Method for establishing restricted broadcast groups in a switched network

• US 6,147,995 A
• Filed: 08/31/1999
• Issued: 11/14/2000
• Est. Priority Date: 11/15/1995
• Status: Expired due to Term

• Current Assignee: Extreme Networks, Inc.
• Original Assignee: Cabletron Systems Incorporated (Extreme Networks, Inc.)
• Inventors: Andlauer, Phil, Dobbins, Kurt, Skubisz, Michael
• Primary Examiner(s): Ton, Dang
• Assistant Examiner(s): Sam, Phirin
• Application Number:
  US09/387,317
• Time in Patent Office: 441 Days
• Field of Search: 370/392, 370/390, 370/396, 370/389, 370/400, 370/401, 370/402, 370/403, 370/404, 370/432, 370/469, 370/474, 370/386, 370/388, 370/395, 370/397, 370/398, 370/399, 370/405 , 370/406, 370/409, 370/420, 370/422, 370/437
• US Class Current: 370/392
• CPC Class Codes: H04L 12/18 for broadcast or conference , e.g. multicast
• CPC Class Codes: H04L 12/1877 Measures taken prior to transmission
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 12/46 Interconnection of networks
• CPC Class Codes: H04L 12/4641 Virtual LANs, VLANs, e.g. virtual private networks [VPN] LAN interconnection over a bridge based backbone H04L12/462; encapsulation techniques H04L12/4633; routing of packets H04L45/00; packet switches H04L49/00; virtual private networks for security H04L63/0272
• CPC Class Codes: H04L 12/467 Arrangements for supporting untagged frames, e.g. port-based VLANs
• CPC Class Codes: H04L 2212/00 Encapsulation of packets
• CPC Class Codes: H04L 41/0213 Standardised network management protocols, e.g. simple network management protocol [SNMP]
• CPC Class Codes: H04L 41/40 using virtualisation of network functions or resources, e.g. SDN or NFV entities
• CPC Class Codes: H04L 45/04 Interdomain routing, e.g. hierarchical routing
• CPC Class Codes: H04L 45/16 Multipoint routing
• CPC Class Codes: H04L 45/24 Multipath
• CPC Class Codes: H04L 45/34 Source routing
• CPC Class Codes: H04L 49/201 Multicast operation; Broadcast operation
• CPC Class Codes: H04L 49/351 for local area network [LAN], e.g. Ethernet switches
• CPC Class Codes: H04L 49/354 for supporting virtual local area networks [VLAN]

Abstract

Method and apparatus for establishing restricted broadcast groups in a switched network. The method assigns different virtual LAN identifiers (VLAN-IDs) to different subsets of associated end systems or access ports. Tables are maintained for mapping the VLAN-IDs with associated end systems and access ports. When a broadcast packet is received at a first switch, it is encapsulated with a VLAN header, including the VLAN-IDs, and sent out a multicast channel to all other switches in the network (domain). The original packet is sent out the other access ports of the receiving switch for the designated VLAN-IDs. The switches receiving the VLAN packet remove the header and send the original packet out access ports associated with the VLAN-IDs extracted from the header. The method provides a mechanism for forwarding broadcast packets of a protocol not supported by the switching mechanism, as well as multicast packets and unicast packets from undiscovered end systems.

Claims

1. A computer-readable storage medium comprising program instructions for restricting flooding of a data packet, of one of a broadcast, multicast and unknown destination type, in a switched data communications network, the network including a plurality of end systems and switches connected by links, the switches having access ports connected to end systems and network ports connected to other switches, the program instructions causing the network to:

a. assign at least one identifier to a respective subset of end systems;

b. map the at least one assigned identifier to an access port attached to at least one end system in the respective subset of end systems; and

c. when the data packet is received from a source end system at a receiving access port of a first switch;

i) determine one or more identifiers associated with the source end system;

ii) encapsulate the data packet by adding a header with the one or more determined identifiers;

iii) forward the encapsulated data packet to all or a subset of other switches in the network; and

iv) determine if at least one access port other than the receiving access port on the first switch is associated with the one or more determined identifiers and forward the data packet out the at least one determined access port.

2. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

d. when the encapsulated data packet is received at a second switch with access ports;

i) strip the header from the encapsulated data packet and to determine the one or more encapsulated identifiers in the header of the encapsulated data packet;

ii) determine if at least one access port of the second switch is associated with the one or more encapsulated identifiers; and

iii) forward the data packet out the at least one determined access port of the second switch.

3. The computer-readable storage medium as recited in claim 2, further comprising instructions to cause the network to:

listen to end systems heard on respective access ports at each switch and to maintain the end systems heard and their respective access ports in a mapping table at the respective switch; and

upon receipt of a unicast packet for a destination end system unknown to the first switch, complete step c for the unicast packet and then at the next switch review the mapping table for the respective access port for the destination end system and forward the packet out the respective access port.

4. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to, if in step c(iv) no other access port is determined, discard the data packet.

5. The computer-readable storage medium as recited in claim 1, further comprising, in step b, instructions to cause the network to:

maintain a first table in each switch to relate the at least one assigned identifier to the end systems or access ports of the respective switch; and

maintain a second table in each switch to relate the access ports of the respective switch to assigned identifiers.

6. The computer-readable storage medium as recited in claim 5, further comprising, in step c.i), instructions to cause the network to:

review the first table for the one or more identifiers associated with the source end system or the receiving access port.

7. The computer-readable storage medium as recited in claim 6, further comprising, in step c.iv), instructions to cause the network to:

review the second table for an access port associated with the one or more determined identifiers.

8. The computer-readable storage medium as recited in claim 7, wherein the assigned identifier is a virtual LAN identifier.

9. The computer-readable storage medium as recited in claim 1,wherein the received data packet is of a protocol not supported by a protocol-specific call processor in the first switch.

10. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain a common registry of assigned identifiers.

11. The computer-readable storage medium as recited in claim 10, further comprising instructions to cause the network to:

register each end system or access port with the common registry, and

return a list of assigned identifiers from the common registry to each switch for the end systems or access ports of the respective switch.

12. The computer-readable storage medium as recited in claim 10, further comprising instructions to cause the network to:

send a signal from the first switch to the common registry to resolve an end system or access port to its assigned identifiers.

13. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain the mapping at each switch for the end system or access ports of the respective switch.

14. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

prior to assigning an identifier to a specific end system or access port, maintain a default identifier for that specific end system or access port which maps to predetermined access ports.

15. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain a multicast channel of connections between all or a subset of switches and wherein step c(iii) comprises forwarding the encapsulated packet on the multicast channel.

16. The computer-readable storage medium as recited in claim 15, wherein the channel includes:

a point-to-multipoint connection from each switch to all other switches in the network.

17. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network, at step c(iii), to provide a distributed service in the switches for forwarding the encapsulated data packet.

18. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to assign the identifier based on a policy work group definition.

19. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain at least one mapping table at each switch for performing the mapping step.

20. The computer-readable storage medium as recited in claim 19, further comprising instructions to cause the network to:

listen to end systems heard on respective access ports at each switch and maintain the end systems heard and their respective access ports in the mapping table at the respective switch.

21. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

assign a reserved identifier without limitation as to end system and access port.

22. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain a Management Information Base (MIB) interface at each switch for programming at least one mapping table, the mapping table being used to perform the mapping step.

23. The computer-readable storage medium as recited in claim 22, further comprising instructions to cause the network to:

use a Simple Network Management Protocol (SNMP) set message to maintain the mapping table at each switch.

24. The computer-readable storage medium as recited in claim 1, further comprising instructions to cause the network to:

maintain a status table at each switch to enable and disable a respective subset.

25. A computer-readable storage medium comprising program instructions for restricting flooding of a data packet, of one of a broadcast, multicast and unknown destination type, in a switch to be used in a switched data communications network, the network to include end systems and switches connected by links, the switches having access ports connected to end systems and network ports connected to other switches, the program instructions causing the switch to:

a. assign at least one identifier to a respective subset of end systems;

b. map the at least one assigned identifier to an access port attached to at least one end system in the respective subset of end systems; and

c. when the data packet is received from a source end system at a receiving access port of the switch;

i) determine one or more identifiers associated with the source end system;

ii) encapsulate the data packet by adding a header with the one or more determined identifiers;

iii) forward the encapsulated data packet to all or a subset of other switches in the network; and

iv) determine if at least one access port other than the receiving access port on the switch is associated with the one or more determined identifiers and forward the data packet out the at least one determined access port.

26. The computer-readable storage medium as recited in claim 25, further comprising instructions to cause the switch to:

d. when an encapsulated data packet is received;

i) strip the header from the encapsulated data packet and determine the one or more encapsulated identifiers in the header of the encapsulated data packet;

ii) determine if at least one access port of the switch is associated with the one or more encapsulated identifiers; and

iii) forward the data packet out the at least one determined access port of the switch.

27. The computer-readable storage medium as recited in claim 26, further comprising instructions to cause the switch to:

listen to end systems heard on the access ports and to maintain the end systems heard and their respective access ports in a mapping table.

28. The computer-readable storage medium as recited in claim 25, further comprising instructions to cause the switch to, if in step c(iv) no other access port is determined, discard the data packet.

29. The computer-readable storage medium as recited in claim 25, further comprising, in step b, instructions to cause the switch to:

maintain a first table to relate the at least one assigned identifier to the end systems or access ports of the switch; and

maintain a second table to relate the access ports of the switch to assigned identifiers.

30. The computer-readable storage medium as recited in claim 29, further comprising, in step c.i), instructions to cause the switch to:

review the first table for the one or more identifiers associated with the source end system or the receiving access port.

31. The computer-readable storage medium as recited in claim 30, further comprising, in step c.iv), instructions to cause the switch to:

review the second table for an access port associated with the one or more determined identifiers.

32. The computer-readable storage medium as recited in claim 25, further comprising instructions to cause the switch to:

prior to assigning an identifier to a specific end system or access port, maintain a default identifier for that specific end system or access port which maps to predetermined access ports.

33. The computer-readable storage medium as recited in claim 25, further comprising instructions to cause the switch to:

maintain a Management Information Base (MIB) interface.

34. The computer-readable storage medium as recited in claim 33, further comprising instructions to cause the switch to:

use a Simple Network Management Protocol (SNMP) message to maintain a mapping table.

35. The computer-readable storage medium as recited in claim 25, further comprising instructions to cause the switch to:

maintain a status table to enable and disable a respective subset.