Parallel switching architecture for multiple input/output
View Patent ↗A multiple input/output-queued(MIOQ) switch is presented. This MIOQ switch comprises a (k,m)-dimensional crossbar fabric having k ingress lines and m egress lines; N input buffers at each input; M output buffers at each output; N×k interconnection networks each of which is able to move a packet from each input to one of the k egress lines; and m×M interconnection networks each of which is able to move the arrived packet at output from the m egress lines to one of the M(wherein M is m or N) output buffers. The multiple input/output-queued(MIOQ) switch according to the present invention requires no “speed-up”. Performance matches the performance of an output-queued switch.
1. A multiple input/output-queued switch of which size is N comprising:
a (k,m)-dimensional crossbar fabric having k ingress lines at each input and m egress lines at each output;
N input buffers at each input;
M output buffers at each output;
N×k interconnection networks each of which is able to move up to k packets from the N input buffers to the k ingress lines; and
m×M interconnection networks each of which is able to move up to m packets arrived at each output from the m egress lines to the M (wherein M is equal to or more than m) output buffers.
2. The multiple input/output-queued switch according to claim 1 , which further comprises a scheduler which includes multi-token-based arbiters which select multiple requests (or grants) using multiple tokens.
3. The multiple input/output-queued switch according to claim 2 , wherein the multi-token-based arbiter with k (or m) tokens includes log {2}k (or log {2}m) control lines and N modules.
4. The multiple input/output-queued switch according to claim 3 , wherein the multi-token-based arbiter has multiple tokens which together pass the modules every clock, and one of the multiple tokens is grabbed by a module which has a request.
5. The multiple input/output-queued switch according to claim 2 , wherein the multi-token-based arbiter has timely-distributed tokens.
6. The multiple input/output-queued switch according to claim 5 , wherein a certain module has all tokens, the module emits the tokens one by one every clock, and one of the tokens is grabbed by a module which has a request.
7. The multiple input/output-queued switch according to claim 2 , wherein the multi-token-based arbiter has spatially-distributed tokens.
8. The multiple input/output-queued switch according to claim 7 , wherein the tokens are initially distributed to the selected modules, the distributed tokens pass the modules independently clock by clock, and the token is grabbed by a module which has a request.
9. The multiple input/output-queued switch according to claim 1 , wherein, according to the discipline of FIFO(First Input First Output), the packets delivered to the output are stored at the output buffers in a round-robin manner in order to maintain the sequence of packets, and then sent to the external output.
10. The multiple input/output-queued switch according to claim 2 , wherein the number of tokens in multi-token-based arbiter corresponding to each input or output is configured to be same as the number of corresponding ingress lines or egress lines if the switch is asymmetric one wherein the number of ingress lines (in case of input port) or egress lines (in case of output port) are not identical for each port.
11. The multiple input/output-queued switch according to claim 10 , wherein the bandwidth of each input or output of the asymmetric switch is determined by the number of ingress lines or egress lines.
12. The multiple input/output-queued switch according to claim 1 , wherein the (k,m)-dimensional crossbar fabric is implemented by connecting crossbar fabrics whose size is smaller than that of the (k,m)-dimensional crossbar fabric linearly.
13. The multiple input/output-queued switch according to claim 1 , wherein the (k,m)-dimensional crossbar fabric is implemented based on a decomposing method.
14. The multiple input/output-queued switch(MIOQ) according to claim 13 , wherein virtual output queueings at the input of the MIOQ are divided into k groups, k groups of multiple buffers at the output of the MIOQ are further divided into k×k groups, and an N/k×N/k switch is allocated to each group.
15. The multiple input/output-queued switch according to claim 1 , which operates at a slower rate than external input rate.
16. The multiple input/output-queued switch according to claim 1 , wherein N input buffers are implemented as a redundant buffer.
17. The multiple input/output-queued switch according to claim 16 , wherein each memory space is allocated logically for N buffers, the memory addresses for the start and the end point of each buffer are memorized separately, and all the memories changes the values of pointers to new values of addresses that indicate the next packet if a packet is transmitted.