ENCAPSULATION OF AN ADDRESS WITHIN A FORWARDED FRAME IN A COMPUTER COMMUNICATIONS SYSTEM

摘要

There is provided means to preserve the multicast address of a frame on a first communications system having a large multicast address space when the frame is forwarded onto a second communications system having a small multicast address space. A connection apparatus is provided for connecting a first communications system with a second communications system. There is a means for receiving at least one first frame from said first communications system, said at least one first frame having a destination address field, said destination address field containing a desired destination address, and there is a means for forwarding said at least one first frame onto said second communications system as a second frame, and for writing a second destination address into a destination address field of said second frame. Also there is a means for writing said desired destination address into a predetermined field of said second frame, and a means for writing an indicator into said second frame, said indicator capable of being interpreted by a receiving station to mean that said desired destination address is written into said predetermined field of said second frame. The frame may be forwarded onto a third communications system supporting the multicast address structure of the first communications system, and the multicast address is recovered from the representation of the multicast address written into the second frame and the multicast address is written into the address field of a third frame transmitted onto the third communications system.