This article showcases how ESI LAG is configured in an EVPN-VXLAN topology.

LAB Topology:

• 2x QFX5120 switches are used as EVPN/VXLAN leaf devices
• 1x EX4400 switch is used as access/client device
• an ESI LAG will be configured between the leaf switches and the access device

   +--------------------+                      +---------------------+ 
   |                    |                      |                     |
   |                    |                      |                     |
   |  QFX5120-48Y-8C-1  |                      |  QFX5120-48Y-8C-2   |
   |  21.4R3-S5         |                      |   21.4R3-S5         |
   |                    |                      |                     |
   |                    |                      |                     |
   +--------------+-----+                      +-----+---------------+
         et-x/x/x \            ESI                 / et-x/x/x            
                    \x:x:x:x:x:x:x:x:x:x.          /
                     \============ aexx ==========/ (ae9)
                      \                          / 
                       \                        /
                        \                      /
                         \                    /
                          \                  /              
                 et-x/x/x  \ ======aex======/et-x/x/x (ae1)
                        +---\--------------/---+          
                        |                      |          
                        |       EX4400-48P     |          
                        |        22.3R2.10     |                 
                        |                      |         
                        +----------------------+          

Configuration needed on the EVXPN/VXLAN switches:

set chassis aggregated-devices ethernet device-count 100

// binding physical interfaces to the LAG (AE9 in this example)

set interfaces et-0/0/48 ether-options 802.3ad ae9

set interfaces et-0/0/49 ether-options 802.3ad ae9

// configuring ESI and Link Aggregation Control Protocol (LACP)

// LACP on the LAG to provide a standardized means for exchanging information between partner systems on a link

// LACP system ID needs to be configured with identical value on both leaf switches in order to appear as an sigle device to the access switch.

// ESI needs to be configured with an identical value on both leaf switches as part of the EVPN multihoming setup

// LAG ID (AE9 in this example) needs to be configured with identical values on both leaf switches in order for the links to be considered part of the same LAG and be bundled into it

set interfaces ae9 description to-access-switch

set interfaces ae9 esi 00:02:00:00:00:00:21:00:00:21 // manually configuring an Ethernet Segment Identifier (ESI)

set interfaces ae9 esi all-active

set interfaces ae9 aggregated-ether-options lacp active

set interfaces ae9 aggregated-ether-options lacp system-id 02:00:00:00:00:21. // manually configuring the LACP system ID

set interfaces ae9 unit 0 family ethernet-switching interface-mode trunk // configuring the LAG as an L2 trunk

set interfaces ae9 unit 0 family ethernet-switching vlan members all // permitting all VLAN IDs on the link

Configuration needed on the access switch:

set chassis aggregated-devices ethernet device-count 100

// binding physical interfaces to the LAG (AE1 in this example)

set interfaces et-0/0/48 ether-options 802.3ad ae1

set interfaces et-0/0/49 ether-options 802.3ad ae1

// configuring Link Aggregation Control Protocol (LACP) that provides a standardized means for exchanging information between partner systems on a link

set interfaces ae1 aggregated-ether-options lacp active

set interfaces ae1 aggregated-ether-options lacp periodic fast

set interfaces ae1 description to-evpn-vxlan-leaf-switches

set interfaces ae1 unit 0 family ethernet-switching interface-mode trunk // configuring the LAG as an L2 trunk

set interfaces ae1 unit 0 family ethernet-switching vlan members all // permitting all VLAN IDs on the link

More information on this topic: EVPN Multihoming Overview