Link Aggregation Group (LAG)

Link Aggregation Group (LAG) protocol describes a network operation in which several same speed links are combined into a single logical entity with the accumulated bandwidth of the originating ports. LAG groups exchange Lag Aggregation Control Protocol (LACP) packets in order to align the functionality between both endpoints of the LAG. To equally send traffic on all LAG links, the switch uses a hash function which can use a set of attributes as key to the hash function.

As many as 32 physical ports can be aggregated on a single LAG.

Configuring Static LAG

Create a port-channel entity.

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

Change back to config mode.

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            switch (config interface port-channel 1) # exit
switch (config) #

Add a physical port to the LAG.
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```
            
            switch (config interface ethernet 1/4) # channel-group 1 mode on
switch (config interface ethernet 1/4) # 
        
```
Warning

If the physical port is operationally up, this port becomes an active member of the aggregation. Consequently, it becomes able to convey traffic.

Configuring Link Aggregation Control Protocol (LACP)

Create a port-channel entity.

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

Change back to config mode.

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            switch (config interface port-channel 1) # exit
switch (config) #

Enable LACP in the switch.

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            switch (config) # lacp

Add a physical port to the LAG.

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            switch (config interface ethernet 1/4) # channel-group 1 mode active

Or:

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            switch (config interface ethernet 1/4) # channel-group 1 mode passive

Additional Reading and Use Cases

For more information about this feature and its potential applications, please refer to the following community posts:

HowTo Configure LACP

LAG Commands

interface port-channel

	interface port-channel <1-4096>[-<2-4096>] no interface port-channel <1-4096>[-<2-4096>] Creates a LAG and enters the LAG configuration mode. There is an option to create a range of LAG interfaces. The no form of the command deletes the LAG, or range of LAGs.
Syntax Description	1-4096 / 2-4096	LAG number
Default	N/A
Configuration Mode	config
History	3.1.1400
History	3.2.1100	Added range support
Example	switch (config)# interface port-channel 1 switch (config interface port-channel 1) # exit switch (config)# interface port-channel 1-10 switch (config interface port-channel 1-10) #
Related Commands	show interface port-channel
Notes	If a LAG is also an IPL, attempting to delete it without first deleting the IPL is rejected by the management LAGs have forwarding mode in accordance with the global configuration

lacp

	lacp no lacp Enables LACP in the switch. The no form of the command disables LACP in the switch.
Syntax Description	N/A
Default	LACP is disabled
Configuration Mode	config
History	3.1.1400
Example	switch (config)# lacp
Related Commands
Notes

lacp system-priority

	lacp system-priority <1-65535> no lacp system-priority Configures the LACP system priority. The no form of the command sets the LACP system-priority to default.
Syntax Description	1-65535	LACP system-priority
Default	32768
Configuration Mode	config
History	3.1.1400
Example	switch (config)# lacp system-priority 1
Related Commands	show lacp interfaces port-channel
Notes	Each device that runs LACP has an LACP system priority value. A value between 1 and 65535 can be configured. LACP uses the system priority with the MAC address to form the system ID. When setting the priority, a higher number means a lower priority.

lacp (interface)

	lacp {rate fast \| port-priority <1-65535>} no lacp {rate fast \| port-priority} Configures the LACP interface parameters. The no form of the command sets the LACP interface configuration to default.
Syntax Description	rate fast	Sets LACP PDUs on the port to be in fast (1 second) or slow rate (30 seconds)
Syntax Description	1-65535	LACP port-priority
Default	rate—slow (30 seconds) port-priority—32768
Configuration Mode	config interfaces ethernet
History	3.1.1400
Example	switch (config interfaces ethernet 1/7)# lacp rate fast
Related Commands
Notes	Configuring LACP rate (fast or slow) will configure the peer port to send (fast or slow), it does not make any affect on the local port LACP rate.

port-channel load-balance ethernet

	port-channel load-balance ethernet {<method> \| [symmetric]} no port-channel load-balance ethernet {<method> \| [symmetric]} Configures the port-channel load balancing distribution function method, with symmetric hashing enabled or not. The no form of the command sets the distribution function method to default, or disabling symmetric hashing.
Syntax Description	method	destination-ip	Destination IP address
		destination-mac	Destination MAC address
		destination-port	Destination UDP/TCP port
		flow-label	IPv6 flow-label field
		l2-protocol	Ethertype field
		l3-protocol	IP protocol field
		ingress-port	Ingress port
		source-destination-ip	Source and destination IP addresses
		source-destination-mac	Source and destination MAC addresses
		source-destination-port	Source and destination UDP/TCP ports
		source-ip	Source IP address
		source-mac	Source MAC address
		source-port	Source UDP/TCP port
		symmetric	Symmetric hashing; bidirectional flows follow same path
	symmetric	Enables symmetric hashing
Default	source-destination-mac, source-destination-ip, source-destination-port, l3-protocol, l2-protocol, flow-label
Configuration Mode	config
History	3.1.1400
	3.8.1000	Updated syntax
	3.8.2100	Changed the method options. Modified default LAG HASH to support TCP/UDP ports.
Example	switch (config) # port-channel load-balance ethernet ? destination-ip Destination IP address destination-mac Destination MAC address destination-port Destination UDP/TCP port flow-label IPv6 flow-label field l2-protocol Ethertype field l3-protocol IP protocol field ingress-port Ingress port source-destination-ip Source and destination IP addresses source-destination-mac Source and destination MAC addresses source-destination-port Source and destination UDP/TCP ports source-ip Source IP address source-mac Source MAC address source-port Source UDP/TCP port symmetric Symmetric hashing; bidirectional flows follow same path
Related Commands	show interface port-channel load-balance
Notes	As of 3.8.2100, the default value of port-channel load-balance has been changed from "source-destination-mac" to "source-destination-mac, source-destination-ip, source-destination-port, l3-protocol, l2-protocol, flow-label". This occurs only upon fresh installations or after "reset factory". Upgrading users will retain the old load balancing value and show running-config will indicate this. Several load balance methods can be configured (refer to the example) "ingress-port" and "symmetric" cannot both be set at the same time. The command will be rejected under the following conditions: 1) "ingress-port" and "symmetric" both appear in the same command. 2) "ingress-port" is requested while "symmetric" is in force from a previous command. It needs to be cancelled first with "no port-channel load-balance ethernet symmetric". 3)"symmetric" is requested BY ITSELF while "ingress-port" is in force from a previous command. If "symmetric" is part of a larger list that does not include "ingress-port", the meaning is to exclude "ingress-port" and the command will be accepted. When symmetric is set without other methods: only symmetric hashing can be set while other methods remain unchanged When symmetric is set together with other methods: symmetric hashing is set in parallel with other methods When other methods are set without symmetric: other methods are set, while symmetric hashing remains unchanged

channel-group

	channel-group <1-4096> [mode {on \| active \| passive}] no channel-group Assigns and configures a physical interface to a LAG. The no form of the command removes a physical interface from the port-channel.
Syntax Description	1-4096	The port channel number
	mode on	Static assignment the port to LAG. LACP will not be enabled on this port.
	mode active/passive	Dynamic assignment of the port to LAG. LACP will be enabled in either passive or active mode.
Default	N/A
Configuration Mode	config interface ethernet
History	3.1.1400
	3.4.0008	Added a note
	3.6.3640	Added a note
	3.6.4006	Added a note
Example	switch (config interface ethernet 1/7) # channel-group 1 mode active
Related Commands	show interfaces port-channel summary show interfaces port-channel compatibility-parameters show lacp interfaces ethernet
Notes	Setting the mode to active/passive is possible only in LACP is enabled The first port in the LAG decide if the LAG will be static (“on”) or LACP (“active” , “pasive”) All the ports in the LAG must have the same configuration, determines by the first port added to the LAG. The port with a different configuration will be rejected, for the list of dependencies refer to “show interfaces port-channel compatibility-parameters”. A physical port may only be part of one channel-group Added support to check if the forwarding mode of the interface is the same as the forwarding mode of LAG. Error output: % Channel-group and Ethernet port have different port forwarding mode configuration Port cannot be added to port-channel when storm-control is configured on port. Error output: % Interface has storm control configuration and can't be added to LAG*

lacp-individual enable

	lacp-individual enable [force] no lacp-individual enable [force] Configures the LAG to act with LACP-individual capabilities. The no form of the command disables the LACP-individual capability.
Syntax Description	force	Toggles the interface after enabling LACP-individual
Default	N/A
Configuration Mode	config interface port-channel
History	3.4.1100
Example	switch (config interface port-channel 10) # lacp-individual enable force
Related Commands
Notes	If a switch is connected via LAG to a host without LACP capability, running this command on that LAG allows a member port (with the lowest numerical priority value), acting as an individual, to communicate with the host

ip address dhcp

	ip address dhcp no ip address dhcp Enables DHCP on this LAG interface. The no form of the command disables DHCP on this LAG interface.
Syntax Description	N/A
Default	Disabled
Configuration Mode	config interface port-channel set as router interface
History	3.4.2008
Example	switch (config interface port channel 10) # ip address dhcp
Related Commands	interface port-channel show interface port-channel
Notes

show lacp counters

	show lacp counters Displays the LACP PDUs counters.
Syntax Description	N/A
Default	N/A
Configuration Mode	config interface port-channel set as router interface
History	3.1.1400
History	3.6.6000	Updated example
Example
switch (config) # show lacp counters VRF Name: default Port-channel 5: ----------------------------------------------------------------------------------- LACPDUs Marker Marker Marker Rsp Marker Rsp LACPDUs LACPDUs Illegal Unknown Port Sent Recv Sent Recv Sent Recv ----------------------------------------------------------------------------------- 1/12 0 0 0 0 0 0 0 0 1/11 0 0 0 0 0 0 0 0 1/10 0 0 0 0 0 0 0 0
Related Commands	interface port-channel show interface port-channel
Notes

show lacp interfaces ethernet

	show lacp interface ethernet <inf> Displays the LACP interface configuration and status.
Syntax Description	inf	Interface number (e.g., “1/1”)
Default	N/A
Configuration Mode	Any command mode
History	3.1.1400
History	3.6.6102	Updated example
Example
switch (config) # show lacp interfaces ethernet 1/1 Port: 1/1 Port State: Down Channel Group: 1 Pseudo port-channel: Po1 LACP port-priority: 32768 LACP Rate: Slow LACP Activity: Active LACP Timeout: Short Aggregation State: Aggregation, Defaulted, ------------------------------------------------------------- LACP Port Admin Oper Port Port Port State Priority Key Key Number State ------------------------------------------------------------- 1/1 Down 32768 13826 13826 0x1 0x0
Related Commands
Notes

show lacp interfaces neighbor

	show lacp interfaces neighbor Displays the LACP interface neighbor status.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.1.1400
History	3.4.0000	Updated example
Example
switch (config) # show lacp interfaces neighbor Flags: A - Device is in Active mode P - Device is in Passive mode Channel group 1 neighbors Port 1/4 ---------- Partner System ID : 00:00:00:00:00:00 Flags : A LACP Partner Port Priority : 0 LACP Partner Oper Key : 0 LACP Partner Port State : 0x0 Port State Flags Decode ------------------------ Activity : Active Aggregation State : Aggregation, Sync, Collecting, Distributing MLAG channel group 25 neighbors Port 1/49 ---------- Partner System ID : 00:02:c9:fa:c4:c0 Flags : A LACP Partner Port Priority : 255 LACP Partner Oper Key : 33 LACP Partner Port State : 0xbc Port State Flags Decode ------------------------ Activity : Active Aggregation State : Aggregation, Sync, Collecting, Distributing, MLAG channel group 28 neighbors Port 1/51 ---------- Partner System ID : f4:52:14:10:d8:f1 Flags : A LACP Partner Port Priority : 255 LACP Partner Oper Key : 33 LACP Partner Port State : 0xbc Port State Flags Decode ------------------------ Activity : Active Aggregation State : Aggregation, Sync, Collecting, Distributing,
Related Commands
Notes

show lacp

	show lacp Displays the LACP global parameters.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.4.0000
Example	switch (config) # show lacp Port-channel Module Admin Status is enabled
Related Commands
Notes

show lacp interfaces system-identifier

	show lacp interfaces {mlag-port-channel \| port-channel} <instance> system-identifier Displays the system identifier of LACP.
Syntax Description	instance	LAG or MLAG instance
Default	N/A
Configuration Mode	Any command mode
History	3.4.0000
Example	switch (config)# show lacp interfaces port-channel 2 system-identifier Priority: 12345 MAC: 00:02:c9:ac:2a:60
Related Commands
Notes

show interfaces port-channel

	show interfaces port-channel <port-channel> Displays LAG configuration properties.
Syntax Description	port-channel	LAG interface whose properties to display
Default	N/A
Configuration Mode	Any command mode
History	3.3.4000
	3.4.1100	Updated example
	3.6.1002	Added “error packets” counter to Tx
	3.6.5000	Updated example with telemetry
	3.6.8008	Updated example
	3.7.1000	Updated example
	3.9.1000	Updated example
Example
switch (config) # show interfaces port-channel 10 Po10: Admin state : Enabled Operational state : Down Description : N/A Mac address : N/A MTU : 1500 bytes (Maximum packet size 1522 bytes) lacp-individual mode: Disabled Flow-control : receive off send off Actual speed : N/A Width reduction mode: Not supported Switchport mode : access MAC learning mode : Enabled Forwarding mode : inherited cut-through FCS Ingress : Enabled CRC check FCS Egress : Disabled CRC recalculate FCS Timestamping : Enabled Telemetry sampling: Disabled TCs: N/A Telemetry threshold: Disabled TCs: N/A Telemetry threshold level: N/A Last clearing of "show interface" counters: Never 60 seconds ingress rate : 0 bits/sec, 0 bytes/sec, 0 packets/sec 60 seconds egress rate : 0 bits/sec, 0 bytes/sec, 0 packets/sec Rx: 0 packets 0 unicast packets 0 multicast packets 0 broadcast packets 0 bytes 0 discard packets 0 error packets 0 fcs errors 0 undersize packets 0 oversize packets 0 pause packets 0 unknown control opcode 0 symbol errors 0 discard packets by storm control Tx: 0 packets 0 unicast packets 0 multicast packets 0 broadcast packets 0 bytes 0 discard packets 0 error packets 0 hoq discard packets
Related Commands
Notes

show interfaces port-channel counters

	show interfaces port-channel <port-channel> counters Displays the extended counters for the interface.
Syntax Description	port-channel	LAG interface whose properties to display.
Default	N/A
Configuration Mode	Any command mode
History	3.6.1002
History	3.9.1000	Added ability to use a range of ports
Example	switch (config) # show interfaces port-channel 2-3 counters Po2: Rx: 0 packets 0 unicast packets 0 multicast packets 0 broadcast packets 0 bytes 0 packets of 64 bytes 0 packets of 65-127 bytes 0 packets of 128-255 bytes 0 packets of 256-511 bytes 0 packets of 512-1023 bytes 0 packets of 1024-1518 bytes 0 packets Jumbo 0 error packets 0 discard packets 0 fcs errors 0 undersize packets 0 oversize packets 0 pause packets 0 unknown control opcode 0 symbol errors Tx 1000000 packets 0 unicast packets 1000000 multicast packets 0 broadcast packets 1505000000 bytes 1000000 error packets 0 discard packets 0 pause packets 0 ECN marked packets Po3: . . .
Related Commands
Notes	As of version 3.9.1000, the "port-channel" attribute is optional. If nothing is selected, information for all ports will be displayed

show interfaces port-channel compatibility-parameters

	show interfaces port-channel compatibility-parameters Displays LAG parameters.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.3.4000
	3.6.3640	Added “forwarding mode” as compatibility parameter to output
	3.6.6000	Updated example
	3.6.8008	Updated example
Example	switch (config) # show interfaces port-channel compatibility-parameters Compatibility-parameters: * Port-mode * Speed * MTU * Forwarding mode * Flow Control * Access VLAN * Allowed VLAN list * Flowcontrol & PFC * Channel-group mode * QoS parameters * MAC learning disable Static configuration on the port should be removed: * ACL port binding * Static mrouter * sflow * OpenFlow * port mirroring local analyzer port * Static mac address
Related Commands
Notes

show interfaces port-channel load-balance

	show interfaces port-channel load-balance Displays the type of load-balancing in use for LAGs.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.3.4000
Example	switch (config) # show interfaces port-channel load-balance source-destination-mac
Related Commands	port-channel load-balance ethernet ?
Notes

show interfaces port-channel summary

	show interfaces port-channel summary Displays a summary for LAG interfaces.
Syntax Description	N/A
Default	N/A
Configuration Mode	Any command mode
History	3.1.1400
History	3.4.1100	Updated example
Example
switch (config) # show interfaces port-channel summary Flags: D - Down, U - Up, P - Up in port-channel (members) S - Suspend in port-channel (members), I - Individual ----------------------------------------------------------------------- Group Port- Type Member Ports Channel ----------------------------------------------------------------------- 1 Po2(U) LACP Eth1/58(D) Eth1/59(I) Eth1/60(S) 2 Po5(D) LACP Eth1/1(S) Eth1/33(I) 3 Po10(U) LACP Eth1/49(P) Eth1/50(P) Eth1/51(S) Eth1/52(S)
Related Commands
Notes

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