Data request

Direction

MTP 3 -> MTP 2

Description

Asks MTP 2 to transmit an MSU (message signal unit) on the specified data link.

The following table lists the message parameters:

Type

Field

Description

U8

Message Type

0x14

S16

Service Provider ID

MTP 2 reference number for the link on the TX board. Valid values are 0 through 15.

Variable

Data

The contents of the MSU to transmit. The first byte of data is typically the SIO (service information octet), followed by the routing label, and protocol dependent data. Layer 2 inserts the flags, sequence number, length indicator, and frame check sequence. The maximum length of the data field is 274 octets including the SIO. There is no field to specify the length of the data field. MTP 2 derives the length of the data from the message start and end offsets in the message.