Re: [lwip-users] lwip fails for full duplex communication

[GICINDIA]

My product requirement is serial to Ethernet & vice verse data transmission. 

Full duplex means, i m receiving (Ethernet to Serial)and transmitting
(Serial to Ethernet) data (500kb file)simultaneously on a single PCB
connection, continuously. 

I think problem is in buffer configurations in lwipopts.h file.
current configurations are 
#define MEM_SIZE                        (7 * 1024)
#define MEMP_NUM_TCP_SEG              48 
#define PBUF_POOL_SIZE                16
#define TCP_WND                         2048 
#define TCP_MSS                         1024
#define TCP_SND_BUF                     (6 * 1024)
#define TCP_SND_QUEUELEN              48 
#define PBUF_POOL_BUFSIZE               256

can u plz tell me which buffer size i have set wrong?



Krzysztof Wesołowski wrote:
> 
> On Tue, May 29, 2012 at 10:18 AM, lookwong <address@hidden>
> wrote:
>> I don't think lwip spports full duplex mode.
> 
> I do not know what you mean by full duplex, but LwIP works fine for
> example echoing data, so the problem is probably in application
> 
> Regards,
> Krzysztof Wesołowski,
> tel. +48 721 337 238
> 
> http://www.rainlabs.pl
> 
> 
> 
>>
>>
>> On Tue, May 22, 2012 at 12:36 PM, GICINDIA <address@hidden> wrote:
>>>
>>>
>>> Hello Kieran,
>>>
>>> Thanx alot for the reply.
>>>
>>> If no. of pbufs is the issue then, to resolve this problem can i make
>>> MEMP_NUM_PBUF = 32?
>>>
>>> But, i did not understand lwip data transmit logic fully, if possible
>>> can
>>> u
>>> explain it? so that i can be able to implement some other logic for
>>> buffer
>>> handling at serial side before writing data into pbufs.
>>>
>>>
>>> Regards,
>>> Asma.
>>>
>>>
>>>
>>> Kieran Mansley wrote:
>>> >
>>> > It looks to me like you have 16 pbufs, each of size 256 bytes.  Your
>>> > TCP_WND is 2048, so you can have 2KB of data received and waiting for
>>> > your
>>> > application before the other end will stop sending.  Your TCP_SND_BUF
>>> is
>>> > 6KB, so you can have that much sent by your application waiting to go
>>> > onto
>>> > the wire.  In total, this makes 8KB of buffering, but you only have
>>> > enough
>>> > pbufs to hold 4KB (16 * 256).  I think this is why you're running out.
>>> >
>>> > Kieran
>>> > _______________________________________________
>>> > lwip-users mailing list
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>>> > https://lists.nongnu.org/mailman/listinfo/lwip-users
>>> >
>>> >
>>>
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