3.17 Connection request The format of the connection request parameter field is shown in Figure 18. 8 7 6 5 4 3 2 1 1 2 Local reference 3 4 5 Spare Signalling point code 6 Protocol class 7 Credit NOTE - Octets 6 and 7 may be omitted if protocol class requested is 2. Figure 18/Q.763 - Connection request parameter field The following codes are used in the subfields of the connection request parameter field: a) Local reference A code indicating the local reference allocated by the signalling connection control part to the end-to-end connection. b) Signalling point code A code identifying the signalling point at which the connection request originated. c) Protocol class A code identifying in pure binary representation, the protocol class requested for the end-to-end connection. d) Credit A code identifying in pure binary representation the window size requested for the end-to-end connection.