Windows 2000 ?? Windows Server 2003 TCP ???????? ?? ?????

?? ???? ????? ???? ?? ?? Microsoft Windows 2000 ?? Microsoft Windows Server 2003 ??? ?????????? TCP ?????????:

• TCP ????? ?? ????
• ?? ??????? TCP ??????
• Windows ???????? - RFC 1323
• ??????????? - RFC 1323
• Wrapped ??????? ??????? (PAWS) ?? ??????? ???????
• ????? Acknowledgments (SACKS) - RFC 2018
• TCP Retransmission ??????? ?? ??? Retransmit

????????? ??? ???????????? ?? ????? TCP ???????? ????????? ???? ?? ???? ???

???????????? ???, ????, ?? ????? ?? ????????? ?? ??????? ???? ?? ??? ????? ????? ??? ???? ???????, ??? ?? ????????? ?? ??? ??? ?? ??????? ???? ??? ?? ????? ???????? ??????? ?? ???? ???.. ?????, ????????? ???? ?? ?? ?? ????? ?? ??????????? ???? ???? ???.. ?????? ??????? ?? ???, ????????? ?? ??????? ???? ?? ???? ???? ??? ?? ???.. ???, ??? ??? ?????? ??????? ???? ?? ?? ?? ????????? ?? ???????????? ?? ???? ???.. ????????? ?? ??? ?? ???? ?? ???????????? ???? ?? ????? ?? ???? ??? ???? ??????? ?? ???, Microsoft ?????? ??? ??? ???? ????? ?? ??? ????? ???? ?????? ????? ????::

TCP ????? ?? ????

TCP ??????? ????? ?? ???? ?? ?? ?????? ???? (??????) ??? ?? ??????? ???? ?? ????? ?????? ?? ???? ???? ?????? ????? ?? acknowledgment ?? ????? ???????????? ????? ?? ?????? ???? ?? ??? ????????? ???? ?????, ???? ???? ?? ???? ?? ?????? ??? ???? ???? Windows TCP/IP ????? self-tune ??????? ???????? ??? ????? ?? ??? ??????? ???? ??? ??, ?? ????? ????????? ?? ??? ??????? ????? ???? ?? ????? ???? ???

?? ????? ???? ?? ???? ???? ?????-coded ??????? ????? ?? ???? ??????? ????; TCP ??? ?? ?????? ???? (MSS), ?? ??????? ????? ?? ????? ???? ?? ?? ?? ?????? ?? ??? ???????? ???? ??? ??????? ????? ???? TCP ????? ???? ?????? ???? ????? ?? ????? utilized receive ????? MSS ?? ???? ?? ?? ???? ?? ??? ???????? ?????? ???

Receive ????? ?? ???? ????????? ????? ????? ?? ???? ??? ??:

1. ???? ?????? ????? ???? ?? ??? ???? ??? ???? ??????? ?????? advertises 16 K (16384 ??????) ?? ??? receive ????? ?? ???? ???
2. ??????? ??????? ??, ?? receive ????? ?? ???? ?? ???? MSS ?? ??? ?? ?????? ???? ?? ????
3. ????? ?? ???? 4 ??? MSS, 64 K ?? ?????? ???? ?? ??? ?? ??? ???????? ?? ?? ?? ?? ????? ?????? (RFC 1323) ???????? ?? ????? ???? ???? ???

???:"Windows ????????" ??? ??????

?????? ???????, ?? ??? ????? ?? ???? ????? ??????? ??? ?? ??? ???? ?? 17,520 ?????? (16 K ???????? 1460-???? ?? ???? ?? ?????) ?? ???? ????? ?? ???? ?? ????????? TCP head ??????, ???? ?? ????? Acknowledgments (SACKS) ?? Timestamps ?? ?????? ???? ?? ?? ???? ???????? ?? ??? ??? ??????? ??????? ???? ?? ??? ?? ?? ???? ??? ?? ?? ?????? TCP ????? ??? ???? ?????? ?????? ?? ???? 20, ?? ??? ?? ?????? ???? ?? ??? ?? ??????

Windows NT ?? ????? ????????? ??? ??? ?????? ??????? ?? ??? ????? ?? ???? ?? 8,760 ?????? ?? ?? 1460-???? ????

??? ??????? ??? ?? ??? receive ????? ?? ???? ??? ????, ???? ?? ??? TcpWindowSize ??? Windows ?? ???? ??????? ?? ??? ??????? ????????? ??????? ??? ??????? ??? ???? ?? ???, ????? ????? ?? ???? ????::

1. ????? ????,???????????? ????,???????????:regedit?? ????-????? ????, ?? ???? ???OK.
2. Windows ?? ???? ??????? ?? ??? ??????? ????????? ??????? ?? ??????? ????:
   • Windows 2000 ?? ??? ????? ??????? ?? ??????? ????:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters\Interfaces
   • Windows Server 2003 ?? ??? ????? ??????? ?? ??????? ????:
     HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters
3. ????? ?????????????? ??,????? ????-????? ????, ?? ???? ???DWORD ???.
4. ??????:TcpWindowSize???????? ???????? ???, ?? thne Enter ?????
5. ????? ????,??????? ????????? ?????????????? ??..
6. ?????? ????? ?? ???? ??? ???????? ????????? ????
   
   ???:. ????? ?? ???? ?? ??? ????? ?????? ?? 0-0x3FFFC000 Hexadecimal.

?? ??? ??????? ??? ??? ????? ???? ??? ?? ?? TcpWindowSize ??? ?? ?????? ???, ?? ??? discussed ??????? ????? ?? ???? ?????????? ??????? ???? ???

???:TcpWindowSize ?? globally ??? ??????? ?? ??? ????? ?? ???? ??? ???? ?? ??? ???????? ????? ????? ?? ???? ???

?? ??????? TCP ??????

?????? ??? TCP ?????? ??????? ?????? ??? ???? negotiating ?? ??? ????? ??? ?? ??? Windows, ??? TCP ?????? ??? ?? ?? ??? ????? ????? ????????, ??? ??????, ????? ACK.

????? ?????? ?? TCP ?????? ???:

1. ???? ??? octet TCP ??????, ??? ?? ???? ?????? ?? ????? ?????? ?? ????? ???? ?? ??? ????? ???? ???? ???
2. ???? ?? ?? ???? octet TCP ??????, ??? ?? ?? ?????? ??????, ?? ?????? ????? ?? ?????? octets ?? ?? ?????? ?? ????? ??? ?????

????? ???? ???????? TCP ?????? ??????, ?????, ???, ?? ????? ?????? ???

Windows scaling

For more efficient use of high bandwidth networks, a larger TCP window size may be used. The TCP window size field controls the flow of data and is limited to 2 bytes, or a window size of 65,535 bytes.

Since the size field cannot be expanded, a scaling factor is used. TCP window scale is an option used to increase the maximum window size from 65,535 bytes to 1 Gigabyte.

The window scale option is used only during the TCP 3-way handshake. The window scale value represents the number of bits to left-shift the 16-bit window size field. The window scale value can be set from 0 (no shift) to 14.

To calculate the true window size, multiply the window size by 2^S where S is the scale value.The following Network Monitor trace shows how the window scale option is used:It's important to note that the window size used in the actual 3-way handshake is NOT the window size that is scaled. This is per RFC 1323 section 2.2, "The Window field in a SYN (for example, a [SYN] or [SYN,ACK]) segment itself is never scaled."

This means that the first data packet sent after the 3-way handshake is the actual window size. If there is a scaling factor, the initial window size of 65,535 bytes is always used. The window size is then multiplied by the scaling factor identified in the 3-way handshake. The table below represents the scaling factor boundaries for various window sizes.


?????? ?? ???::

??? ????? ???? ??? ????????? ?? 269000000 (269 M) ?? ??? ??? ??? ???? ??? ?? ?????, 3 ?? ??? handshake ?? ????? ???????? ?????? ?? 13, 12 ?? ??? ???????? ?????? ???? ?? ?????? ???? ??????? ??? ????? ?? ???? ?? 268,431,360 ?????? (268 M)?

?? ?????? ??? ????????? ????? ?? ???? ??????????? ??????? ???? ?? ?? ????:????? ?? ???? ?? ??? ??? ????????? ??? ????? ??, ?? ???? ???? ??????? ??? ?? ???? ??, ?? Windows ?? ????? ?? ???? accommodates ????? ??? ?? ????? ???? ?? ?????? ???? ???

???????? ????? ?? ??????????? ?? ????????? ???? ?? ??? Tcp1323Opts ??? ????? ????????? ????? ??? ????? ?? ???? ??:

1. ????? ????? ????? ?????????????? ????,?????, ?? ??? ???? ????regedit????????? ?????? ?? ??????? ?????
2. ????????? ?????? ???, ????? ???????????? ????? ????,????? ????-????? ????, ?? ???? ???DWORD ???.
3. ???????? ???????? ???,Tcp1323Opts??? ?????ENTER, ?? ???? ??? ???????????? ??,??????? ????.???:????? ?????? 0,1,2 ?? 3 ???? ??:

?? ????????? ????????? RFC 1323 timestamps ?? ????? ?????? ???????? ????????? ???? ??? Timestamps ?? ???????? ??? ?? ?????? ????? ????????, ????? ???? ????? ?? ??? manipulated ?? ???? ???? 0 ???????? ????? ???????? ???, ?? 1 ???????? timestamps ??? ???

Timestamps

????, TCP/IP ????? ????? ?? ????? (RTT) ????? ????? ??? ?? ???? ???? ?? ??? ???? ??? ??? ???? ?? ????? ?? ????? ??? ???? ????? (retransmit ?????) ????? ???? ??? ??, ?? ?? ?? acknowledgment ??????? ??? ?? ?? ?? ??? ??? ???? ??? ??? ?????? ?? ???, ??? ????? ?? ???? ?? ?????? ??????? ?? 64,240 ?????? (44 ????? ?????) ???? ??? ??, ???????? 44 ????? ??? ?? ???? ?? ?? ?? ????? ?? ??? ????? ????? ??? ?? ??? ?? ??????? ????? ???? ????? ?? ?????? ???? 65,535 ?????? ??, ?? ??? ?? sampling ?? ?? ????????? ????? ????????, ?? ???? ????? ?? ?????? ???? ?? 1 ???????? ?? ????? ???? ???, ?? RTT sampling ?? ???????? ???? ???

TCP ??????????? ?????? ?? ???? ??? ?? RTT ????, PAWS ???, ???? ???????? ???? ?? ??? ??? (???? ?? ACK) ?????? ????? ??????? deemed ?? ????? ?? ??? ??? ???? ?? ???? ?? on ???? ?? ???? ?? ????? ??, RTT ?? ???? ?? ?????? ??????? ???? ????? ?? ???? ?? ???? RTT retransmission ?????? ?? ???? ???? ?? ??? ????? ???? ???? ??? ????? RTT ?? retransmission timeouts ?? optimum ?????? ?? ??? ?????? ???

????? TCP ??? ??????? ?? TCP ???? ??? ????? ???? ???? ??, ?? ???? ?? ???????? ?? ?????? TCP ??? ??? handshake (SYN ?????) ?? ???? ???? ????? ???? ???? ?? ?? ???? ?? ????? TCP ?????? ?? ????? ?? ?? ???? ????

TCP Timestamps ?????? (TSopt):


??????????? ?????? ????? ???? ?? ???? ??? ?? ??????? ?????? ????? TCP ?????? ????? ?? ??????? ???? ?? ?????? ???? ????? ?? ?? ??? ???:

Wrapped ??????? ??????? (PAWS) ?? ??????? ???????

TCP ??????? ?????? ????? ?? ????? ?? 32 ?????, ?? ???? ?????? ?????? ?? ?????? ????? ???? ??? ???? ?????? ????????? ?? ?? ??? ???? ?? ??????????, ?? ??? ??? ????? traverses ??????? ?? ???? ??????? ?????? ?? ?????? ?? ??? ??????? ??? ??? ??? 1 Giga-???? ????? ????? (Gbps) ??????? ?? ???? ??? ??? ??, ??????? ?????? ??? 34 ????? ?? ??? ???? ??? ??? ????? ????? ??, ??? ???? ?????? ?? ??? ???? ????? ????? ????? ??????? ???? ????????? ??????? ?????? ?? ???? ??? confusion ?? ????, ?? ??? TCP ??????????? ????????? ??????? ?????? ?? ??? ??? ????? ???? ???? ??? ????? ?? ??????? ?? progressing ??? stamps ??? ???? ?????? ????? ???? ?????? ??? ??????? ?? ?? ?? ??? ?? ???

????? Acknowledgements (SACKs)

Windows ????? Acknowledgement ?? SACK ?? ??? ??? ????? ???????? ?????? ?? ??? ?????? introduces ??? SACK ??? TCP ????? ???? ?? ????? ???? ???? ??????? ?? ??? ????? ??? ?? ?????????? ??? SACK, ???? ?? ???? ??? ???????????? ??? ???? acknowledge ??????? ?? ?? ?? ?? ?????? ???? ?????? ?? ?????? ??????? ??????, ?? "?? ???? ??????" receive ?????? SACK ????? ??, ?? ??? ?????? receive ????? ?? ???? ?????? acknowledge ???? ?? ??? ACK ???? ?? ????? ???? ?? ??? ???? ???? ??, ????? ?? ?? ???? ??? ?? acknowledge ???? ????? ?? ??????? ??? ?? ???? ?? ???-??? ??? SACK TCP ????? ??? ?????? ?? ??? ??? ???? ????? ?? ?? ????? ???? ???

SACK ?? ?????? ?? TCP ?????? ?? ????? ???? ???

TCP Sack-Permitted ?????? ?? ????? ???? ?? SYN ????? ??? (??? TCP ??????? establishment) ????? ???? ??? ?? ?? ????? ACK. ???? ?? ???? ??? ?? ???

????? TCP ??????, TCP Sack ?????? ??? ???? ?? ?? ?? ???? ????? ???? ?? ??? acknowledgment ??? ???? ??? ??????? ?????? ?? ????? ?? ??????? ??? ?? ?? ??? ?? ???? ?? ??? ??? ?????? ???? ???? ?? ??? ?? ???? ?? ???? ?? ???? ?????? ?? ???? ???

4 ?????? ?? TCP Sack-Permitted ?????? ??, ?????? 5 ?? TCP Sack ?????? ??? ????? ??? ?????? ??? ????? ?? ?? TCP ?????? ???

TCP Sack ?? ?????? ??:


TCP SACK ??????:


????? ?? SACK ????? (???????), ?? ??? ????? ?? ????? ?? ???????? ?? ???? ?? ??, ?? ?? ???? ??? ??????? ?????? ???? ?????? ???-?? ???? ??????? ???, ?? ???? ?? "holes" ???? ??? ??? ?????? ?? ??? ???? ?? ?? ???? ??? ??????? ??????????? ???? ??? ?? ???? retransmission ???? ???? ???????? ??? ?? retransmit ?? ?? ???? ???? SACK ?? SackOpts ????????? ???????? ?????? ????????? ???

????? acknowledgements ?? ????? ?? ????????? ???? ?? ??? ????? ????????? ????? ??? SackOpts ??? ??????? ???? ?? ???? ??:

1. ????? ????? ????? ?????????????? ????,?????, ?? ??? ???? ????regedit????????? ?????? ?? ??????? ?????
2. ?????? ????? ?? ????????? ?????? ??? ??? ????? ?? ????? ????, ?? ???? ?????????? ????????? ?????????????? ??..
3. ?????? ??? ???????? ????????? ????

???:: 0 ?? 1 ?????? ??? ????? ??, ??????? ??? 1 ??? ?? ???????? ?????????? ?? ???? ?? ????? ACK (SACK - RFC 2018) ?????? ????? ???? ??? ???

????? ??????? ?????? ????? illustrates ???? ????? ??????? ?????? 54857341 ?? ??? ???? ?? ???? ?? ??????? ?????? 54858789 54861685 ?? acknowledging ??? ??? ???? ?? 54857341 ?? 54858788 ???? ?? ????

TCP retransmission ??????? ?? ??? retransmit

TCP Retransmission

??????? retransmission ??????? ?? ???????, ?? ??? ??? TCP ??????? ?? retransmission ????? ?? ???????? ???????? ??? ?? handed ???? ?? ??? ??????? ????????? (IP)? ??? ??? acknowledgment ??????? ??? ???? ??? ?? ??? ??? ???? ?? ??? ????? ?? ??????? ?????? ???? ??, ???? ?? ???? ??? retransmitted ??? ???

(RTO) retransmission ???????? ?? ???????? ?????? RFC 793 ??? ???? ?????? Smoothed ??? ????? ??? (SRTT) ?????? ?? ????? ??????? ?? ????????? ?? ??? ???? ?? ???? ????? ?? ??? ?? ??? ?? ??? ???????? retransmission ?? ?? ??? ?? ??? doubled ?? ??? ?? ?????????? ?? ????? ?? ??? ??, ?? TCP tunes ????? ?? ??????? ?? ??????? ????? ?? ????

??? Retransmit

TCP retransmits ???? ?? ??? ???????????? ?? ??? retransmission ????? ??????? ?????? ???? ?? ????? ???? ??????? ?? ?? ???? ?? ???? ??? ?????? ??? retransmit ?? ??? ??? ???? ???? ??? ?? ?????? ?? ?????? ???? ???? ??? ???????????? retransmits ??????? ???????? ?? ?? ??? ???? ??????? ?????? ?? ??? ???? ??????? ????, ?? ???? ??? ?? ???? ?? ?? ??? ???? ????? ?? ?? ?? ??? ????? ?? ????? ?? ?????? ?? ????? ???? ?? ???, ?????? ????? ?? ?? ACK, ?? ACK ?????? ??? ???? ?? ??? ??????? ?????? ???????? ??? ???????? ???????? TCP ??? ?? ?? ??? ?? ??? ??? ???? ?? ??? ?? ???? ?????? ?????? ACKs ?? ?? ??????? acknowledging ???? ??????? ?????? ?? ?? ??????? ???? ?? ??? ??????? ???? ??, ?? ?? ???? ?? ?? ????? ?? ?? ??? ??? ??? ?? ?? ?? ??? ?????? ??? ?????? ?? ????????, ?? ???? retransmission ????? ?? ??????? ?????? ???? ?? ??? ????????? ?? ??? ?? ?? ????? ??? ?? ????? ??????? ?? ???????????? ?? ??????????? ?? ??????? ?? ?? ????? ????? ????? ???? ????? ????

???????? ??? ??, Windows resends ??? ??? ??? ??? ????? ???? ?? ?? ??????? ??????, (?? ACK ?? 2 ?????????) ?? ??? ??? ACKs ?? ?? ??????? ?????? lags ??????? ??? ?? TcpMaxDupAcks ????????? ???????? ?? ??? controllable ???

???? ??? ??????? ???? ?? ??? ?????? ACKs ?? ?????? retransmits ?? ???????? ???? ?? ??? ????? ????????? ????? ??? TcpMaxDupAcks ??? ??????? ???? ?? ???? ??:

1. ????? ????? ????? ?????????????? ????,?????, ?? ??? ???? ????regedit????????? ?????? ?? ??????? ?????
2. ?????? ????? ?? ????????? ?????? ??? ??? ????? ?? ????? ????, ?? ???? ?????????? ????????? ?????????????? ??..
3. ?????? ??? ???????? ????????? ????

???:: ????? ?????? ?? 1-3 ??, ??????? ??? 2 ???

?? ???????? ?? ?????? ?? ???? ?? ???? ?? ?? ?? ??????? ?????? ?? ??? "retransmit ??????" ??? ??? transit ????? ???? ????? ???? ??? ?? ?? ???: ????? ?? ??? ?????? ?? ?? ???? ????????? ACKs ?? ?????? ????????? ???? ???