Hi,
first, I want to say that I'm new to this lwip world. I'm trying to make a
Ethernet speed test using the EVK1100 board from ATMEL (AVR32). The
communication will be between the board and a PC using 2 ports, one
dedicated to bidir requests/responses between the board and the host, the
other dedicated to maximum speed data sending from the board to the host. I
would like to be able to send packets of 32768 bytes.
I searched a lot on the suject, especially on how to configure the
lwipopts.h file. I found some usefull information, but I must say that I'm
raelly not confortable will all those options.
Presently, for some reason, I can't send packets bigger than 1024 bytes.
Even if I write this:
writeRet = netconn_write(pNewConnection, g_pSDRAM, 2048, NETCONN_COPY);
what I get on the PC is 1024-byte packets. Tracing in the code, I found that
my connection is correctly configured ("pcb->mss" is 2048) but for some
reason, "pcb->mss" becomes 1460 somewhere (found by tracing in tcp_out.c).
Below, I copied some of the parameters I have in the lwipopts.h file.
Thanks a lot, because I really don't know what to check at this point!!
Downy
/* MEM_ALIGNMENT: should be set to the alignment of the CPU for which
lwIP is compiled. 4 byte alignment -> define MEM_ALIGNMENT to 4, 2
byte alignment -> define MEM_ALIGNMENT to 2. */
#define MEM_ALIGNMENT 4
/* MEM_SIZE: the size of the heap memory. If the application will send
a lot of data that needs to be copied, this should be set high. */
#define MEM_SIZE 4 * 1024
/* ---------- Pbuf options ---------- */
/* PBUF_POOL_SIZE: the number of buffers in the pbuf pool. */
#define PBUF_POOL_SIZE 10
/* PBUF_POOL_BUFSIZE: the size of each pbuf in the pbuf pool. */
#define PBUF_POOL_BUFSIZE 512
/* PBUF_LINK_HLEN: the number of bytes that should be allocated for a
link level header. Defaults to 14 for Ethernet. */
#define PBUF_LINK_HLEN 14
/* ---------- TCP options ---------- */
#define LWIP_TCP 1
#define TCP_TTL 255
#define TCP_WND 4096
/* Controls if TCP should queue segments that arrive out of
order. Define to 0 if your device is low on memory. */
#define TCP_QUEUE_OOSEQ 1
/* TCP Maximum segment size. */
#define TCP_MSS 2048
/* TCP sender buffer space (bytes). */
#define TCP_SND_BUF TCP_MSS * 16
/* TCP sender buffer space (pbufs). This must be at least = 2 *
TCP_SND_BUF/TCP_MSS for things to work. */
#define TCP_SND_QUEUELEN 6 * TCP_SND_BUF/TCP_MSS
/* Maximum number of retransmissions of data segments. */
#define TCP_MAXRTX 6
/* Maximum number of retransmissions of SYN segments. */
#define TCP_SYNMAXRTX 6
--
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