Many to few group address translation through a network bridge

• US 5,428,615 A
• Filed: 07/21/1994
• Issued: 06/27/1995
• Est. Priority Date: 01/25/1991
• Status: Expired due to Term

• Current Assignee: Enterasys Networks Incorporated (Extreme Networks, Inc.)
• Original Assignee: Digital Equipment Corporation (HP Inc.)
• Inventors: Backes, Floyd J., Hawe, William R., Koning, G. Paul, Mitton, David J., Perlman, Radia J.
• Primary Examiner(s): Olms, Douglas W.
• Assistant Examiner(s): Jung, Min
• Application Number:
  US08/278,686
• Time in Patent Office: 341 Days
• Field of Search: 370/85.13, 370/85.14, 370/85.9, 370/79, 370/94.1, 370/85.1
• US Class Current: 370/392
• CPC Class Codes: H04L 12/1836 with heterogeneous network architecture
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 2212/00 Encapsulation of packets
• CPC Class Codes: H04L 45/742 Route cache; Operation thereof

Abstract

A connection apparatus for connecting a first communication system with a second communication system and a third communication system. A first frame is received from the first communication system, where the first frame has a multicast address as a destination address, and where the destination address requires the first frame to be transmitted onto the second communication system. The multicast address is translated into a functional address, and the functional address is written into a second frame transmitted onto the second communication system. The second frame is received and is transmitted onto a third communication system, and the functional address is translated into a multicast address for the third communication system, and the multicast address is written into a destination field of the frame as it is transmitted onto the third communication system. The second communication system may be a token ring system based upon an IEEE 802.5 standard, and the functional address may be written into a DSAP field and into a PROTOCOL TYPE field of an 802.5 Standard frame.

Claims

1. A connection apparatus for connecting a first communications system with a second communications system and a third communications system, comprising:

means for receiving at least one first frame from said first communications system, said at least one first frame having a multicast address as a destination address, said multicast address requiring said at least one first frame to be transmitted onto said second communications system;

means for translating said multicast address to a functional address, said functional address capable of translation by a station receiving a frame containing said functional address into said multicast address; and

,

means for writing said functional address into a second frame and for transmitting said second frame onto said second communications system, a station receiving said second frame to write said multicast address translated from said functional address into a destination address field of a third frame before transmitting said third frame onto said third communications system.

2. A connection apparatus as in claim 1 further comprising:

means for receiving at least one second frame from said second communications system, said at least one second frame having a functional address contained therein;

means, responsive to said functional address for recovering said multicast address from said functional address and for placing said multicast address into a destination address field of a third frame transmitted onto said third communications system.

3. The apparatus as in claim 1 wherein said functional address is

placed in at least one designated field of said second frame.

4. The apparatus as in claim 1 wherein said first communications system is an ethernet industry standard communications system.

5. The apparatus as in claim 1 wherein said first communications is an ethernet system based upon an IEEE 802.3 standard.

6. The apparatus as in claim 1 wherein said first communications system is a token ring based upon a Fiber Distributed Data Interface ANSI/IEEE FDDI (ISO 9314) standard.

7. The apparatus as in claim 1 wherein said second communications system is a token ring system based upon an IEEE 802.5 standard.

8. The apparatus as in claim 1 wherein said means for translating said multicast address to a functional address further comprises:

a table containing at least one multicast address and a corresponding functional address;

means, responsive to said multicast address, for retrieving from said table said corresponding functional address.

9. The apparatus as in claim 8 wherein:

said at least one multicast address is a plurality of multicast addresses and each multicast address of said plurality of said multicast addresses has a corresponding unique functional address; and

said means for retrieving from said table retrieves the corresponding unique functional address for each of said multicast address of said plurality of said multicast addresses.

10. The apparatus as in claim 1 wherein:

said functional address is divided into two values, and the first value is written into a DSAP field of said second frame and the second value is written into a PROTOCOL TYPE field of said second frame.

11. The apparatus as in claim 10 further comprising:

means for receiving an incoming frame from said second communications system;

means, responsive to said first value in said DSAP field of said incoming frame and said second value in said PROTOCOL TYPE field of said incoming frame, for retrieving from said table a corresponding multicast address;

means for writing said corresponding multicast address into a DESTINATION ADDRESS field of an outgoing frame; and

means for transmitting said outgoing frame onto said third communications system.

12. The apparatus as in claim 1 wherein:

said functional address is written into a standard header field of said second frame.

13. The apparatus as in claim 1 wherein:

said multicast address is written into a standard destination address field of said third frame.

14. A connection apparatus for connecting a first communications system with a second communications system, comprising:

means for receiving at least one first frame from said first communications system, said at least one first frame having a multicast destination address, said multicast destination address requiring said at least one first frame to be transmitted onto said second communications system;

means for writing a functional address corresponding said multicast address into a second frame and for transmitting said second frame onto said second communications system;

means for receiving said second frame on said second communications system and for forwarding said frame onto a third communications system,

means responsive to said functional address for recovering said multicast address and for placing said multicast address in a third frame, and for transmitting said third frame onto said third communications system.

15. The apparatus as in claim 14 wherein said third communications system is an industry standard Ethernet system.

16. The apparatus as in claim 14 wherein said third communications system is an ethernet system based upon an IEEE 802.3 standard.

17. The apparatus as in claim 14 wherein said third communications system is a token ring based upon a Fiber Distributed Data Interface ANSI/IEEE FDDI (ISO 9314) standard.

18. A connection apparatus for computer communications systems comprising:

a first communications system;

a second communications system;

a third communications system;

means for receiving at least one first frame from said first communications system, said at least one first frame having a multicast destination address, said multicast destination address requiring said at least one first frame to be transmitted onto said second communications system;

means for writing a functional address corresponding to said multicast address into a second frame and for transmitting said second frame onto said second communications system;

means for receiving said second frame on said second communications system;

means, responsive to said functional address for recovering said multicast address and for placing said multicast address in a third frame, and for transmitting said third frame onto said third communications system.