Multicast bandwidth multiplication for a unified distributed switch

• US 8,897,301 B2
• Filed: 03/14/2012
• Issued: 11/25/2014
• Est. Priority Date: 03/14/2012
• Status: Expired due to Fees

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Basso, Claude, Greenfield, Todd A., Hillier, Philip R. III, Rudquist, Mark L., Valk, Kenneth M., Vanderpool, Brian T., Walk, Bruce M.
• Primary Examiner(s): Cho, Un C
• Assistant Examiner(s): Lou, Peian
• Application Number:
  US13/420,180
• Publication Number:
  US 20130242985A1
• Time in Patent Office: 986 Days
• Field of Search: 370/230, 370/389, 370/390, 370/394, 370/395.1, 370/396, 370/400, 370/401, 370/402, 370/424, 370/428, 370/438, 709213-217
• US Class Current: 370/390
• CPC Class Codes: H04L 45/16 Multipoint 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 49/70 Virtual switches

Abstract

The distributed switch may include a plurality of chips (i.e., sub-switches) on a switch module. These sub-switches may receive from a computing device connected to a Tx/Rx port a multicast data frame (e.g., an Ethernet frame) that designates a plurality of different destinations. Instead of simply using one egress connection interface to forward the copies of the data frame to each of the destinations sequentially, the sub-switch may use a plurality of a connection interfaces to transfer copies of the multicast data frame simultaneously. The port that receives the multicast data frame can borrow the connection interfaces (and associated hardware such as buffers) assigned to these other ports to transmit copies of the multicast data frame simultaneously.

Claims

1. A computer program product comprising:

a non-transitory computer-readable storage medium having computer-readable program code embodied therewith, the computer-readable program code comprising computer-readable program code configured to;

receive a multicast data frame on a first port of a networking element, wherein the multicast data frame is an Ethernet frame;

store at least a portion of the multicast data frame in each buffer of a first plurality of buffers, wherein the portion of the multicast data frame is at least a portion of a payload of the Ethernet frame, and wherein at least one of the first plurality of buffers is assigned to a second input port of the networking element;

store a respective header corresponding to each of the portions of the multicast data frame in a second plurality of buffers, wherein at least one of the second plurality of buffers is assigned to the second input port;

combining each of the portions of the received multicast data frame with the corresponding header to generate data packets; and

separately forward each of the data packets based on the respective headers via respective output connection interfaces of the networking element, wherein a first one of the output connection interfaces is assigned to the first input port and a second one of the output connection interfaces is assigned to the second input port, wherein the first input port borrows the at least one buffer of the first plurality of buffers, the at least one buffer of the second plurality of buffers, and the respective output connection interface assigned to the second input port.

2. The computer program product of claim 1, wherein the networking element stores the portion of the received multicast data frame in each of the first plurality of buffers in a single transfer.

3. The computer program product of claim 2, wherein storing the portion in a single transfer further comprises transmitting the portion of the received multicast data frame on a bus that is shared by the first plurality of buffers.

4. The computer program product of claim 1, wherein a combined bandwidth of the output connection interfaces is approximately a multiple of a bandwidth of the first input port.

5. The computer program product of claim 1, wherein, after forwarding the data packets, at least one of the portions is not evicted from the first plurality of buffers, further comprising computer-readable program code configured to, after forwarding the data packets:

storing a replacement header for one of the non-evicted portions, wherein the replacement header comprises a different destination than an original header that was previously assigned to the one non-evicted portion; and

forwarding the one non-evicted portion and the replacement header.

6. The computer program product of claim 1, further comprising computer-readable program code configured to:

divide a payload of the multicast data frame into a plurality of data chunks, wherein the portion of the received multicast data frame is one of the data chunks;

store each of the data chunks into each of the first plurality of buffers; and

store headers corresponding to each of the data chunks in the second plurality of buffers, wherein the headers comprise of sequence information that defines an order of data chunks that correspond to the payload of the multicast data frame.

7. A networking element for forwarding a multicast data frame, comprising:

a first port that receives a multicast data frame, wherein the multicast data frame is an Ethernet frame;

a first plurality of buffers, wherein at least a portion of the multicast data frame is stored in each buffer of the first plurality of buffers, wherein the portion of the multicast data frame is at least a portion of a payload of the Ethernet frame, and wherein at least one of the first plurality of buffers is assigned to a second input port of the networking element;

a second plurality of buffers that store a header corresponding to each of the portions of the multicast data frame, wherein at least one of the second plurality of buffers is assigned to the second input port, wherein the networking element is configured to combine each of the portions of the first received multicast data frame with the corresponding header to generate data packets; and

respective output connection interfaces configured to separately forward the data packets based on respective headers, wherein a first one of the output connection interfaces is assigned to the first input port and a second one of the output connection interfaces is assigned to the second input port, wherein the first input port borrows the at least one buffer of the first plurality of buffers, the at least one buffer of the second plurality of buffers, and the respective output connection interface assigned to the second input port.

8. The networking element of claim 7, wherein the portion of the received multicast data frame is stored in each of the first plurality of buffers in a single transfer.

9. The networking element of claim 8, further comprising a bus that is shared by the first plurality of buffers, wherein storing the portion in a single transfer further comprises transmitting the portion of the received multicast data frame on the bus.

10. The networking element of claim 7, wherein a combined bandwidth of the output connection interfaces is approximately a multiple of a bandwidth of the first input port.

12. The networking element of claim 7, wherein a payload of the multicast data frame is divided into a plurality of data chunks, wherein the portion of the received multicast data frame is one of the data chunks,

wherein each of the data chunks is stored into each of the first plurality of buffers, and

wherein headers corresponding to each of the data chunks are stored in the second plurality of buffers, wherein the headers comprise of sequence information that defines an order of data chunks that correspond to the payload of the multicast data frame.

11. A networking element for forwarding a multicast data frame, comprising:

a first input port that receives the multicast data frame;

a first plurality of buffers, wherein at least a portion of the multicast data frame is stored in each of the first plurality of buffers, wherein at least one of the first plurality of buffers is assigned to a second input port of the networking element;

a second plurality of buffers that store a header corresponding to each of the portions of the multicast data frame, wherein at least one of the second plurality of buffers is assigned to the second input port; and

respective output connection interfaces configured to separately forward each of a plurality of the portions of the received multicast data frame stored in the first plurality of buffers based on respective headers, wherein a first one of the output connection interfaces is assigned to the first input port and a second one of the output connection interfaces is assigned to the second input port, wherein the first input port borrows the at least one buffer of the first plurality of buffers, the at least one buffer of the second plurality of buffers, and the respective output connection interface assigned to the second input port,

wherein, after forwarding the portions of the received multicast data frame, the networking element is configured to not evict at least one of the portions from the first plurality of buffers, wherein, after forwarding the portions;

the networking element is configured to store a replacement header for one of the non-evicted portions in one of the second plurality of buffers, wherein the replacement header comprises a different destination that an original header that was previuously assigned to the one non-evicted portion; and

the networking element is configured to forward the one non-evicted portion and the replacement header.