COMPONENTS USED TO ENLARGE AN EXISTING LAN
HUBS                            REPEATERS		BRIDGES
ROUTERS                        BROUTERS		GATEWAYS
OSI MODEL		TCP/IP LAYERING
7.  APPLICATION (gateways, & 1-6 sometimes)		Windows Sockets             NetBIOS	4.  APPLICATION
(initiator of requests)        FTP SMTP		application                applications
6. PRESENTATION		Windows Sockets              NetBT
(translates & converts protocols, encrypts)
5. SESSION		TCP                              UDP	3.  TRANSPORT
(coordinates communication)		(3-way handshake)
4. TRANSPORT		IGMP                                               ICMP
(accurate error-free delivery, TCP,SPX prot.
3.  NETWORK     (router and brouter)		IP	2.  INTERNET
(translates addressing messages, IP, IPX)		ARP
2.  DATA-LINK (bridge and brouter) NICs, IEEE
(transmits data, adds CRC to packet)		LAN Technologies        WAN Technologies
1.  PHYSICAL    (repeaters and hubs)      NICs		Ethernet, Token Ring            Serial Lines, Frame Relay	1.  NETWORK
(data transfer bit by bit, H/W connections)		FDDI                                                ATM
OSI = OPEN SYSTEMS INTERCONNECTION		TCP/IP = TRANSMISSION CONTROL PROTOCOL/
		INTERNET PROTOCOL
OSI LAYER		FOCUS
7. APPLICATION		Program-to-program transfer of information
		Initiator or requests
6. PRESENTATION		Text formatting and display code conversion
		Translator, converts dissimilar protocols, & encrypts
5.  SESSION		Establishing, maintaining, and coordinating
		communcation
4.  TRANSPORT		Accurate delivery, service quality
3.  NETWORK		Transport routes, message handling, and transfer
2.  DATA-LINK		Coding, addressing, and transmitting information
1.  PHYSICAL		Hardware connections