Regardless of its association, the extended VLAN tagging operation configuration data ME pertains to upstream traffic. This attribute specifies the mode for downstream mapping. 1 The operation performed in the downstream direction is the inverse of that performed in the upstream direction. For one-to-one VLAN mappings, the inverse is trivially defined. Many-to-one mappings are possible, however, and these are treated as follows. If the many-to-one mapping results from multiple operation rules producing the same ANI-side tag configuration, then the first rule in the list defines the inverse operation. If the many-to-one mapping results from don't care fields in the filter being replaced with provisioned fields in the ANI-side tags, then the inverse is defined to set the corresponding fields on the ANI side with their lowest value. 2 No operation is performed in the downstream direction. 3 Filter on VID and p-bit value. On a match, perform the inverse operation on both the VID and p-bit value. If no match is found, forward the frame unmodified. 4 Filter on VID only. On a match, perform the inverse VID operation only; pass the p bits through. If no match is found, forward the frame unmodified. 5 Filter on p-bit only. On a match, perform the inverse p-bit operation only; pass the VID through. If no match is found, forward the frame unmodified. 6 Filter on VID and p-bit value. On a match, perform the inverse operation on both the VID and p-bit value. If no match is found, discard the frame. 7 Filter on VID. On a match, perform the inverse operation on the VID only; pass the p bits through. If no match is found, discard the frame. 8 Filter on p-bit only. On a match, perform the inverse p-bit operation only; pass the VID through. If no match is found, discard the frame. 9 Regardless of the filter rules, discard all downstream traffic.