Description

On Q-in-Q enabled interface, IFL counters are not incremented though there is a traffic.
This is a product limitation which cannot be fixed. This KB describes this behavior.

Symptoms

For example, when Q-in-Q is enabling on ge-0/0/1.2000, there is no IFL counters are incremented. 
root@EX4400# run show interfaces ge-0/0/1.2000 extensive
  Logical interface ge-0/0/1.2000 (Index 559) (SNMP ifIndex 549) (Generation 144)
    Flags: Up SNMP-Traps Redundancy-Device 0x20004000 VLAN-Tag [  10-100 ] In(push .2000) Out(pop)  Encapsulation: Extended-VLAN-Bridge
    Traffic statistics:
     Input  bytes  :                    0
     Output bytes  :                    0
     Input  packets:                    0
     Output packets:                    0
    Local statistics:
     Input  bytes  :                    0
     Output bytes  :                    0
     Input  packets:                    0
     Output packets:                    0
    Transit statistics:
     Input  bytes  :                    0                    0 bps   <<<======== Here
     Output bytes  :                    0                    0 bps   <<<======== Here
     Input  packets:                    0                    0 pps   <<<======== Here
     Output packets:                    0                    0 pps   <<<======== Here
    Protocol eth-switch, MTU: 1522, Generation: 161, Route table: 8, Mesh Group: __all_ces__, Next-hop: 1728, vpls-status: up
      Flags: 0x4000000
There is no problem on IFD counters. 
root@EX4400# run show interfaces ge-0/0/1 extensive
Physical interface: ge-0/0/1, Enabled, Physical link is Up
  Interface index: 652, SNMP ifIndex: 517, Generation: 143
  Link-level type: Extended-VLAN-Bridge, MTU: 1522, LAN-PHY mode, Link-mode: Full-duplex, Speed: 1000mbps, BPDU Error: None, Loop Detect PDU Error: None, Ethernet-Switching Error: None, MAC-REWRITE Error: None, Loopback: Disabled,
  Source filtering: Disabled, Flow control: Enabled, Auto-negotiation: Enabled, Remote fault: Online, Media type: Copper, IEEE 802.3az Energy Efficient Ethernet: Disabled, Auto-MDIX: Enabled
  Device flags   : Present Running
  Interface Specific flags: Internal: 0x100000
  Interface flags: SNMP-Traps Internal: 0x20004000
  Link flags     : 0x800
  CoS queues     : 12 supported, 12 maximum usable queues
  Hold-times     : Up 0 ms, Down 0 ms
  Current address: 88:88:88:88:88:88, Hardware address: 88:88:88:88:88:88
  Last flapped   : 2023-04-25 00:06:05 PDT (01:00:45 ago)
  Statistics last cleared: Never
  Traffic statistics:
   Input  bytes  :                80713                 9688 bps   <<<======== Here
   Output bytes  :                33654                 9424 bps   <<<======== Here
   Input  packets:                  451                   11 pps   <<<======== Here
   Output packets:                  320                   11 pps   <<<======== Here

Solution

This is a product limitation due to below:
-Interface statistics are obtained by attaching counters to VLAN table in hardware.
-Since multiple interfaces can be a part of the same VLAN,  and as counters are provided at VLAN level, interface stats is not possible on IFL basis.
-There is no hardware supportability to cover this.

Modification History

2023-08-23 : Created a KB.