Why I have to increase MAXBIGPKTS to make the UDP transfer

Hello Xishan,

i am not come up with solution ...rather i am struggeling with same problem. i am not able to receive more then 1464 charactor through UDP based client server application ....my server (on linux machine ) send's 7 packet of UDP data each having 1464 charactor but my client (nios-II) won't accept more then one packet....

my application stack size is 1024,

could you please help me out

kaushal

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Hello everyone,

I am now doing a data transfer work based on StratixII NiosII development kit RoHS board. It is a very simple one which read data from a FIFO outside NiosII core. The data are sent to computer through on-board Ethernet LAN91C111 by UDP protocol.

The data transfer cycle is as this:

read data from FIFO -> store in DRAM -> transfer to computer.

The package size of UDP is 1468 Bytes. The problem is, when I use default MAXBIGPKTS value (30) in ipport.h, it will give me errors (error# is 105 which said I do not have enough buffer) after few cycles. I have to increase MAXBIGPKTS value to 3500 to eliminate the error but the memory and performance are suffered due to this.

My niosII cpu core run at 150Mhz speed with data and instruction cache size both 64KB. Now the UDP transfer rate is about 22Mbits/s. According to others design (such as Ethernet_Accel_Design by Altera), they really don't need to increase MAXBIGPKTS value. Do you have any suggestion for me? Thank you very much.

Xishan

p.s. I am now using Quartus II 9.1sp1.

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