TCP_ESTATS_DATA_ROD_v0 structure (tcpestats.h)

The TCP_ESTATS_DATA_ROD_v0 structure contains read-only dynamic information for extended TCP statistics on data transfer for a TCP connection.

Syntax

typedef struct _TCP_ESTATS_DATA_ROD_v0 {
  ULONG64 DataBytesOut;
  ULONG64 DataSegsOut;
  ULONG64 DataBytesIn;
  ULONG64 DataSegsIn;
  ULONG64 SegsOut;
  ULONG64 SegsIn;
  ULONG   SoftErrors;
  ULONG   SoftErrorReason;
  ULONG   SndUna;
  ULONG   SndNxt;
  ULONG   SndMax;
  ULONG64 ThruBytesAcked;
  ULONG   RcvNxt;
  ULONG64 ThruBytesReceived;
} TCP_ESTATS_DATA_ROD_v0, *PTCP_ESTATS_DATA_ROD_v0;

Members

DataBytesOut

Type: ULONG64

The number of octets of data contained in transmitted segments, including retransmitted data. Note that this does not include TCP headers.

DataSegsOut

Type: ULONG64

The number of segments sent containing a positive length data segment.

DataBytesIn

Type: ULONG64

The number of octets contained in received data segments, including retransmitted data. Note that this does not include TCP headers.

DataSegsIn

Type: ULONG64

The number of segments received containing a positive length data segment.

SegsOut

Type: ULONG64

The total number of segments sent.

SegsIn

Type:

The total number of segments received.

SoftErrors

Type: ULONG

The number of segments that fail various consistency tests during TCP input processing. Soft errors might cause the segment to be discarded but some do not. Some of these soft errors cause the generation of a TCP acknowledgment, while others are silently discarded.

SoftErrorReason

Type: ULONG

A value that identifies which consistency test most recently failed during TCP input processing. This object is set every time the SoftErrors member is incremented.

SndUna

Type: ULONG

The value of the oldest unacknowledged sequence number. Note that this member is a TCP state variable.

SndNxt

Type: ULONG

The next sequence number to be sent. Note that this member is not monotonic (and thus not a counter), because TCP sometimes retransmits lost data by pulling the member back to the missing data.

SndMax

Type: ULONG

The farthest forward (right most or largest) sequence number to be sent. Note that this will be equal to the SndNxt member except when the SndNxt member is pulled back during recovery.

ThruBytesAcked

Type: ULONG64

The number of octets for which cumulative acknowledgments have been received. Note that this will be the sum of changes to the SndNxt member.

RcvNxt

Type: ULONG

The next sequence number to be received. Note that this member is not monotonic (and thus not a counter), because TCP sometimes retransmits lost data by pulling the member back to the missing data.

ThruBytesReceived

Type: ULONG64

The number of octets for which cumulative acknowledgments have been sent. Note that this will be the sum of changes to the RcvNxt member.

Remarks

The TCP_ESTATS_DATA_ROD_v0 structure is used as part of the TCP extended statistics feature available on Windows Vista and later.

The TCP_ESTATS_DATA_ROD_v0 is defined as version 0 of the structure for read-only dynamic information for extended TCP statistics on data transfer for a TCP connection. This information is available after the connection has been established.

The TCP_ESTATS_DATA_ROD_v0 structure is retrieved by calls to the GetPerTcp6ConnectionEStats or GetPerTcpConnectionEStats functions when TcpConnectionEstatsData is passed in the EstatsType parameter. Extended TCP statistics need to be enabled to retrieve this structure.

The members of this structure are defined in the IETF RFC on the TCP Extended Statistics MIB. For more information, see http://www.ietf.org/rfc/rfc4898.txt.

The following is the mapping of the members in the TCP_ESTATS_DATA_ROD_v0 structure to the entries defined in RFC 4898 for extended TCP statistics:

Requirements

See also

GetPerTcp6ConnectionEStats

GetPerTcpConnectionEStats

TCP_ESTATS_TYPE