows how to clear LACP statistics:
Console> (enable) clear lacp-channel statistics
LACP channel counters are cleared. 
Console> (enable)
Displaying EtherChannel Traffic Utilization

To display the traffic utilization on the EtherChannel ports, perform this task:

Task

Command

Display traffic utilization on the EtherChannel ports.

show lacp-channel traffic

This example shows how to display traffic utilization on the EtherChannel ports:
Console> (enable) show lacp-channel traffic
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   808  2/16   0.00%   0.00%  50.00%  75.75%   0.00%   0.00%
   808  2/17   0.00%   0.00%  50.00%  25.25%   0.00%   0.00%
   816  2/31   0.00%   0.00%  25.25%  50.50%   0.00%   0.00%
   816  2/32   0.00%   0.00%  75.75%  50.50%   0.00%   0.00%
Console> (enable)
Displaying the Outgoing Ports for a Specified Address or Layer 4 Port Number

To display the outgoing port that is used in an EtherChannel for a specified address or Layer 4 port number, perform this task:

Task

Command

Display the outgoing port for a specified address or Layer 4 port number.

show lacp-channel hash channel_id src_ip_addr [dest_ip_addr] | dest_ip_address | src_mac_addr [dest_mac_addr] | dest_mac_addr | src_port dest_port | dest_port

This example shows how to display the outgoing port for the specified source and destination IP addresses:
Console> (enable) show lacp-channel hash 808 172.20.32.10 172.20.32.66
Selected channel port:2/17
Console> (enable)
Disabling an EtherChannel

To disable an EtherChannel, perform this task in privileged mode:

Task

Command

Disable an EtherChannel.

set port lacp-channel mod/port mode off

This example shows how to disable an EtherChannel:
Console> (enable) set port lacp-channel 2/2-8 mode off
Port(s) 2/2-8 channel mode set to off.
Console> (enable)
Displaying the Spanning-Tree Information for EtherChannels

You can display the channel ID and the truncated port list for all ports that are channeling. The ports that are not channeling are identified by their port number.

To display the spanning-tree information for EtherChannels, perform this task:

Task

Command

Display the spanning-tree information for EtherChannels.

show spantree mod/port

These examples show how to display the spanning-tree information for EtherChannels:
Console> show spantree 4/6
Port                     Vlan Port-State    Cost  Priority Portfast   Channel_id
------------------------ ---- ------------- ----- -------- ---------- ----------
 4/6                     1    not-connected     4       32 disabled   0         
Console>
Console> show spantree 4/7
Port                     Vlan Port-State    Cost  Priority Portfast   Channel_id
------------------------ ---- ------------- ----- -------- ---------- ----------
4/7-8                    1    blocking          3       32 disabled   770       
Console>
Clearing and Restoring the EtherChannel Counters

The show channel traffic command allows you to display the channel traffic utilization. The channel traffic utilization shows the percentage of traffic that passes through each channel port. The counters are maintained for different types of packets. Before software release 8.3(1), you could not clear the channel hardware counter bases because the bases are MIB objects that do not clear. Enter the clear counters all command to reset the channel counter bases. With software release 8.3(1) and later releases, you can clear and restore the channel-based counters on a per-protocol and per-channel basis. To clear or restore the channel-based counters on a per-channel basis, enter the channel ID. To find the channel ID, enter the show port channel command for the PAgP channels or the show port lacp-channel command for the LACP channels.

Clearing the EtherChannel Counters

To clear the EtherChannel counters, perform these tasks in privileged mode:

Task

Command

Clear all PAgP channel counters.

clear counter channel all

Clear a specific PAgP channel counter.

clear counter channel channel_id

Clear all LACP channel counters.

clear counter lacp-channel all

Clear a specific LACP channel counter.

clear counter lacp-channel channel_id

These examples show the various methods of clearing the EtherChannel counters:
Console> (enable) show channel traffic
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   769  1/1    0.00%   0.00%   9.09%  90.90%   0.00%   0.00%
   769  2/1    0.00%   0.00%  90.91%   9.10%   0.00%   0.00%
------ ----- ------- ------- ------- ------- ------- -------
   841  7/17   0.00%   0.00% 100.00% 100.00%   0.00%   0.00%
   841  7/18   0.00%   0.00%   0.00%   0.00%   0.00%   0.00%
Console> (enable) clear counter channel all
This command will reset MAC and port counters reported by the CLI for all ports.
Counters reported by SNMP will not be affected.
Do you want to continue (y/n) [n]? y
MAC and Port counters cleared.
Console> (enable) show channel traffic     
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   769  1/1    0.00%   0.00%   0.00% 100.00%   0.00%   0.00%
   769  2/1    0.00%   0.00% 100.00%   0.00%   0.00%   0.00%
------ ----- ------- ------- ------- ------- ------- -------
   841  7/17   0.00%   0.00% 100.00% 100.00%   0.00%   0.00%
   841  7/18   0.00%   0.00%   0.00%   0.00%   0.00%   0.00%
Console> (enable) show channel traffic 769
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   769  1/1    0.00%   0.00%   9.52%  90.47%   0.00%   0.00%
   769  2/1    0.00%   0.00%  90.48%   9.53%   0.00%   0.00%
Console> (enable) clear counter channel 769
This command will reset MAC and port counters reported by the CLI for PAGP channel 769
Counters reported by SNMP will not be affected.
Do you want to continue (y/n) [n]? y
MAC and Port counters cleared.
Console> (enable) show channel traffic 769 
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   769  1/1    0.00%   0.00%   0.00% 100.00%   0.00%   0.00%
   769  2/1    0.00%   0.00% 100.00%   0.00%   0.00%   0.00%
Console> (enable)
Restoring the EtherChannel Counters

To restore the EtherChannel counters, perform these tasks in privileged mode:

Task

Command

Restore all PAgP channel counters.

restore counter channel all

Restore a specific PAgP channel counter.

restore counter channel channel_id

Restore all LACP channel counters.

restore counter lacp-channel all

Restore a specific LACP channel counter.

restore counter lacp-channel channel_id

This example shows how to restore the counters for channel 769:
Console> (enable) restore counter channel 769
This command will restore counter values reported by the CLI
for PAGP channel 769 ports to the hardware counter values.
Do you want to continue (y/n) [n]? y
MAC and Port counters restored.
Console> (enable) show channel traffic 769   
ChanId Port  Rx-Ucst Tx-Ucst Rx-Mcst Tx-Mcst Rx-Bcst Tx-Bcst
------ ----- ------- ------- ------- ------- ------- -------
   769  1/1    0.00%   0.00%   7.69%  92.30%   0.00%   0.00%
   769  2/1    0.00%   0.00%  92.31%   7.70%   0.00%   0.00%
Console> (enable) 