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<= /MAP>

<= IMG=20 height=3D100 alt=3D"GSW Study Notes Home"=20 = src=3D"http://www.geocities.com/SiliconValley/Monitor/3131/images/framesi= de.gif"=20 width=3D20 border=3D0>


	Networking Essentials=20 Notes
Section=20 1	Section=20 2	Section=20 3	Section=20 4
Section=20 5	Section=20 6	Section=20 7	OSI Layer=20 Model
Memory=20 Sheets:	Cables	IRQ's,=20 802, Cables, etc

OSI Model=20 Layers

Application=20 | Presentation=20 | Session=20 | Transport

Network=20 |=20 Data Link | Physical

=20

Layer=20	Function	Protocols	Network=20 Components
Application=20 User = Interface=20	used for applications specifically written to = run over=20 the network=20 allows access to network services that support=20 applications;=20 directly represents the services that directly = support=20 user applications handles network access, flow control and error=20 recovery=20 Example apps are file transfer,e-mail,=20 NetBIOS-based applications=20 = =20	DNS; FTP; TFTP; BOOTP; = SNMP;RLOGIN; SMTP;=20 MIME; NFS; FINGER; TELNET; NCP; APPC; AFP; SMB	Gateway
Presentation=20 Translation	Translates from application to network format = and=20 vice-versa=20 all different formats from all sources are made = into a=20 common uniform format that the rest of the OSI = model can=20 understand=20 responsible for protocol conversion, character=20 conversion,data encryption / decryption, expanding = graphics=20 commands, data compression=20 sets standards for different systems to provide = seamless communication from multiple protocol = stacks=20 not always implemented in a network = protocol=20		Gateway=20 Redirector
Session=20 "syncs and sessions" =	establishes, maintains and ends sessions across = the=20 network responsible for name recognition = (identification) so=20 only the designated parties can participate in the = session=20 provides synchronization services by planning = check=20 points in the data stream =3D> if session fails, only = data after=20 the most recent checkpoint need be transmitted=20 manages who can transmit data at a certain time = and for=20 how long=20 Examples are interactive login and file = transfer=20 connections, the session would connect and re-connect if = there was=20 an interruption; recognize names in sessions and register = names in=20 history	NetBIOS=20 Names Pipes Mail Slots RPC	Gateway
Transport packets;=20 flow control & error-handling	additional connection below the session layer=20 manages the flow control of data between = parties across=20 the network=20 divides streams of data into chunks or packets; = the=20 transport layer of the=20 receiving computer reassembles the message from = packets=20 "train" is a good analogy =3D> the data is = divided=20 into identical units=20 provides error-checking to guarantee error-free = data=20 delivery, with on losses or duplications=20 provides acknowledgment of successful = transmissions;=20 requests retransmission if some packets don=92t arrive=20 error-free=20 provides flow control and = error-handling=20	TCP, ARP, = RARP;=20 SPX NWLink NetBIOS / NetBEUI ATP	Gateway=20 Advanced Cable Tester Brouter
Network addressing;=20 routing	translates logical network address and names to = their=20 physical address (e.g. computername =3D=3D> MAC = address)=20 responsible for=20 addressing=20 determining routes for sending=20 managing network problems such as packet = switching,=20 data congestion and routing if router can=92t send data frame as large as = the source=20 computer sends, the network layer=20 compensates by breaking the data into smaller units. At = the=20 receiving end, the network layer=20 reassembles the data=20 think of this layer stamping=20 the addresses on each train car	IP; ARP; = RARP, ICMP;=20 RIP; OSFP;=20 IGMP; IPX NWLink NetBEUI OSI DDP DECnet	Brouter=20 Router Frame Relay Device ATM Switch Advanced Cable Tester
Data=20 Link data frames = to=20 bits	turns packets into raw bits 100101 and at the = receiving=20 end turns bits into packets.=20 handles data frames between the Network and = Physical=20 layers=20 the receiving end packages raw data from the = Physical=20 layer into=20 data frames for delivery to the Network layer=20 responsible for error-free transfer of frames = to other=20 computer via the Physical Layer=20 this layer defines=20 the methods used to transmit and receive data on the = network. It=20 consists of the wiring, the devices use to connect the NIC = to the=20 wiring, the signaling involved to transmit / receive data = and the=20 ability to detect signaling errors on the network = media=20	Logical Link Control=20 error correction = and flow=20 control=20 manages link = control and=20 defines SAPs 802.1 OSI = Model=20 802.2 Logical Link Control	Bridge=20 Switch ISDN Router Intelligent Hub NIC Advanced Cable Tester
Media Access Control=20 communicates with = the adapter=20 card controls the type of media being used: = 802.3 CSMA/CD (Ethernet) 802.4 Token Bus (ARCnet) 802.5 Token Ring 802.12 Demand Priority
Physical hardware;=20 raw bit stream	transmits raw bit stream over physical=20 cable=20 defines cables, cards, and physical=20 aspects=20 defines NIC attachments to hardware, = how cable is=20 attached to NIC=20 defines techniques to transfer bit = stream to=20 cable	IEEE 802=20 IEEE 802.2 ISO 2110 ISDN	Repeater=20 Multiplexer Hubs=20 Passive=20 Active TDR Oscilloscope Amplifier =

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= Comments and=20 suggestions? E-mail me at grantwilson21@yahoo.com I'm=20 sorry, but I can't answer specific network-related, or = exam-related=20 questions.
Last Updated: August 6, 2001 =	Grant Wilson, = Edmonton, AB=20 = Canada