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MIB_TCPSTATS_LH structure (tcpmib.h)

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The MIB_TCPSTATS structure contains statistics for the TCP protocol running on the local computer.

Syntax

typedef struct _MIB_TCPSTATS_LH {
  union {
    DWORD             dwRtoAlgorithm;
    TCP_RTO_ALGORITHM RtoAlgorithm;
  };
  DWORD dwRtoMin;
  DWORD dwRtoMax;
  DWORD dwMaxConn;
  DWORD dwActiveOpens;
  DWORD dwPassiveOpens;
  DWORD dwAttemptFails;
  DWORD dwEstabResets;
  DWORD dwCurrEstab;
  DWORD dwInSegs;
  DWORD dwOutSegs;
  DWORD dwRetransSegs;
  DWORD dwInErrs;
  DWORD dwOutRsts;
  DWORD dwNumConns;
} MIB_TCPSTATS_LH, *PMIB_TCPSTATS_LH;

Members

dwRtoAlgorithm

Type: DWORD

The retransmission time-out (RTO) algorithm in use. This member can be one of the following values:

Value Meaning
MIB_TCP_RTO_OTHER
1
 Other
MIB_TCP_RTO_CONSTANT
2
 Constant Time-out
MIB_TCP_RTO_RSRE
3
 MIL-STD-1778 Appendix B
MIB_TCP_RTO_VANJ
4
 Van Jacobson's Algorithm

RtoAlgorithm

dwRtoMin

Type: DWORD

The minimum RTO value in milliseconds.

dwRtoMax

Type: DWORD

The maximum RTO value in milliseconds.

dwMaxConn

Type: DWORD

The maximum number of connections. If this member is -1, the maximum number of connections is variable.

dwActiveOpens

Type: DWORD

The number of active opens. In an active open, the client is initiating a connection with the server.

dwPassiveOpens

Type: DWORD

The number of passive opens. In a passive open, the server is listening for a connection request from a client.

dwAttemptFails

Type: DWORD

The number of failed connection attempts.

dwEstabResets

Type: DWORD

The number of established connections that were reset.

dwCurrEstab

Type: DWORD

The number of currently established connections.

dwInSegs

Type: DWORD

The number of segments received.

dwOutSegs

Type: DWORD

The number of segments transmitted. This number does not include retransmitted segments.

dwRetransSegs

Type: DWORD

The number of segments retransmitted.

dwInErrs

Type: DWORD

The number of errors received.

dwOutRsts

Type: DWORD

The number of segments transmitted with the reset flag set.

dwNumConns

Type: DWORD

The number of connections that are currently present in the system. This total number includes connections in all states except listening connections.

Remarks

The GetTcpStatistics function returns a pointer to a MIB_TCPSTATS structure.

The MIB_TCPSTATS structure changed slightly on Windows Vista and later. On Windows Vista and later, the dwRtoAlgorithm member is replaced by a union that contains the following members.

Member Description
DWORD dwRtoAlgorithm The retransmission time-out (RTO) algorithm in use.
TCP_RTO_ALGORITHM RtoAlgorithm The retransmission time-out (RTO) algorithm in use. This member can be one of the values from the TCP_RTO_ALGORITHM enumeration type defined in the Tcpmib.h header file. The possible values are the same as those defined for the dwRtoAlgorithm member.
 

In the Windows SDK, the version of the structure for use on Windows Vista and later is defined as MIB_TCPSTATS_LH. In the Windows SDK, the version of this structure to be used on earlier systems including Windows 2000 and later is defined as MIB_TCPSTATS_W2K. When compiling an application if the target platform is Windows Vista and later (NTDDI_VERSION >= NTDDI_LONGHORN, _WIN32_WINNT >= 0x0600, or WINVER >= 0x0600), the MIB_TCPSTATS_LH structure is typedefed to the MIB_TCPSTATS structure. When compiling an application if the target platform is not Windows Vista and later, the MIB_TCPSTATS_W2K structure is typedefed to the MIB_TCPSTATS structure.

On the Microsoft Windows Software Development Kit (SDK) released for Windows Vista and later, the organization of header files has changed. This structure is defined in the Tcpmib.h header file, not in the Iprtrmib.h header file. Note that the Tcpmib.h header file is automatically included in Iprtrmib.h, which is automatically included in the Iphlpapi.h header file. The Tcpmib.h and Iprtrmib.h header files should never be used directly.

Requirements

Requirement Value
Minimum supported client Windows 2000 Professional [desktop apps only]
Minimum supported server Windows 2000 Server [desktop apps only]
Header tcpmib.h (include Iphlpapi.h)

See also

GetTcpStatistics

GetUdpStatistics

MIB_UDPSTATS