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TCP_ESTATS_SYN_OPTS_ROS_v0 structure (tcpestats.h)

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The TCP_ESTATS_SYN_OPTS_ROS_v0 structure contains read-only static information for extended TCP statistics on SYN exchange for a TCP connection.

Syntax

typedef struct _TCP_ESTATS_SYN_OPTS_ROS_v0 {
  BOOLEAN ActiveOpen;
  ULONG   MssRcvd;
  ULONG   MssSent;
} TCP_ESTATS_SYN_OPTS_ROS_v0, *PTCP_ESTATS_SYN_OPTS_ROS_v0;

Members

ActiveOpen

Type: BOOLEAN

A value that indicates if the TCP connection was an active open.

If the local connection traversed the SYN-SENT state, then this member is set to TRUE. Otherwise, this member is set to FALSE.

MssRcvd

Type: ULONG

The value received in an Maximum Segment Size (MSS) option during the SYN exchange, or zero if no MSS option was received.

This value is the maximum data in a single TCP datagram that the remote host can receive.

MssSent

Type: ULONG

The value sent in an MSS option during the SYN exchange, or zero if no MSS option was sent.

Remarks

The TCP_ESTATS_SYN_OPTS_ROS_v0 structure is used as part of the TCP extended statistics feature available on Windows Vista and later.

The TCP_ESTATS_SYN_OPTS_ROS_v0 is defined as version 0 of the structure for read-only static information on SYN exchange for a TCP connection. The TCP protocol does not permit the members of this structure to change after the SYN exchange. This information is available after the SYN exchange has completed.

The TCP_ESTATS_SYN_OPTS_ROS_v0 structure is retrieved by calls to the GetPerTcp6ConnectionEStats or GetPerTcpConnectionEStats functions when TcpConnectionEstatsSynOpts is passed in the EstatsType parameter. Extended TCP statistics do not need to be enabled to retrieve this structure.

The MSS in the MssRcvd and MssSent members is the maximum data in a single TCP datagram. The MSS can be a very large value.

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_SYN_OPTS_ROS_v0 structure to the entries defined in RFC 4898 for extended TCP statistics:

Term Description
ActiveOpen tcpEStatsStackActiveOpen
MssRcvd tcpEStatsStackMSSRcvd
MssSent tcpEStatsStackMSSSent

Requirements

Requirement Value
Minimum supported client Windows Vista [desktop apps only]
Minimum supported server Windows Server 2008 [desktop apps only]
Header tcpestats.h

See also

GetPerTcp6ConnectionEStats

GetPerTcpConnectionEStats

TCP_ESTATS_TYPE