Indicates the number of downstream packets in the
ACL-based VLAN traffic statistics collection.
After the first query, 0 is fixedly returned. After the second query,
traffic statistics of the VLAN between the two queries are returned.
If the query or delete operation is not performed on the traffic statistics
of this VLAN within 10 minutes, the traffic statistics collection of the VLAN is invalid.
If a new index is specified in the second query, the traffic statistics of
the new VLAN are collected. The system can collect the traffic
statistics of a maximum of 64 VLANs concurrently.