Method, device and system for implementing multicast forwarding in extended VLAN bridge

• US 20130094506A1
• Filed: 03/18/2011
• Published: 04/18/2013
• Est. Priority Date: 06/08/2010
• Status: Active Grant

• Current Assignee: ZTE Corporation
• Original Assignee: ZTE Corporation
• Inventors: Song, Xiaoli
• Granted Patent: US 9,049,138 B2
• Time in Patent Office: Days
• US Class Current: 370/390
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• 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 45/16 Multipoint routing

Abstract

The disclosure provides a method, a device, and a system for implementing multicast forwarding in an EVB, wherein the method includes: the EVB controlling bridge receives a multicast frame and acquires a multicast address from the multicast frame; inquires on a master port and an ID of a subgroup corresponding to the multicast address from a first preset mapping table; forwards, when the ID of the corresponding subgroup is an MCID, the multicast frame carrying the MCID to a corresponding PE assembly via the master port; and the PE assembly distributes the multicast frame to a UE according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly. In the present disclosure, the same multicast frame is forwarded just once at the same physical port in the EVB according to the mapping relation between the multicast address in the multicast frame and the master port and the ID of the subgroup corresponding to the multicast address, avoiding waste of network bandwidth caused by repetitive duplicating and forwarding by the same physical port, and increasing network bandwidth utilization.

Claims

1. A method for implementing multicast forwarding in an Extended VLAN Bridge (EVB), comprising:

receiving a multicast frame and acquiring a multicast address from the multicast frame;

inquiring on a master port and an identifier (ID) of a subgroup corresponding to the multicast address from a first preset mapping table;

forwarding, when the ID of the corresponding subgroup is a Multicast Identifier (MCID), the multicast frame carrying the MCID to a corresponding Port Extender (PE) assembly via the master port; and

distributing, by the PE assembly, the multicast frame to a User Equipment (UE) according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly.

2. The method according to claim 1, wherein forwarding, when the ID of the corresponding subgroup is an MCID, the multicast frame carrying the MCID to a corresponding PE assembly via the master port comprises:

carrying the MCID in the multicast frame when the ID of the corresponding subgroup is the MCID; and

forwarding via the master port the multicast frame carrying the MCID to a physical port corresponding to the master port and sending via the physical port the multicast frame carrying the MCID to the corresponding PE assembly.

12. The method according to claim 2, wherein distributing, by the PE assembly, the multicast frame to a UE according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly comprises:

receiving, by the PE assembly, the multicast frame carrying the MCID via an uplink port;

inquiring on a second preset mapping table, duplicating and forwarding the multicast frame levelwise according to a correspondence between the MCID carried in the multicast frame and a PE downlink port in the second preset mapping table;

stripping the MCID from the multicast frame when the multicast frame is forwarded to an external port between the PE assembly and the UE; and

sending the multicast frame stripped of the MCID to the UE via the external port.

13. The method according to claim 12, further comprising:

before receiving a multicast frame and acquiring a multicast address from the multicast frame,

establishing the first preset mapping table for the mapping relation between the multicast address and the master port and the ID of the corresponding subgroup; and

establishing the second preset mapping table for the correspondence between the MCID and the PE downlink port.

14. The method according to claim 13, further comprising:

before inquiring on a master port and an ID of a subgroup corresponding to the multicast address from a first preset mapping table,

sending, when the ID of the corresponding subgroup is a Customer VLAN Identifier (CVID), the multicast frame to the UE via an external port corresponding to the CVID.

3. The method according to claim, wherein distributing, by the PE assembly, the multicast frame to a UE according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly comprises:

receiving, by the PE assembly, the multicast frame carrying the MCID via an uplink port;

inquiring on a second preset mapping table, duplicating and forwarding the multicast frame levelwise according to a correspondence between the MCID carried in the multicast frame and a PE downlink port in the second preset mapping table;

stripping the MCID from the multicast frame when the multicast frame is forwarded to an external port between the PE assembly and the UE; and

sending the multicast frame stripped of the MCID to the UE via the external port.

4. The method according to claim 3, further comprising:

before receiving a multicast frame and acquiring a multicast address from the multicast frame,

establishing the first preset mapping table for the mapping relation between the multicast address and the master port and the ID of the corresponding subgroup; and

establishing the second preset mapping table for the correspondence between the MCID and the PE downlink port.

5. The method according to claim 4, further comprising:

before inquiring on a master port and an ID of a subgroup corresponding to the multicast address from a first preset mapping table,

sending, when the ID of the corresponding subgroup is a Customer VLAN Identifier (CVID), the multicast frame to the UE via an external port corresponding to the CVID.

6. A device for implementing multicast forwarding in an Extended VLAN Bridge (EVB), comprising a receiving module, an inquiring module, a forwarding module and a distributing module, wherein

the receiving module is configured to receive a multicast frame, acquire a multicast address from the multicast frame, and send the multicast address to the inquiring module;

the inquiring module is configured to inquire on a master port and an identifier (ID) of a subgroup corresponding to the multicast address from a first preset mapping table and send an inquired result to the forwarding module;

the forwarding module is configured to forward, when the ID of the corresponding subgroup is a Multicast Identifier (MCID), the multicast frame carrying the MCID to a corresponding Port Extender (PE) assembly via the master port; and

the distributing module is located in the PE assembly and is configured to distribute the multicast frame to a User Equipment (UE) according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly.

7. The device according to claim 6, wherein the forwarding module comprises a carrying unit and a first sending unit, wherein

the carrying unit is configured to carry the MCID in the multicast frame when the ID of the corresponding subgroup in the inquired result is the MCID;

and

the first sending unit is configured to forward via the master port the multicast frame carrying the MCID to a physical port corresponding to the master port and send via the physical port the multicast frame carrying the MCID to the corresponding PE assembly.

8. The device according to claim 6, wherein the distributing module comprises a receiving unit, an inquiring unit, a forwarding unit, a stripping unit and a second sending unit, wherein

the receiving unit is configured to receive the multicast frame carrying the MCID via an uplink port;

the inquiring unit is configured to inquire on a second preset mapping table;

the forwarding unit is configured to duplicate and forward the multicast frame levelwise according to a correspondence between the MCID carried in the multicast frame and a PE downlink port in the second preset mapping table;

the stripping unit is configured to strip the MCID from the multicast frame when the multicast frame is forwarded to an external port between the PE assembly and the UE; and

the second sending unit is configured to send the multicast frame stripped of the MCID to the UE via the external port.

9. The device according to claim 8, further comprising:

an establishing module configured to establish the first preset mapping table for the mapping relation between the multicast address and the master port and the ID of the corresponding subgroup, send the first preset mapping table to the inquiring module, establish the second preset mapping table for the correspondence between the MCID and the PE downlink port, and send the second preset mapping table to the distributing module.

10. The device according to claim 9, wherein the forwarding module is further configured to send, when the ID of the corresponding subgroup is a Customer VLAN Identifier (CVID), the multicast frame to the UE via an external port corresponding to the CVID.

15. The device according to claim 7, wherein the distributing module comprises a receiving unit, an inquiring unit, a forwarding unit, a stripping unit and a second sending unit, wherein

the receiving unit is configured to receive the multicast frame carrying the MCID via an uplink port;

the inquiring unit is configured to inquire on a second preset mapping table;

the forwarding unit is configured to duplicate and forward the multicast frame levelwise according to a correspondence between the MCID carried in the multicast frame and a PE downlink port in the second preset mapping table;

the stripping unit is configured to strip the MCID from the multicast frame when the multicast frame is forwarded to an external port between the PE assembly and the UE; and

the second sending unit is configured to send the multicast frame stripped of the MCID to the UE via the external port.

16. The device according to claim 15, further comprising:

an establishing module configured to establish the first preset mapping table for the mapping relation between the multicast address and the master port and the ID of the corresponding subgroup, send the first preset mapping table to the inquiring module, establish the second preset mapping table for the correspondence between the MCID and the PE downlink port, and send the second preset mapping table to the distributing module.

17. The device according to claim 16, wherein the forwarding module is further configured to send, when the ID of the corresponding subgroup is a Customer VLAN Identifier (CVID), the multicast frame to the UE via an external port corresponding to the CVID.

11. A system for implementing multicast forwarding, comprising:

an Extended VLAN Bridge (EVB) and a User Equipment (UE) connected with an external port of the EVB, wherein the EVB comprises a device for implementing multicast forwarding, and the device for implementing multicast forwarding comprises a receiving module, an inquiring module, a forwarding module, and a distributing module, wherein

the receiving module is configured to receive a multicast frame, acquire a multicast address from the multicast frame, and send the multicast address to the inquiring module;

the inquiring module is configured to inquire on a master port and an identifier (ID) of a subgroup corresponding to the multicast address from a first preset mapping table and send an inquired result to the forwarding module;

the forwarding module is configured to forward, when the ID of the corresponding subgroup is a Multicast Identifier (MCID), the multicast frame carrying the MCID to a corresponding Port Extender (PE) assembly via the master port; and

the distributing module is located in the PE assembly and is configured to distribute the multicast frame to the UE according to a correspondence between the MCID carried in the multicast frame and a downlink port of the PE assembly.