MTP2

Error Control

Checks the error in a received frame based on 16 bits CRC. Re-transmits lost message or error message.

Sequencing

Maintains the sequencing of messages between directly connected nodes. Forward and backward sequencing numbers are maintained for sequence and re-transmissions.

Link Alignment

Is link alignment based on the request from MTP3.

Flow control

If the receiver is slow, sending mtp2 gives an indication to its user for congestion.

Link Status

Link status is given to the user , the status may be, in service , out of service or congestion.