Networking Requirements

In Figure 1, the SwitchB has dual-access to the network through SwitchA1 and SwitchA2 using LACP LAGs.

At first, the SwitchB accesses the network through SwitchA1. If SwitchA1 or the link between SwitchB and SwitchA1 fails, SwitchB cannot communicate with the network. To avoid service interruptions, we can configure MLAG on SwitchA1 and SwitchA2. When communication between the SwitchB and SwitchA1 fails, traffics from the SwitchB will be switched to SwitchA2 keeping communication with the network. When SwitchA1 or the link between SwitchB and SwitchA1 recovers, traffic from the SwitchB will be switched back to SwitchA1.

MLAG implements a backup link aggregation group between SwitchA1 and SwitchA2 to improve network reliability.

Figure 1 MLAG Topology

Procedure

SwitchA1

Step1 Configure an aggregation interface with LACP mode.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options lacp enable true

admin@SwitchA1# set interface aggregate-ethernet ae2 aggregated-ether-options lacp enable true

Step2 Enable MLAG on a LAG.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag disable false

By default, MLAG function is enabled.

Step3 Configure MLAG domain ID.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag domain-id 1

Step4 Add member interfaces to a LAG.

admin@SwitchA1# set interface gigabit-ethernet ge-1/1/1 ether-options 802.3ad ae1

admin@SwitchA1# set interface gigabit-ethernet te-1/1/49 ether-options 802.3ad ae2

admin@SwitchA1# set interface gigabit-ethernet te-1/1/50 ether-options 802.3ad ae2

Step5 Configure VLAN.

admin@SwitchA1# set vlans vlan-id 15

admin@SwitchA1# set vlans vlan-id 16

admin@SwitchA1# set vlans vlan-id 4094 l3-interface vlan4094

admin@SwitchA1# set interface aggregate-ethernet ae1 family ethernet-switching port-mode trunk

admin@SwitchA1# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 15

admin@SwitchA1# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 16

admin@SwitchA1# set interface aggregate-ethernet ae2 family ethernet-switching native-vlan-id 4094

admin@SwitchA1# set interface aggregate-ethernet ae2 family ethernet-switching port-mode trunk

admin@SwitchA1# set interface aggregate-ethernet ae2 family ethernet-switching vlan members 15

admin@SwitchA1# set interface aggregate-ethernet ae2 family ethernet-switching vlan members 16

Step6 Configure the L3 interface IP address.

admin@SwitchA1# set vlan-interface interface vlan4094 vif 4094 address 10.10.0.1 prefix-length 24

Step7 Configure the peer IP address and the peer-link for the MLAG peer.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag peer 10.10.0.2 peer-link ae2

Step8 Configure a static ARP entry for peer-link interface.

admin@SwitchA1# set interface gigabit-ethernet ae2 static-ethernet-switching mac-address CC:37:AB:B6:9C:33 vlan 4094

admin@SwitchA1# set protocols arp interface vlan4094 address 10.10.0.2 mac-address CC:37:AB:B6:9C:33

NOTE:

PICA8 recommends configuring a static ARP for peer-link interface to prevent ARP entry of the peer-link interface from being modified by ARP attack packets.

Step9 (Optional) Configure MLAG system priority.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag priority 2

Step10 (Optional) Configure hello interval timer.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag hello-interval 2

Step11 (Optional) Configure reload delay timer.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag reload-delay 300

Step12 Configure system ID for LACP negotiation.

admin@SwitchA1# set interface aggregate-ethernet ae1 aggregated-ether-options mlag system id 00:B0:BC:00:00:00

System ID configured on the MLAG peer devices should be consistent.

SwitchA2

The configuration on SwitchA2 is the same as SwitchA1.

Step1 Configure an aggregation interface with LACP mode.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options lacp enable true

admin@SwitchA2# set interface aggregate-ethernet ae2 aggregated-ether-options lacp enable true

Step2 Enable MLAG on a LAG.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag disable false

By default, MLAG funtion is enabled.

Step3 Configure MLAG domain ID.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag domain-id 1

Step4 Add member interfaces to a LAG.

admin@SwitchA2# set interface gigabit-ethernet ge-1/1/2 ether-options 802.3ad ae1

admin@SwitchA2# set interface gigabit-ethernet te-1/1/49 ether-options 802.3ad ae2

admin@SwitchA2# set interface gigabit-ethernet te-1/1/50 ether-options 802.3ad ae2

Step5 Configure VLAN.

admin@SwitchA2# set vlans vlan-id 15

admin@SwitchA2# set vlans vlan-id 16

admin@SwitchA2# set vlans vlan-id 4094 l3-interface vlan4094

admin@SwitchA2# set interface aggregate-ethernet ae1 family ethernet-switching port-mode trunk

admin@SwitchA2# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 15

admin@SwitchA2# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 16

admin@SwitchA2# set interface aggregate-ethernet ae2 family ethernet-switching native-vlan-id 4094

admin@SwitchA2# set interface aggregate-ethernet ae2 family ethernet-switching port-mode trunk

admin@SwitchA2# set interface aggregate-ethernet ae2 family ethernet-switching vlan members 15

admin@SwitchA2# set interface aggregate-ethernet ae2 family ethernet-switching vlan members 16

Step6 Configure the L3 interface IP address.

admin@SwitchA2# set vlan-interface interface vlan4094 vif 4094 address 10.10.0.2 prefix-length 24

Step7 Configure the peer IP address and the peer-link for the MLAG peer.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag peer 10.10.0.1 peer-link ae2

Step8 Configure a static ARP entry for peer-link interface.

admin@SwitchA2# set interface gigabit-ethernet ae2 static-ethernet-switching mac-address 00:18:23:30:E7:90 vlan 4094

admin@SwitchA2# set protocols arp interface vlan4094 address 10.10.0.1 mac-address 00:18:23:30:E7:90

NOTE:

PICA8 recommends configuring a static ARP for peer-link interface to prevent ARP entry of the peer-link interface from being modified by ARP attack packets.

Step9 (Optional) Configure MLAG system priority.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag priority 3

Step10 (Optional) Configure hello interval timer.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag hello-interval 2

Step11 (Optional) Configure reload delay timer.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag reload-delay 300

Step12 Configure system ID for LACP negotiation.

admin@SwitchA2# set interface aggregate-ethernet ae1 aggregated-ether-options mlag system id 00:B0:BC:00:00:00

System ID configured on the MLAG peer device should be consistent.

SwitchB

Step1 Enable aggregation interface with LACP mode

admin@SwitchB# set interface aggregate-ethernet ae1 aggregated-ether-options lacp enable true

Step2 Add member interfaces to a LAG.

admin@SwitchB# set interface gigabit-ethernet ge-1/1/1 ether-options 802.3ad ae1

admin@SwitchB# set interface gigabit-ethernet ge-1/1/2 ether-options 802.3ad ae1

Step3 Configure VLAN.

admin@SwitchB# set vlans vlan-id 15

admin@SwitchB# set vlans vlan-id 16

admin@SwitchB# set interface aggregate-ethernet ae1 family ethernet-switching port-mode trunk

admin@SwitchB# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 15

admin@SwitchB# set interface aggregate-ethernet ae1 family ethernet-switching vlan members 16

Verify the Configuration

• You can use the run show mlag configuration command on Switch A1 or SwitchA2 to view the information of an MLAG domain.

admin@SwitchA1# run show mlag configuration

Domain-id Local-LAG System-id Priority Peer Peer-link Hello-interval

----------------------------------------------------------------------------------------------------------------------

1 ae1 60:eb:69:d2:9c:d7 3 10.10.0.1 ae2 4

• You can use the run show mlag peer domain-id command to view the status of MLAG peerdevice of an MLAG domain.

admin@SwitchA1# run show mlag peer 1

Peer System-id State Link-status

--------------------------------------------------------------------------------------------

10.10.0.1 48:0f:cf:af:50:7f FULL UP

• You can use the run show mlag internal command to view the status of MLAG interface state, and view the results of the consistency check.

admin@SwitchA1# run show mlag internal

Domain-id Local-LAG Flood MAC-sync State Config-Match Role

-----------------------------------------------------------------------------------------------------------------

1 ae1 false true FULL CONFIG_MATCH MASTER

admin@SwitchA2# run show mlag internal

Domain-id Local-LAG Flood MAC-sync State Config-Match Role

-----------------------------------------------------------------------------------------------------------------

1 ae1 false true FULL CONFIG_MATCH SLAVE

• You can run the run show mlag internal domain-id detail command on each peer-link device to view the details of the configuration items.

admin@SwitchA1# run show mlag internal 1 detail

Local-LAG: ae1

Native VlanID: 1

Mac Learning: true

Untagged VlanID:

Tagged VlanID: 15

• You can use the run show lacp internal command to view the config information of local LACP.

admin@SwitchA1# run show lacp internal

LACP System ID: 32768,48:0F:CF:AF:50:7F

Aggregated interface: ae1

Port Number Priority Admin Key Oper Key State Receive State Transmit State Mux State

-------------- -------- --------- -------- ----- ------------- -------------- ------------------

ge-1/1/1 32768 0x202 0x202 0x3D Current Slow Periodic Collecting Distributing

Aggregated interface: ae2

Port Number Priority Admin Key Oper Key State Receive State Transmit State Mux State

-------------- -------- --------- -------- ----- ------------- -------------- -----------------

te-1/1/49 32768 0x50 0x50 0x3D Current Slow Periodic Collecting Distributing

te-1/1/50 32768 0x50 0x50 0x3D Current Slow Periodic Collecting Distributing

• You can use the run show lacp neighbor command to view the config information of LACP neighbor.

admin@SwitchA1# run show lacp neighbor

Aggregated interface: ae1

Port Number Partner System ID Partner Port Num Port Priority Admin Key Oper Key State

----------- ----------------------- ---------------- ------------- --------- -------- -----

ge-1/1/1 32768,08:9E:01:61:64:13 1 32768 0x00 0x35 0x3D

Aggregated interface: ae2

Port Number Partner System ID Partner Port Num Port Priority Admin Key Oper Key State

--------------------------------------------------------------------------------------------------------------------------------------------------

te-1/1/49 32768,70:72:CF:B7:60:A5 73 73 32768 0x00 0x50 0x3D

te-1/1/50 32768,70:72:CF:B7:60:A5 73 74 32768 0x00 0x50 0x3D

• You can use the following commands on SwitchB to verify configuration:

- run show lacp neighbor command to view the config information of LACP neighbor.
  Aggregated interface: ae1
  Port Number Partner System ID Partner Port Num Port Priority Admin Key Oper Key State
  --------------------------------------------------------------------------------------------------------------------------------------------------
  ge-1/1/1 32768,48:0F:CF:AF:50:7F 1 32768 0x00 0x202 0x3D
  ge-1/1/2 32768,48:0F:CF:AF:50:7F 513 32768 0x00 0x202 0x3D
- run show lacp internal command to view the config information of local LACP.
  LACP System ID: 32768,08:9E:01:61:64:13
  Aggregated interface: ae1
  Port Number   Priority   Admin Key   Oper Key   State   Receive State   Transmit State   Mux State
  -------------- -------- --------- -------- -----   ------------- -------------- ------------------
  ge-1/1/1 32768      0x35 0x35 0x3D Current Slow Periodic    Collecting Distributing
  ge-1/1/2 32768      0x35 0x35 0x3D Current Slow Periodic    Collecting Distributing