In 1991, Originally Bosch released CAN specification CAN 2.0 for passenger Vehicles which explains 11- bit identifier frame architecture but later on it divided into CAN 2.0(A) which is named as standard CAN be used in passenger cars dealing with 11-bit Identifier while other is CAN2.0(B) which is known as extended CAN be used in heavy vehicles like Buses and Trucks it deals with 29-bit Identifier. So the basic difference in both standard at message Identifier field.
CAN2.0A for Standard Frame Format for Passenger Vehicles
CAN2.0B for Extended Frame Format for Heavy Vehicles
The standard frame format is specified in can Specification CAN2.0(A) by Robert Bosch. See below table for frame fields,sub-fields and its role in CAN Frame-
Note : Identifier available in standard CAN is 2048(2^11) but 2032 is available due to some implementation reason.
The extended Frame of CAN is almost similar to the standard frame except for its arbitration field. See below table for frame fields,sub-fields and its role in CAN Frame –
So as you can see Arbitration field in the extended frame format only differ from the standard CAN means extended CAN architecture designed in such a way that standard and extended CAN coexist on the same network.
Note: Available Identifier in Extended CAN is about 500 million (2^29).