VLAN frame format

摘要

In a network device such as a network switch having a port coupled to a communications medium dedicated to a single virtual local area network and another port coupled to a communications medium shared among multiple virtual local area networks for transmitting data frames between the dedicated communications medium and the shared communications medium, a method of identifying the virtual network associated with each data frame received by the network switch when transmitting the data frames over the shared communications medium. The method comprises receiving data frames from the dedicated communications medium coupled to one port, and, with respect to each data frame so received, inserting a new type field and a virtual network identifier field. The contents of the new type field indicate the data frame comprises a virtual network identifier field. The method further includes placing a value in the virtual network identifier field identifying the virtual network associated with the data frame and transmitting the data frame over the shared communications medium. Upon receipt of the data frames from over the shared communications medium, another network device can discern from the virtual network identifier field in each data frame the virtual network from which the data frames were received and determine whether to forward the data frames accordingly.

主权项

id="REI-00003" date="20150519" 1. A method of identifying a virtual network associated with a data frame when transmitting said data frame between a communications medium and a shared communications medium, comprising the steps of:
a) receiving said data frame from said communications medium, said data frame comprising a first type field and a data field; b) inserting a second type field at a location within said data frame preceding said first type field, said second type field indicating said data frame comprises a virtual network identifier field; c) inserting said virtual network identifier field at a location between said second typo field and said first type field; d) assigning a first value to said virtual network identifier field, said first value corresponding to said virtual network; and e) transmitting said data frame over said shared communications medium.