Special Purpose Communication Devices
Inverse Multiplexing means combining several low speed circuits into a high speed circuit
- most commonly used to provide T-1 circuits for wide area networks (T-1 circuits provide transmission rates of 1.544 Mbps by combining 24 lower speed circuits (64,000 bps).
- data is split and packets travel over several lower speed circuits for bandwidth
Multiplexing are done primarily using proprietary hardware ==>incompatibility problems in heterogeneous networks
two important standard propositions: BONDING (Bandwidth ON Demand Interoperability Networking Group) and PPP (Point-to-Point Protocol) (both split outgoing messages across several low speed circuits and combine incoming messages)