This read-only object indicates the traffic direction - other(1), ingress(2), or egress(3) - for the subscriber accounting row it belongs to, and together with oaSubscrName forms the table index. Admins use it to distinguish a subscriber's inbound traffic accounting from their outbound accounting, since each direction gets its own row of counters. For example, two rows for the same subscriber name might exist, one with oaSubscrDirection egress(3) tracking upload traffic and one with ingress(2) tracking downloads.