A bridged ethernet network sometimes requires that a physical port be subdivided into virtual ports to allow peering with more bridging elements than the number of physical ports allows.  Currently, ATM VPs/VCs and Frame Relay paths are used in the communications industry to establish such virtual ports.  However, for very high bandwidths these technologies are not suitable due to both technical reasons and their high cost.  On the other hand SONET/SDH devices can easily scale to very high bandwidths and are widespread in metropolitan and wide area networks (MAN/WAN). 
There is a need, therefore, for means to economically and effectively bridge network access devices transporting optical line data, such as from a fiber channel (FC) or Gigabit Ethernet (GbE) interface, to a SONET metropolitan area network (MAN)/wide area network (WAN).