What is MPS(maxium payload size) in IPSP

Question

what is MPS and what is the need of it L2CAP credit based channel..? 
 What is the difference between MPS and MTU..?

Petter Myhre · Accepted Answer

MPS is the maximum payload size that the L2CAP layer is capable of receiving. 
 MTU is the maximum SDU size that the L2CAP layer can receive. 
 IPSP specifies that the MTU size shall be 1280 octets or higher, and in our SoftDevice the MPS is 27 octets. 
 So if the L2CAP layer receives an SDU of 1280 octets it will fragment it into 27 octet sized pieces, and give each piece to the link layer which will transmit it. On the other side of the link layer will receive the pieces and give them to the L2CAP layer which will reassemble them into the 1280 octet SDU.