| 摘要 |
Modification of an Ethernet data packet for transmission within a system or over a link wherein a VLAN header is unnecessary comprises (i) determining whether the packet includes a VLAN tag header 41 and a VLAN identification field; (ii) inserting, when the packet does not include a VLAN tag header and a VLAN identification field, a first field, including a first indication of the absence of the said VLAN tag header and said VLAN identification field, and a second field constituting a dummy field; and (iii) inserting, in place of the VLAN tag header if said header and said VLAN identification field are present, a field including a second indication 42, denoting the presence of said VLAN identification field, and selected information 43. The first and second indications are preferably different values of a one-bit field and the selected information may be proprietary information.
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