Notes:

---

• 1960s-1970s
  • IBM SNA, X.25
  • 1
  • , /

• 1970s-1980s
  • LAN printer, disk
  • Ethernet, Token Ring
  • LAN email, file transfer ,
  • : DEC VAX, DECnet

• 1980s-1990s
  • LAN, low speed PDN, Leased Line, high speed PDN
  • Application -> Application
  • flexibility, scalability, adaptability
  • LAN to LAN via WAN and Leased Line
  • FDDI, TCP/IP

Notes:

---

• Bridge : LAN LAN . LAN Network Address

• Hub : LAN Cable TP cable

• Ethernet Switch : LAN frame . Dedicated Bandwidth

• Router : Network Address . LAN WAN .

• ATM Switch : bps Gbps Switch. LAN WAN .

• Modem : digital analog

• CSU/DSU : CSU (128K ~) digital , DSU 56K/64K digital

• TA/NT1 : ISDN

• Multiplexer : 1

Notes:

---

• ISO 1974 (?) OSI 7 Layer Model
  • Model , Layer
  • Layer Peer-to-Peer Communication
  • Layer Interface
  • Transport Layer Segment, Network Layer Packet, Data Link Layer Frame, Physical Layer bit

• OSI 7 Layer Model DoD Layer (TCP/IP)
  • Dod Layer Network Interface OSI 7 Layer Data Link Layer Physical Layer , Internet Layer Network Layer .

---