Multicasting apparatus and method in shared memory switch

A multicasting method in a shared memory switch, the method comprising:

• (a) storing a pointer indicating an address in which data is stored in an input subqueue and forwarding the same to an output subqueue based on an output port bitmap and a class of the data, wherein when the data is multicast data, the same pointer is duplicated to be forwarded to a plurality of output subqueues;
• and
• (b) selecting one bit for the data read out of the input subqueue at a time to create a bitmap stream selected only one bit, when the pointer is forwarded from the input subqueue to the corresponding output subqueue, wherein in case ready data is presented in the input subqueue, the data stored in the input subqueue is read out before being processed all data, thereby preventing a waiting time between data of the input subqueue from being occurred.

A multicasting method in a shared memory switch, wherein a final number by which each address is to be read out for multicasting is stored in the addresses of a first predetermined memory;

• a number reading out a corresponding address at a time in a second predetermined memory distinct from the first predetermined memory, allowing a read value to be increased at each instant of the reading of the corresponding address of the shared memory, wherein the increased value is compared with the final number;
• if the increased value is less than the final number, the increased value is increased by one;
• and if the increased value is equal to the final number, the increased value is set to be zero, thereby allowing the address of the shared memory to be returned to an unused address list.

A computer-readable medium storing a program for implementing functions comprising:

• (a) storing a pointer indicating an address in which data is stored in an input subqueue and forwarding the same to an output subqueue based on an output port bitmap and a class of the data, wherein when the data is multicast data, the same pointer is duplicated to be forwarded to a plurality of output subqueues;
• and
• (b) selecting one bit for the data read out of the input subqueue at a time to create a bitmap stream selected only one bit, when the pointer is forwarded from the input subqueue to the corresponding output subqueue, wherein in case ready data is presented in the input subqueue, the data stored in the input subqueue is read out before being processed all data, thereby preventing a waiting time between data of the input subqueue from being occurred.

A computer-readable medium storing a program for implementing a function in which a final number by which each address is to be read out for multicasting is stored in the addresses of a first predetermined memory;

• a number reading out a corresponding address at a time is stored in a second predetermined memory distinct from the first predetermined memory, allowing a read value to be increased at each instant of the reading of the corresponding address of the shared memory, wherein the increased value is compared with the final number;
• if the increased value is less than the final number, the increased value is increased by one;
• and if the increased value is equal to the final number, the increased value is set to be zero, thereby allowing the address of the shared memory to be returned to an unused address list.