★★★为何我的recv（）一次只能接1460字节以下？哪里需要设置？详细见内。

[baobao]

server想client发25000字节，可client一次只能接1460或更少,这样还要client经过多次组装才能使用（降低了速度）。
一次一定可以接更多，要不pch最大1460好了。

m_hSocket=socket(AF_INET, nType, 0)

.....

int nBytesReceived;
nBytesReceived = recv(m_hSocket, pch, nSize, 0);

[lakegogo]

因为TCP的缘故，限定了每个分组的大小为1460。

[hongyucn]

MTU (Maximum Transfer Unit) specifies the maximum transmission unit size of an interface. Each interface used by TCP/IP may have a different MTU value specified. The MTU is usually determined through negotiation with the lower driver, using that lower driver value. However, that value may be overridden.

Each media type has a maximum frame size that cannot be exceeded. The link layer is responsible for discovering this MTU and reporting it to the protocols above. NDIS drivers may be queried for the local MTU by the protocol stack. Knowledge of the MTU for an interface is used by upper layer protocols such as TCP, which optimizes packet sizes for each medium automatically.

If a network interface card (NIC) driver such as an ATM driver uses LAN emulation mode, it may report that it has an MTU higher than what is expected for that media type. For instance, it may emulate Ethernet but report an MTU of 9180 bytes. Windows NT accepts and uses the MTU size reported by the adapter even when it exceeds the normal MTU for a given media type.

Below is a list of Default MTU size for different media.



Network MTU(Bytes)
-----------------------------------
16 Mbit/Sec Token Ring 17914
4 Mbits/Sec Token Ring 4464
FDDI 4352
Ethernet 1500
IEEE 802.3/802.2 1492
X.25 576

[ksyou]

没办法，只能这样，up

[tcice]

TCPSegMentSize是发送接受时单个数据报的最大长度，系统默认为1460，收发缓冲大小为8192。

在SOCK_STREAM方式下，如果单次发送数据超过1460，系统将分成多个数据报传送，在对方接受到的将是一个数据流，应用程序需要增加断帧的判断。当然可以采用修改注册表的方式改变1460的大小，但MicrcoSoft认为1460是最佳效率的参数，不建议修改。

[jobine]

文档http://www.csdn.net/develop/Article/14/14641.shtm中有说明