A SUB-RATE TRANSMISSION METHOD FOR USER DATA SERVICES IN TRANSMISSION DEVICES OF A METROPOLITAN AREA NETWORK

摘要

The present invention discloses a sub-rate transmission method for user dataservicesin transmission devices of a Metropolitan Area Network (MAN). The methodcomprisesthe steps of: pre-configuring each transmission device to form forwardingtable itemsrepresenting corresponding relationship between self-defined tags andtransmission lines;after receiving a user data frame, an original transmission device nesting aself-definedtag into the user data frame according to said forwarding table items to formaself-defined data frame, then transmitting the self-defined data frame; andafter receivingthe self-defined data frame, a terminal transmission device determining anoutput port fortransferring the data frame by searching the forwarding table items with thenestedself-defined tag, then deleting the nested self-defined tag and sending theoriginal userdata frame to the said output port. The present invention, by nesting a self-defined tag,can greatly increase the number of Virtual Local Area Networks (VLANs)accommodatedby a MAN as well as simplify the configuration of tags for user data to bringmoreconvenience to users.