Page 7 of 18 March 2001 Fibre Channel: Why another interface? Transmission speeds are further reduced as more devices share the network. Because all of the devices on the network transmit and receive data over a single, shared wire, packets begin bumping into each other more frequently. As a result of these data collisions, data packets can be delayed, delivered out of sequence, lost or destroyed, or otherwise modified as they move through the network from their source to their destination. A significant amount of processor involvement is required to reassemble the data into the correct order and perform error correction once the data reaches its destination. All of these factors make traditional networks particularly unsuitable for use with centralized backup applications that transfer large amounts of data to tape drives for storage. Traditional networks cannot provide the performance needed to keep pace with the rapidly increasing data transfer rates of today’s tape drives. They are not fast enough to keep these high-performance tape drives streaming. The following table summarizes the advantages and disadvantages of traditional network technology. As with parallel data buses, the disadvantages make traditional networks unsuitable for rapid, error-free transfer of large amounts of data to and from storage devices in today’s storage environments. Traditional network advantages and disadvantages Advantages Disadvantages •    Longer distances between connections •    Encapsulated data allows heterogeneous systems transferring many different types of data to share the network •    Nearly unlimited number of device connections •    Simple, inexpensive cables and connectors •    Flexible, scalable networks using switched topologies •    Simple device addressing using unique identifiers for each device •    Relatively slow data transfer (1.25 to 12.5 MB per second for 10/100 BaseT Ethernet) •    Shared cable for transmitting and receiving data •    Potential for delayed, out of sequence delivery, and lost or destroyed data packets •    High error rates •    Shared bandwidth •    Software intensive •    High CPU overhead for signal processing and error handling Because individual packets may be delayed, damaged, or lost during transmission, traditional 10/100 BaseT Ethernet networks cannot guarantee error-free, sequential delivery of transmitted data. p1   p2   p3   p4   p5   p6   p7   p8   p9   p10   p11   p12   p13   p14   p15   p16   p17   p18