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Altera_Forum
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15 years ago

Altera TSE driver and example program for lwIP (1.3.2)

After many many requests and complaints about lack of support and/or documentation for support of lwIP for the Altera TSE, I have developed a drop-in TSE driver and example program and made this avai...
Altera_Forum's avatar
Altera_Forum
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13 years ago

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Hmm, lets see:

TCP_MSS = 1460

PBUF_LINK_HLEN = 14

ETH_PAD_SIZE = 2

To sum up: 1460+40+14+2 = 1516

Seems like no problems here?

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Lets see again :)

In the code DipSwitch posted on January 19th TCP_MSS is defined through the chain: 


add_sw_setting decimal_number system_h_define memory.mem_size CONF_LWIP_MEM_SIZE 32768 "Size of the memory poll"# define MEM_SIZE    CONF_LWIP_MEM_SIZE# define TCP_WND         (MEM_SIZE / 8)# define TCP_MSS         (TCP_WND / 4)
With all defaults TCP_MSS = 1024. In any case, I think you should agree, that “Ethernet frame length” is completely unrelated to “the size of the heap memory”, or “TCP Maximum segment size”, or “The size of a TCP window”. Mixing all this together misleading for user. For example, I spent last day debugging strange hangs in my code, which occurred irregularly after from 40 seconds to 1 hour of successful execution. That code doesn’t need much lwIP memory and doesn’t use TCP at all!