Flexible Interface Encapsulation (FlexEncap)

References

https://www.arista.com/en/support/toi/eos-4-24-2f/14551-flexible-interface-encapsulation-flexencap

 

FlexEncap is symmetric meaning that in the following examples, the router pops the matching VLAN off as traffic comes into the router, and pushes it back on when traffic leaves the router. If the traffic is double tagged and a sub-interface is configured to match only the outer most tag, only the outer tag is popped/pushed on ingress/egress.

 

Match single VLAN ID 10 and terminate at L3:

interface Ethernet20/1.10
   encapsulation vlan
      client dot1q 10
   ip address 10.0.10.0/31

 

Match outer VLAN ID 20 (may or may not have an inner VLAN ID) and terminate at L2 (bridge into VLAN 2):

interface Ethernet20/1.20
   vlan id 2
   encapsulation vlan
      client dot1q 20

 

Match VLAN untagged traffic and terminate at L3:

interface Ethernet20/1.30
   encapsulation vlan
      client untagged network untagged
   ip address 192.168.0.0/31

 

Match all traffic (tagged or untagged) which doesn't match any other sub-interface encapsulation and terminate ate L2 (bridge into VLAN 3):

interface Ethernet20/1.4096
   vlan id 3
   encapsulation vlan
      client unmatched

 

Show configured encapsulations:

#show interface encapsulation vlan
Interface                Status         ID       Client Encapsulation       Network Encapsulation
------------------------ -------------- -------- -------------------------- ---------------------
Ethernet20/1.10          inactive                dot1q outer 10
Ethernet20/1.20          inactive                dot1q outer 20
Ethernet20/1.30          inactive                untagged                   untagged
Ethernet20/1.4096        inactive                unmatched

 

---