Device	Interface	IP address	Remarks
Device A	XGE 3/0/4	N/A	Device C: XGE 3/0/4 The interface is used as the M-LAG interface.
	XGE 3/0/5	N/A	Device ID: XGE 3/0/4 The interface is used as the M-LAG interface
	XGE 3/0/1	21.1.1.1/24	Device B: XGE 3/0/1 The interface is used as the keepalive interface.
	XGE 3/0/2	N/A	Device B: XGE 3/0/2 The interface is used as the peer-link interface.
	XGE 3/0/3	N/A	Device B: XGE 3/0/3 The interface is used as the peer-link interface.
Device B	XGE 3/0/4	N/A	Device C: XGE 3/0/5 The interface is used as the M-LAG interface
	XGE 3/0/5	N/A	Device ID: XGE 3/0/5 The interface is used as the M-LAG interface
	XGE 3/0/1	21.1.1.2/24	Device A: XGE 3/0/1 The interface is used as the keepalive interface.
	XGE 3/0/2	N/A	Device A: XGE 3/0/2 The interface is used as the peer-link interface.
	XGE 3/0/3	N/A	Device A: XGE 3/0/3 The interface is used as the peer-link interface.
Device C	XGE 3/0/4	N/A	Device A: XGE 3/0/4
	XGE 3/0/5	N/A	Device B: XGE 3/0/4
	XGE 3/0/1	N/A	Device E: XGE 3/0/1
Device D	XGE 3/0/4	N/A	Device A: XGE 3/0/5
	XGE 3/0/5	N/A	Device B: XGE 3/0/5
	XGE 3/0/1	N/A	Device E: XGE 3/0/2
Device E	XGE 3/0/1	N/A	Device C: XGE 3/0/1
Device E	XGE 3/0/2	N/A	Device D: XGE 3/0/1

Applicable product matrix

IMPORTANT:

In addition to running an applicable software version, you must also install the most recent patch, if any.

Device	Software version
S10500, S10500X, S7600, S7600-X, S7600E-X, S7500X, S7500E	R7625 and later
S12500G-AF (type T cards)	R7625 and later
S12500G-AF (type S cards)	R8054P04 and later
S10500X-G, S7500X-G	R7754P04 and later
S5590XP-HI-G, S6520X-EI-G, S6520XP-EI-G	R7754P04 and later
S6550XE-HI, S6525XE-HI	R8106P22 and later
S6520X-EI, S6520X-HI	F6628P11 and later
S5590-HI, S5590-EI, S6805-G, S6850-G, S6530X, S9850-G	R8307P08 and later
S5560X-HI	F6628P11 and later
S5560X-EI	F6628P11 and later

Analysis

· Configure Device A and Device B to form an M-LAG system. Assign the uplink interfaces to an M-LAG group connecting to Device C, and the downlink interfaces to another M-LAG group connecting to Device D.

· Enable loop detection on Device A and Device B.

· Disable the spanning tree feature globally.

Restrictions and guidelines

All the devices were started with the factory default configuration. When you are working on a live network, make sure you understand the potential impact of every command on your network.

Configure the M-LAG devices

Procedure summary

· Configuring M-LAG

· Configuring the interconnect links between the M-LAG system and Device C/Device D

· Configuring loop detection

Configuring M-LAG

Device A	Device B	Description	Remarks
m-lag system-mac 2-2-2	m-lag system-mac 2-2-2	Set the MAC address of the M-LAG system.	You must assign the same M-LAG system MAC address to the member devices in an M-LAG system.
m-lag system-number 1	m-lag system-number 2	Set the M-LAG system number.	You must assign different M-LAG system numbers to the member devices in an M-LAG system.
m-lag system-priority 123	m-lag system-priority 123	Set the M-LAG system priority.	You must set the same M-LAG system priority on the member devices in an M-LAG system.
m-lag standalone enable	m-lag standalone enable	(Optional.) Enable standalone mode for the M-LAG devices.	To avoid that two member devices both act the primary device after the M-LAG system splits, you can enable standalone mode before the M-LAG system splits.
m-lag keepalive ip destination 21.1.1.2 source 21.1.1.1	m-lag keepalive ip destination 21.1.1.1 source 21.1.1.2	Configure the source and destination IPv4 addresses of keepalive packets.	N/A
interface Ten-gigabitethernet3/0/1	interface Ten-gigabitethernet3/0/1	Enter the interface view for the keepalive link.	N/A
port link-mode route	port link-mode route	Configure the interface for keepalive detection to operate in route mode as a Layer 3 interface.	N/A
ip address 21.1.1.1 24	ip address 21.1.1.2 24	Configure the source IPv4 address of keepalive packets.	N/A
quit	quit	Return to system view.	N/A
m-lag mad exclude interface Ten-gigabitethernet3/0/1	m-lag mad exclude interface Ten-gigabitethernet3/0/1	Exclude the keepalive interface from the shutdown action by M-LAG MAD.	N/A
interface bridge-aggregation 1	interface bridge-aggregation 1	Create an Ethernet aggregate interface.	The interface is used as the peer link interface.
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
quit	quit	Return to system view.	N/A
interface range Ten-gigabitethernet 3/0/2 Ten-gigabitethernet 3/0/3	interface range Ten-gigabitethernet 3/0/2 Ten-gigabitethernet 3/0/3	Enter the view of the physical interface for the peer link.	N/A
port link-aggregation group 1	port link-aggregation group 1	Assign the physical interface for the peer link to the peer link aggregation group.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 1	interface bridge-aggregation 1	Enter Ethernet aggregate interface view.	N/A
port m-lag peer-link 1	port m-lag peer-link 1	Specify the aggregate interface (Bridge-Aggregation 1) as the peer link interface.	N/A
undo mac-address static source-check enable	undo mac-address static source-check enable	Disable the static source check feature on the interface to avoid cross peer-link forwarding failure for traffic.	N/A
quit	quit	Return to system view.	N/A

Configuring the interconnect links between the M-LAG system and Device C/Device D

Device A	Device B	Description	Remarks
interface bridge-aggregation 4	interface bridge-aggregation 4	Create the Ethernet aggregate interface connecting to Device C.	N/A
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
port m-lag group 4	port m-lag group 4	Assign the aggregate interface (Bridge-Aggregation 4) to M-LAG group 4.	N/A
quit	quit	Return to system view.	N/A
interface Ten-gigabitethernet 3/0/4	interface Ten-gigabitethernet 3/0/4	Enter the view of the physical interfaces connecting the M-LAG system to Device C.	N/A
port link-aggregation group 4	port link-aggregation group 4	Assign interfaces to an aggregation group.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 5	interface bridge-aggregation 5	Create the Ethernet aggregate interface connecting to Device D.	N/A
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
port m-lag group 5	port m-lag group 5	Assign the aggregate interface (Bridge-Aggregation 5) to M-LAG group 5.	N/A
quit	quit	Return to system view.	N/A
interface Ten-gigabitethernet 3/0/5	interface Ten-gigabitethernet 3/0/5	Enter the view of the physical interfaces connecting the LAG system to Device D.	N/A
port link-aggregation group 5	port link-aggregation group 5	Assign interfaces to an aggregation group.	N/A
quit	quit	Return to system view.	N/A
vlan 100	vlan 100	Create a VLAN.	N/A
quit	quit	Return to system view.	N/A
interface range bridge-aggregation 4 bridge-aggregation 5	interface range bridge-aggregation 4 bridge-aggregation 5	Enter the view of the Ethernet aggregate interface range.	N/A
port link-type trunk	port link-type trunk	Set the link type of the Layer 2 aggregate interface (Bridge-Aggregation 4 and Bridge-Aggregation 5) to trunk.	N/A
port trunk permit vlan 100	port trunk permit vlan 100	Assign the interface to VLAN 100.	N/A
undo port trunk permit vlan 1	undo port trunk permit vlan 1	Remove the interface from VLAN 1.	N/A
port lacp system-priority 100	port lacp system-priority 101	Set the LACP priority.	Configure different LACP priority values for the two devices. This ensures that when a brain split (simultaneous failure of keepalive link and peer link) occurs, only the member port with higher priority (the smaller the value, the higher the priority) is selected.
quit	quit	Return to system view.	N/A

Configuring loop detection

Device A	Device B	Description	Remarks
undo stp global enable	undo stp global enable	Disable the spanning tree feature globally.	N/A
loopback-detection global enable vlan 100	loopback-detection global enable vlan 100	Globally enable loop detection for VLAN 100.	N/A
loopback-detection global action shutdown	loopback-detection global action shutdown	Set the global loop protection action to shutdown.	N/A
loopback-detection interval-time 35	loopback-detection interval-time 35	Set the loop detection interval to 35 seconds.	N/A

Configure Device C/Device D

Procedure summary

· Configuring the interconnect links between Device C/Device D and the LAG devices

· Configuring the interconnect links between Device C/Device D and Device E

· Disabling the spanning tree feature globally on Device C/Device D

Configuring the interconnect links between Device C/Device D and the LAG devices

Device C	Device D	Description	Remarks
vlan 100	vlan 100	Create a VLAN.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 4	interface bridge-aggregation 5	Create the Ethernet aggregate interface connecting to M-LAG devices.	N/A
link-aggregation mode dynamic	link-aggregation mode dynamic	Configure the aggregate interface to operate in dynamic mode.	N/A
quit	quit	Return to system view.	N/A
interface range Ten-gigabitethernet 3/0/4 Ten-gigabitethernet 3/0/5	interface range Ten-gigabitethernet 3/0/4 Ten-gigabitethernet 3/0/5	Enter the view of the physical interfaces connecting the M-LAG system to Device C.	N/A
port link-aggregation group 4	port link-aggregation group 5	Assign interfaces to an aggregation group.	N/A
quit	quit	Return to system view.	N/A
interface bridge-aggregation 4	interface bridge-aggregation 5	Enter Ethernet aggregate interface view.	N/A
port link-type trunk	port link-type trunk	Set the link type of the Layer 2 aggregate interface (Bridge-Aggregation 4) to trunk.	N/A
port trunk permit vlan 100	port trunk permit vlan 100	Assign the interface to VLAN 100.	N/A
undo port trunk permit vlan 1	undo port trunk permit vlan 1	Remove the interface from VLAN 1.	N/A
quit	quit	Return to system view.	N/A

Configuring the interconnect links between Device C/Device D and Device E

Device C	Device D	Description	Remarks
interface Ten-gigabitethernet 3/0/1	interface Ten-gigabitethernet 3/0/1	Enter Ethernet interface view.	N/A
port link-type trunk	port link-type trunk	Set the link type of the interface to trunk.	N/A
port trunk permit vlan 100	port trunk permit vlan 100	Assign Ten-gigabitethernet 3/0/1 (which connects Device C/Device D to Device E) to VLAN 100.	N/A
undo port trunk permit vlan 1	undo port trunk permit vlan 1	Remove the interface from VLAN 1.	N/A
quit	quit	Return to system view.	N/A

Disabling the spanning tree feature globally on Device C/Device D

Device C	Device D	Description	Remarks
undo stp global enable	undo stp global enable	Disable the spanning tree feature globally.	To simulate the loop occurrence.

Configure Device E

Procedure summary

· Configuring the interconnect links between Device E and Device C/Device D

· Disabling the spanning tree feature globally on Device E

Configuring the interconnect links between Device E and Device C/Device D

Device E	Description	Remarks
vlan 100	Create a VLAN.	N/A
quit	Return to system view.	N/A
interface range Ten-gigabitethernet 3/0/1 Ten-gigabitethernet 3/0/2	Enter the view of the Ethernet interface range.	N/A
port link-type trunk	Set the link type of the interface to trunk.	N/A
port trunk permit vlan 100	Assign the interface to VLAN 100.	N/A
undo port trunk permit vlan 1	Remove the interface from VLAN 1.	N/A
quit	Return to system view.	N/A

Disabling the spanning tree feature globally on Device E

Device E	Description	Remarks
undo stp global enable	Disable the spanning tree feature globally.	To simulate the loop occurrence.

Traffic model

This document provides configuration examples of the loop detection feature. The traffic model has no practical significance when a loop exists.

Convergence performance test results

For more information, see "Traffic model."

Verifying the configuration

Commands

Table 1 Verification commands

Device A	Device B	Description
display m-lag summary	display m-lag summary	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display m-lag keepalive	display m-lag keepalive	Displays M-LAG keepalive packet statistics.
display m-lag role	display m-lag role	Displays M-LAG role information.
display loopback-detection	display loopback-detection	Display the loop detection configuration and status.

Procedure

Verifying the M-LAG system status

View the status of the M-LAG system between Device A and Device B to verify that the M-LAG system can be established correctly. Use Device A as an example.

# Display summary information about the peer-link interface and M-LAG interfaces.

[DeviceA]display m-lag summary

Flags: A -- Aggregate interface down, B -- No peer M-LAG interface configured

C -- Configuration consistency check failed

Peer-link interface: BAGG1

Peer-link interface state (cause): UP

Keepalive link state (cause): UP

M-LAG interface information

M-LAG IF M-LAG group Local state (cause) Peer state Remaining down time(s)

BAGG4 4 UP UP -

BAGG5 5 UP UP -

# Display M-LAG keepalive packet statistics and verify that the keepalive packet receive and send status is successful.

[DeviceA]display m-lag keepalive

Neighbor keepalive link status (cause): Up

Neighbor is alive for: 161568 s 338 ms

Keepalive packet transmission status:

Sent: Successful

Received: Successful

Last received keepalive packet information:

Source IP address: 21.1.1.2

Time: 2020/05/11 15:13:37

Action: Accept

M-LAG keepalive parameters

Destination IP address: 21.1.1.2

Source IP address: 21.1.1.1

Keepalive UDP port : 6400

Keepalive VPN name : N/A

Keepalive interval : 1000 ms

Keepalive timeout : 5 sec

Keepalive hold time: 3 sec

# Display M-LAG role information.

[DeviceA]display m-lag role

Effective role information

Factors Local Peer

Effective role Primary Secondary

Initial role None None

MAD DOWN state Yes Yes

Health level 0 0

Role priority 32768 32768

Bridge MAC b0f9-63b6-4c00 b0f9-63b6-4c09

Effective role trigger: peer-link calculation

Effective role reason: Bridge MAC

Configured role information

Factors Local Peer

Configured role Primary Secondary

Role priority 32768 32768

Bridge MAC b0f9-63b6-4c00 b0f9-63b6-4c09

Verifying the loop detection function

After configuration, verify that Device A detects loops on Bridge-Aggregation 4 and Bridge-Aggregation 5 within a loop detection interval and prints the following system logs:

[DeviceA]

%... DeviceA LPDT/4/LPDT_LOOPED: A loop was detected on Bridge-Aggregation4.

%... DeviceA LPDT/4/LPDT_VLAN_LOOPED: A loop was detected on Bridge-Aggregation4 in VLAN 100.

%... DeviceA LPDT/4/LPDT_LOOPED: A loop was detected on Bridge-Aggregation5.

%... DeviceA LPDT/4/LPDT_VLAN_LOOPED: A loop was detected on Bridge-Aggregation5 in VLAN 100.

%...DeviceA LPDT/5/LPDT_VLAN_RECOVERED: A loop was removed on Bridge-Aggregation4 in VLAN 100.

%... DeviceA LPDT/5/LPDT_RECOVERED: All loops were removed on Bridge-Aggregation4.

%... DeviceA LPDT/5/LPDT_VLAN_RECOVERED: A loop was removed on Bridge-Aggregation5 in VLAN 100.

%... DeviceA LPDT/5/LPDT_RECOVERED: All loops were removed on Bridge-Aggregation5.

Use the display loopback-detection command to display the loop detection configuration and status on Device A.

# Display the loop detection configuration and status on Device A.

[DeviceA] display loopback-detection

Loop detection is enabled.

Global loop detection interval is 35 second(s).

Loop is detected on following interfaces:

Interface Action mode VLANs/VSI

Bridge-Aggregation4 Shutdown 100

Bridge-Aggregation5 Shutdown 100

The output shows the following information:

· Device A detected loops on Bridge-Aggregation 4 and Bridge-Aggregation 5 within a loop detection interval.

· Loops on Bridge-Aggregation 4 and Bridge-Aggregation 5 were removed. Use the display interface command to display status of Bridge-Aggregation 4 and Bridge-Aggregation 5.

# Display information about Bridge-Aggregation 4 on Device A.

[DeviceA] display interface Bridge-Aggregation 4

Bridge-Aggregation4

The interface has assigned a M-LAG group.

Current state: DOWN (Loopback detection down)

...

# Display information about Bridge-Aggregation 5 on Device A.

[DeviceA] display interface Bridge-Aggregation 5

Bridge-Aggregation5

The interface has assigned a M-LAG group.

Current state: DOWN (Loopback detection down)

...

The output shows that Bridge-Aggregation 4 and Bridge-Aggregation 5 have been shut down by loop detection.

Verifying the loop detection function upon failures of interfaces on Device A/Device B connecting Device C/Device D

Disconnect the interfaces on Device A connecting Device C/Device D to verify that the loop detection function operates correctly. (Results are the same as those in step 2.)

Upgrade procedure

Pre-upgrade verification commands

Before you perform an upgrade, use the commands in "Verifying the configuration" and the commands in the following table to verify that all requirements are met for an upgrade.

Table 2 Pre-upgrade verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Upgrade procedure

To upgrade software:

1. Execute the display version command to verify the current BootWare image version and startup software version.

2. Use the release notes for the upgrade software version to evaluate the upgrade impact on your network and verify the following items:

¡ Software and hardware compatibility.

¡ Version and size of the upgrade software.

¡ Compatibility of the upgrade software with the current BootWare image and startup software image.

3. Use the release notes to verify whether the upgrade software images require a license. If licenses are required, check the system for availability of valid licenses. If no license exists on the device, first install a license. If you do not install a license, the software package will fail to be installed.

4. Use the dir command to verify that the device has sufficient storage space for the upgrade images. If the storage space is not sufficient, delete unused files by using the delete command. Make sure that all MPUs in the system have sufficient storage space.

5. After Device A and Device B form an M-LAG system, perform the following tasks:

a. Check the LLDP neighbors of Device A to obtain the LLDP state information of all interfaces on Device A.

b. Manually shut down all interfaces connecting to the other devices (except the peer-link and keepalive interfaces) on Device A.

c. Switch all incoming and outgoing traffic of Device A to Device B.

6. Save the configuration on Device A, and use FTP or TFTP to transfer the upgrade image file to the root directory of a file system. Upgrade Device A and reboot it.

7. When Device A is being rebooted, manually shut down the interconnect interfaces connecting Device B to Device A, typically the peer-link and keepalive interfaces.

8. After Device A is rebooted, bring up the interfaces that have been shut down on Device B. Wait for M-LAG to restore between Device A and Device B.

9. After Device A and Device B form a new M-LAG system again, bring up the interfaces connecting to the other devices. Wait for the traffic to restore.

For more information about upgrading software on an M-LAG system, see H3C Switches M-LAG System Upgrade Guide.

For more information about the software upgrade procedure, see the fundamentals configuration guide for the device.

Estimated upgrade downtime

N/A, as described in “Traffic model.”

Post-upgrade verification commands

After the upgrade finishes, use the commands in "Verifying the configuration" and the commands in the following table to verify that the upgrade has been done correctly.

Table 3 Post-upgrade verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Node expansion

Pre-expansion verification commands

Before you perform a node expansion, use the commands in "Verifying the configuration" and the commands in the following table to verify that all requirements are met for an expansion.

Table 4 Pre-expansion verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Node expansion

1. Make sure the expansion device is not connected to the management network.

2. Upgrade the device to the target software version.

3. Preconfigure the device.

4. Connect the device to the management network.

Estimated expansion downtime

For more information, see "Traffic model."

Post-expansion verification commands

After the expansion finishes, use the commands in the following table to verify that the expansion has been done correctly.

Table 5 Post-expansion verification commands

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacement procedure

Service module replacement

Checking the environment

Execute the commands in "Verifying the configuration" and the following commands to verify that all requirements are met for a replacement.

Table 6 Pre-replacement verification commands

Device A	Device B	Description
display device	display device	Displays device information.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacement procedure

Before you replace an interface module, make sure the service and management traffic has switched over to other interface modules that are operating correctly.

Replace the interface modules online while the system is operating or power off the system before you do the replacement, depending on the evaluation of the conditions.

Estimated replacement downtime

For more information, see "Traffic model."

Post-replacement verification commands

Use the same commands for pre-replacement verification to verify that the system can operate correctly after the hardware replacement.

Switching fabric module replacement

Pre-replacement verification commands

Execute the commands in "Verifying the configuration" and the following commands to verify that all requirements are met for a replacement.

Table 7 Command check summary before replacement

Device A	Device B	Description
display device	display device	Displays summary information about the peer link interfaces and M-LAG interfaces in the M-LAG system.
display boot-loader	display boot-loader	Displays the current software images and startup software images.
display version	display version	Displays system version information.

Replacement procedure

Replace the switching fabric module online while the system is operating or power off the system before you do the replacement, depending on the evaluation of the conditions.

Verifying the traffic interruption time

For more information, see "Traffic model."

Post-replacement verification commands

Use the same commands for pre-replacement verification to verify that the system can operate correctly after the hardware replacement.

H3C Campus Switches M-LAG Configuration Guide-6W101

Analysis

Configuring M-LAG

Configuring the interconnect links between Device C/Device D and the LAG devices

Configuring the interconnect links between Device E and Device C/Device D

Traffic model

Verifying the M-LAG system status

Verifying the loop detection function

Verifying the loop detection function upon failures of interfaces on Device A/Device B connecting Device C/Device D

Checking the environment

Replacement procedure

Estimated replacement downtime

Post-replacement verification commands

Pre-replacement verification commands

Replacement procedure

Verifying the traffic interruption time

Post-replacement verification commands

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