VCAT creates large capacity payloads over multiple smaller TDM signals. Defined for SONET/SDH, OTN and PDH path signals. Used to split bandwidth into right-sized groups for different services
IBM introduced Token Ring in 1984, standardized as IEEE 802.5 in 1989. Technology used special three-byte token frames passed around logical ring. IBM launched 4 Mbit/s version in 1985, later upgraded to 16 Mbit/s. Gigabit Token Ring standardized in 2001
ISDN was developed at Bell Labs in 1980 for digital transmission of voice, video, and data. Standardized in 1988 in CCITT Red Book, replacing analog T1/E1 lines. Initially aimed to digitize last mile of telephone network
Circuit switching establishes dedicated communication channels between network nodes. Originated in analog telephone networks for dedicated call circuits. Early telephone exchanges were typical examples of circuit switching
Network bridge creates single aggregate network from multiple segments. Bridging differs from routing, which allows networks to communicate independently. Bridging operates at data link layer (OSI model layer 2)
Computer network connects computers sharing resources over digital interconnections. Nodes include computers, servers, and networking hardware identified by addresses. Networks support various applications like email, video conferencing, and shared resources