show interfaces irb.xxx

Hi all,

Which statistics does interface irb show in "show interfaces irb.xxx extensive" ? What kind of packets does switch count?

I don't use irb interface in my ex4600 for transit traffic, but traffic statistics counters are growing up.

show interfaces irb.100 extensive
  Logical interface irb.100 (Index 679) (SNMP ifIndex 918) (HW Token 65535) (Generation 587)
    Flags: Up SNMP-Traps 0x4000 Encapsulation: ENET2
    Bandwidth: 1000mbps
    Routing Instance: default-switch Bridging Domain: OpStack_CEPH_cluster-100
    Traffic statistics:
     Input  bytes  :         331478979943
     Output bytes  :                    0
     Input  packets:             74242953
     Output packets:                    0
    Local statistics:
     Input  bytes  :                    0
     Output bytes  :                    0
     Input  packets:                    0
     Output packets:                    0
    Transit statistics:
     Input  bytes  :         331478979943                    0 bps
     Output bytes  :                    0                    0 bps
     Input  packets:             74242953                    0 pps
     Output packets:                    0                    0 pps
    Protocol inet, MTU: 9186, Generation: 512, Route table: 0
      Flags: Sendbcast-pkt-to-re
      Addresses, Flags: Is-Preferred Is-Primary
        Destination: 172.31.100/24, Local: 172.31.100.254, Broadcast: 172.31.100.255, Generation: 164