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MCSE Boot Camp Training
PROTOCOLS ON LAYERS: Protocols on Layers*Application
Layer - (ASFAST) AFP SMNP FTP APPC SNMP TELNET and error RECOVERY.
Applications, e-mail, into user apps, initiates and accepts requests,
higher level protocols live here,
*Presentation Layer Layer6 - Protocol conversion. The redirector lives
here. Redirector grabs anything meant for network and not local PC,
(files, prints anything) and redirects to layers for proccessing to
right place. All the different formats from all sources and all kinds
are made into like a uniform common format that the rest of the OSI
model can understand.
*Session layer - Layer5 - Syncs & sessions. Connects two computers and
controls, who send when, for how long, how, speeds, and oversees total
control of packets. TCP, NWLink, named pipes, netBIOS and remember that
DLC lives here. This was one of the questions. Also remember that TCP (microsoft)
is like SPX (Novell) and IP (microsoft) is like IPX (Novell). The above
3 layers are the application-level network service users.
*Transport layer - (STANN) SPX TCP ATP NWLink NETBEUI "Trains" well I
try and remember that the data streams breaks up into what looks like
coaches of a train. The transport services layer. The error handling is
done here. Different protocols have different requirements for length of
data per packet, e.g. Token ring, Ethernet ATM all use different lengths
and these are formed and reformed in this layer
The above 4 layers use gateways. There are Qs on which layers use ( i.e)
App - Pres - Session - Trans.
There are also Qs on Physical = Repeater (or hub)
Data link layer = Bridge
Network = Router
*Network layer = (NINI) NWLink IP NETBEUI IPX Think of a big network,
where the traffic is routed to, this being done by adding source and
destination addresses, choosing best routes.(and uses routers.)
*Data Link Layer layer - Look at the movies on the CD with Net
essentials and see that DLL add CRC to other end of the data frames.
Bridges work here, and the book is very terse on explanations. Basically
the packets use network addresses (source and destination addresses) to
get around; they can move around the world using logical addresses and
are part of networking software, like Novell or Windows.This whole
"network structure" actually sits on top of,( like another thing) ,on
top of the LAN. The LAN being the basic underlying network, that's the
nitty gritty physical network, where the the actual Network cards talk
to each other. The LAN really is only local and the *DATA LINK LAYER
controls it. DLL is split into two LOGICAL LINK CONTROL and MEDIA ACCESS
CONTROL. This may seem difficult at first but its not too bad. Think
that the Media Access Control (MAC) controls the type of media being
accessed i.e. media being Token ring, Ethernet etc. also learn the
802.3~"Ethernet", 802.4 ~Arcnet (really only used by GM and obsolete),
802.5~Token ring, and 802.12 Fiber. The LOGICAL LINK CONTROL equates to
802.2 and is the "lowest level" controlling and managing the media.
*Physical layer - Layer 1 This is the hardware and physical cables.
Repeaters (or hubs) amplify attenuated or weak signal here. (Another
gift Q.) It just has to send 0 and 1, hi's and lows, on's and off's.
Data frames work at the two bottom layers and only inside the LAN using
Physical or MAC addresses (usually factory or hard wired addresses). On
page 176 looks like 10 of the gift Qs we got. These bottom 2 layers are
called networking services. P179 talks about SAPs.
*Protocols - Routable- IP, IPX, OSI, AppleTalk, DECnet, XNS.
Non-routable- NetBEUI, LAT. NetBEUI- Microsoft protocol designed for
small LANs; Nonroutable. IPX/SPX- Fast protocol for small and large
Novell networks; is Routable. Also known in NT as NWLink. *TCP/IP-
Internet protocol; is Routable. DECnet- Defines communications over FDDI
MANs; is Routable. Appletalk- Apple protocol designed for small LAN file
and print sharing.
*XNS - Designed by Xerox as an Ethernet protocol. Was replaced by
TCP/IP.
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