TCP_ESTATS_FINE_RTT_ROD_v0 structure (tcpestats.h)

The TCP_ESTATS_FINE_RTT_ROD_v0 structure contains read-only dynamic information for extended TCP statistics on fine-grained round-trip time (RTT) estimation for a TCP connection.

Syntax

typedef struct _TCP_ESTATS_FINE_RTT_ROD_v0 {
  ULONG RttVar;
  ULONG MaxRtt;
  ULONG MinRtt;
  ULONG SumRtt;
} TCP_ESTATS_FINE_RTT_ROD_v0, *PTCP_ESTATS_FINE_RTT_ROD_v0;

Members

RttVar

Type: ULONG

The round trip time variation, in microseconds, used in receive window auto-tuning when the TCP extended statistics feature is enabled.

MaxRtt

Type: ULONG

The maximum sampled round trip time, in microseconds.

MinRtt

Type: ULONG

The minimum sampled round trip time, in microseconds.

SumRtt

Type: ULONG

A smoothed value round trip time, in microseconds, computed from all sampled round trip times. The smoothing is a weighted additive function that uses the RttVar member.

Remarks

The TCP_ESTATS_FINE_RTT_ROD_v0 structure is used as part of the TCP extended statistics feature available on Windows Vista and later.

The TCP_ESTATS_FINE_RTT_ROD_v0 is defined as version 0 of the structure for read-only dynamic information for extended TCP statistics on fine-grained round-trip time estimation for a TCP connection. This information is available after the connection has been established.

The TCP_ESTATS_FINE_RTT_ROD_v0 structure is retrieved by calls to the GetPerTcp6ConnectionEStats or GetPerTcpConnectionEStats functions when TcpConnectionEstatsFineRtt is passed in the EstatsType parameter. Extended TCP statistics need to be enabled to retrieve this structure.

The TCP retransmission timer is discussed in detail in the IETF RFC 2988 on Computing TCP's Retransmission Timer For more information, see http://www.ietf.org/rfc/rfc2988.txt.

The members of this structure are not defined in the IETF RFC on the TCP Extended Statistics MIB. However, there are members in the TCP_ESTATS_PATH_ROD_v0 structure that provide similar time measurements in milliseconds. For more information, see the TCP_ESTATS_PATH_ROD_v0 structure and http://www.ietf.org/rfc/rfc4898.txt.

Requirements

See also

GetPerTcp6ConnectionEStats

GetPerTcpConnectionEStats

TCP_ESTATS_PATH_ROD_v0

TCP_ESTATS_TYPE