T_INFO_ACK(D7tpi)

T_INFO_ACK -- Protocol Information Acknowledgment

Synopsis

This message consists of a M_PCPROTO message block formatted as follows:

   struct T_info_ack {
   	long PRIM_type;		/* always T_INFO_ACK */
   	long TSDU_size;		/* max TSDU size */
   	long ETSDU_size;		/* max ETSDU size */
   	long CDATA_size;		/* Connect data size */
   	long DDATA_size;		/* Discon data size */
   	long ADDR_size;		/* TSAP size */
   	long OPT_size;		/* options size */
   	long TIDU_size;		/* TIDU size */
   	long SERV_type;		/* service type */
   	long CURRENT_state;	/* current state */
   	long PROVIDER_flag;	/* provider flags */
   }

Description

This primitive indicates to the transport user any relevant protocol-dependent parameters. It should be initiated in response to the T_INFO_REQ primitive described above. The format of this message is one M_PCPROTO message block.

Parameters

The fields of this message have the following meanings:

PRIM_type

This indicates the primitive type.

TSDU_size

A value greater than zero specifies the maximum size of a transport service data unit (TSDU); a value of zero specifies that the transport provider does not support the concept of TSDU, although it does support the sending of a data stream with no logical boundaries preserved across a connection; a value of -1 specifies that there is no limit on the size of a TSDU; and a value of -2 specifies that the transfer of normal data is not supported by the transport provider.

ETSDU_size

A value greater than zero specifies the maximum size of an expedited transport service data unit (ETSDU); a value of zero specifies that the transport provider does not support the concept of ETSDU, although it does support the sending of an expedited data stream with no logical boundaries preserved across a connection; a value of -1 specifies that there is no limit on the size of an ETSDU; and a value of -2 specifies that the transfer of expedited data is not supported by the transport provider.

CDATA_size

A value greater than or equal to zero specifies the maximum amount of data that may be associated with connection establishment primitives; and a value of -2 specifies that the transport provider does not allow data to be sent with connection establishment primitives.

DDATA_size

A value greater than or equal to zero specifies the maximum amount of data that may be associated with the disconnect primitives; and a value of -2 specifies that the transport provider does not allow data to be sent with the disconnect primitives.

ADDR_size

A value greater than or equal to zero indicates the maximum size of a transport protocol address; and a value of -2 specifies that the transport provider does not provide user access to transport protocol addresses.

OPT_size

A value greater than or equal to zero indicates the maximum number of bytes of protocol-specific options supported by the provider; and a value of -2 specifies that the transport provider does not support user-settable options.

TIDU_size

This is the amount of user data that may be present in a single T_DATA_REQ or T_EXDATA_REQ primitive. This is the size of the transport protocol interface data unit, and should not exceed the tunable system limit, if non-zero, for the size of a STREAMS message.

SERV_type

This field specifies the service type supported by the transport provider, and is one of the following:

T_COTS: The provider service is connection oriented with no orderly release support.
T_COTS_ORD: The provider service is connection oriented with orderly release support.
T_CLTS: The provider service is a connectionless transport service.

CURRENT_state

This is the current state of the transport provider.

PROVIDER_flag

This field specifies additional properties specific to the transport provider and may alter the way the transport user communicates. The following flags may be set by the provider:

SENDZERO: This flag indicates that the transport provider supports the sending of zero-length TSDUs.
XPG4_1: This flag indicates that the transport provider supports XPG4 semantics.

Rules

The following rules apply when the type of service is T_CLTS:

The ETSDU_size, CDATA_size and DDATA_size fields should be -2.
The TSDU_size should equal the TIDU_size.

Modes

Both connection-mode and connectionless-mode.

Originator

Transport provider.

Notices

Hardware constraints

None

Applicability

N/A

Backward compatibility

UnixWare-specific TPI Message Formats

Forward compatibility

N/A