With the five key reasons for using CAN in mind, let's now summarize the main features of CAN that underlie it's growing application popularity. CAN has a multiple-master hierarchy. This arrangement gives good design flexibility and allows us to build intelligent and redundant systems. CAN operates at transfer rates up to 1 Megabit/second (1Mbps) in CAN 2.0B. This speed provides sufficient data-communication bandwidth for many real-time control systems. The CAN protocol allows each CAN data frame to carry up to eight bytes of user data per message, thus accomodating a wide span of signaling requirements. If necessary, more data can be transmitted per message using a higher-layer segmentation protocol. Each node on a CAN network can have several buffers or message mailboxes. On initialization, each mailbox is assigned an identifier that is either unique or is shared with certain other nodes. Also, each node is individually configured as a transmitter or receiver. This approach offers considerable flexibility in system design.