Packet format for a distributed system

A method is provided for transmitting a packet including information describing a bus transaction to be executed at a remote device. A bus transaction is detected on a first bus and a network packet is generated for transmission over a network. The network packet includes an opcode describing the type of bus transaction. One or more control signals of the bus transaction map directly to one or more bits of the opcode to simplify decoding or converting of the bus transaction to the opcode. The packet is transmitted to a remote device and the bus transaction is then replayed at a second bus. In addition, the packet includes a data field having a size that is a multiple of a cache line size. The packet includes separate CRCs for the data and header. The packet also includes a transaction ID to support split transactions over the network. Also, fields in the packet header are provided in a particular order to improve switching efficiency.