Memory load balancing for single stream multicast

• US 7,292,529 B1
• Filed: 07/31/2002
• Issued: 11/06/2007
• Est. Priority Date: 07/31/2002
• Status: Expired due to Fees

• Current Assignee: Juniper Networks Incorporated
• Original Assignee: Juniper Networks Incorporated
• Inventors: Basu, Debashis, Godbole, Avanindra, Libby, Jeffrey Glenn, Lim, Raymond M.
• Primary Examiner(s): HSU, ALPUS
• Application Number:
  US10/208,008
• Time in Patent Office: 1,924 Days
• Field of Search: 370/230, 370/390, 370/412, 370/432, 370/474
• US Class Current: 370/230
• CPC Class Codes: H04L 12/1886 with traffic restrictions for efficiency improvement, e.g. involving subnets or subdomains
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 47/125 by balancing the load, e.g. traffic engineering
• CPC Class Codes: H04L 47/36 by determining packet size, e.g. maximum transfer unit [MTU]
• CPC Class Codes: H04L 47/43 Assembling or disassembling of packets, e.g. segmentation and reassembly [SAR]

Abstract

A system for multicasting a packet of data to a single data stream is provided. The system may determine a size of the packet and may send a single copy of the packet if the size of the packet exceeds a threshold value. A number of copies of the packet yet to be multicast may be ascertained if the size of the packet of data does not exceed the threshold value. Copies of the packet may be transmitted based on the number of copies of the packet yet to be multicast.

Claims

1. A method for multicasting a packet of data to a single data stream, comprising:

determining whether the packet is to be sent once or multicast;

transmitting the packet if the packet is to be sent once; and

if the packet is to be multicast, then;

determining a size of the packet,

sending a single copy of the packet if the size of the packet exceeds a size threshold value,

ascertaining a number of copies of the packet yet to be multicast if the size of the packet does not exceed the size threshold value, and

transmitting copies of the packet based on the number of copies of the packet yet to be multicast.

2. The method of claim 1, further comprising:

decrementing the number of copies of the packet yet to be multicast by a number of copies of the packet transmitted.

3. The method of claim 1, further comprising:

transmitting a single packet of data if the number of copies of the packet yet to be multicast is one.

4. The method of claim 1, wherein said transmitting copies of the packet includes:

transmitting a first number of copies of the packet if the number of copies of the packet yet to be multicast is greater than a count threshold.

5. The method of claim 4, wherein said transmitting copies of the packet includes:

transmitting a second number of copies of the packet of data if the number of packets yet to be multicast is less than or equal to the count threshold.

6. The method of claim 1, wherein said sending a single copy of the packet includes:

reading a plurality of units of data and a data structure out of a memory, and

assembling the single packet from the plurality of units of data and the data structure.

7. The method of claim 1, wherein said transmitting copies of the packet includes:

reading at least one unit of data and a data structure out of a memory,

storing the at least one unit of data and the data structure in a buffer, and

assembling a plurality of copies of the packet from the at least one unit of data and the data structure.

8. The method of claim 1, wherein the threshold value is four units of data.

9. A method for multicasting a packet of data to a single stream of data, comprising:

determining whether the packet is to be sent once or multicast;

transmitting the packet if the packet is to be sent once; and

if the packet is to be multicast, then;

determining whether a number of units of data associated with a packet exceeds a size threshold,

outputting the units of data associated with the packet from a memory,

assembling the units of data into a single packet if the number of units of data exceeds the size threshold, and

forming the units of data into a plurality of packets if the number of units of data does not exceed the threshold.

10. The method of claim 9, further comprising:

assembling the units of data into a single packet if a multicast count of the packet is one.

11. The method of claim 9, further comprising:

decrementing a multicast count associated with the units of data in the memory by a number of packets assembled or formed.

12. The method of claim 9, wherein said forming the units of data into a plurality of packets includes:

forming a first number of packets of data sequentially if a multicast count of the packet is greater than a count threshold.

13. The method of claim 9, wherein said forming the units of data into a plurality of packets includes:

forming a second number of packets of data sequentially if a multicast count of the packet is less than or equal to the count threshold.

14. The method of claim 9, wherein said assembling the units of data into a single packet includes:

outputting a data structure from the memory, and

assembling the single packet from the plurality of units of data and the data structure.

15. The method of claim 9, wherein said forming the units of data into a plurality of packets includes:

outputting at least one unit of data and a data structure out from the memory,

storing the at least one unit of data and the data structure, and

forming the plurality of packets from the stored at least one unit of data and the stored data structure.

16. The method of claim 9, wherein the size threshold is four units of data.

17. A network device comprising:

a memory system including;

packet information memory configured to output packet information including a multicast count, and

data memory configured to output data associated with the packet information; and

a processing unit coupled to the memory system and configured to;

assemble one or more packets of information from the packet information and the data, wherein a number of packets of information assembled from the packet information and the data depend on at least one of a multicast count of the packet information or a size of the data associated with the packet information,

determine whether the packet information is to be sent once or multicast,

transmit the packet information if the packet information is to be sent once, and

assemble one packet of information from the packet information and the data if the size of the data is greater than a threshold value and the packet information is to be multicast.

18. The network device of claim 17, wherein the packet information memory includes:

a plurality of queues respectively configured to store packet information, and

a dequeue engine configured to select the packet information to output from among the queues.

19. The network device of claim 18, wherein the dequeue engine is also configured to determine the size of data in the data memory that is associated with the packet information and to determine the multicast count of the packet information.

20. The network device of claim 17, wherein the data memory includes:

a plurality of banks of memory configured to store the data associated with the packet information.

21. The network device of claim 17, wherein the processing unit is configured to assemble a plurality of packets from the packet information and the data if the size of the data is less than or equal to a threshold value and if the multicast count of the packet information is greater than one.

22. A system for multicasting packets of data, comprising:

means for determining whether the packet is to be sent once or multicast;

means for transmitting the packet if the packet is to be sent once;

means for sending a single copy of the packet if a size of the packet exceeds a threshold value and if the packet is to be multicast;

means for ascertaining a number of copies of the packet yet to be multicast if the size of the packet does not exceed the threshold value and if the packet is to be multicast; and

means for transmitting copies of the packet based on the ascertained number of copies of the packet yet to be multicast and if the packet is to be multicast.

23. A method for multicasting a data structure to a single data stream, comprising:

determining whether the data structure is to be sent once or multicast;

transmitting the data structure if the data structure is to be sent once; and

if the data structure is to be multicast, then;

determining whether a number of units of data exceeds a size threshold,

outputting the units of data from a memory,

assembling the units of data into a single data structure if the number of units of data exceeds the size threshold, and

forming the units of data into a plurality of data structures if the number of units of data does not exceed the size threshold.

24. The method of claim 23, wherein said forming the units of data into a plurality of data structures includes:

forming data structures sequentially if a multicast count associated with the units of data is greater than a count threshold.

25. The method of claim 23, wherein said forming the units of data into a plurality of data structures includes:

forming two data structures sequentially if a multicast count associated with the units of data is less than or equal to the count threshold.