TCP_INFO_v0 structure (mstcpip.h)

Contains the Transmission Control Protocol (TCP) statistics that were collected for a socket.

Syntax

typedef struct _TCP_INFO_v0 {
 TCPSTATE State;
 ULONG Mss;
 ULONG64 ConnectionTimeMs;
 BOOLEAN TimestampsEnabled;
 ULONG RttUs;
 ULONG MinRttUs;
 ULONG BytesInFlight;
 ULONG Cwnd;
 ULONG SndWnd;
 ULONG RcvWnd;
 ULONG RcvBuf;
 ULONG64 BytesOut;
 ULONG64 BytesIn;
 ULONG BytesReordered;
 ULONG BytesRetrans;
 ULONG FastRetrans;
 ULONG DupAcksIn;
 ULONG TimeoutEpisodes;
 UCHAR SynRetrans;
} TCP_INFO_v0, *PTCP_INFO_v0;

Members

State

A value from the TCPSTATE enumeration that indicates the state of the TCP connection.

Mss

The current maximum segment size (MSS) for the connection, in bytes.

ConnectionTimeMs

The lifetime of the connection, in milliseconds.

TimestampsEnabled

TRUE if TCP time stamps are turned on for the connection; otherwise FALSE.

RttUs

The current estimated round-trip time for the connection, in microseconds.

MinRttUs

The minimum sampled round trip time, in microseconds.

BytesInFlight

The current number of sent bytes that are unacknowledged.

Cwnd

The size of the current congestion window, in bytes.

SndWnd

The size of the send window (SND.WND in RFC 793), in bytes.

RcvWnd

The size of the receive window (RCV.WND in RFC 793), in bytes.

RcvBuf

The size of the current receive buffer, in bytes. The size of the receive buffer changes dynamically when autotuning is turned on for the receive window.

BytesOut

The total number of bytes sent.

BytesIn

The total number of bytes received.

BytesReordered

The total number of bytes reordered.

BytesRetrans

The total number of bytes retransmitted.

FastRetrans

The number of calls of the Fast Retransmit algorithm.

DupAcksIn

The total number of duplicate acknowledgments received.

TimeoutEpisodes

The total number of retransmission timeout episodes. Each episode can consist of multiple timeouts.

SynRetrans

The total number of retransmitted synchronize control flags (SYNs).

Remarks

To get an instance of this structure, call the WSAIoctl or LPWSPIoctl function with the SIO_TCP_INFO control code. Specify 0 for the lpvInBuffer field to retrieve the v0 version of this structure.

Requirements

See also

SIO_TCP_INFO

TCPSTATE