Firewire in modern integrated military avionics

High performance communications, navigation, and identification (CNI) functions on modern military aircraft are increasingly required for mission readiness. The operation of simultaneous waveforms through an integrated avionics rack of shared resources becomes a test in moving data rapidly from one signal processing stage to the next. The IEEE 1394, or Firewire, is a commercial high bandwidth bus whose 64-bit addressing and maximum 400 Mbits/second throughput satisfies this demanding military avionics interconnect need. The challenge in applying this commercial product to integrated avionics is the requirement to seamlessly add message priority encoding. By having message priorities, the slower strategic communications links will not impair the performance of higher data rate tactical communications, thereby avoiding potentially life-threatening bottlenecks. The flight environment imposes additional challenges to ruggedize the cabling between integrated avionics racks and to utilize the full capabilities of the Firewire bus. A discussion of the physical, data link, network, and transport layers, as used in avionics applications will be done. Additionally, the versatility of 1394 in military avionics with its variable channel sizes, bandwidth on demand, hierarchical addressing, and upgrade to 800 and 1600 Mbps with a 64-bit wide data path, is emphasized. Finally, system maintenance advantages of 1394's hot pluggable features are discussed, with an eye toward cost reduction on the flight line and total operational time of the aircraft avionics systems