I have compiled these notes based on experiences from MCSE qualified people and my own experience when I sat this exam. Some contributions are already posted on the Internet, they have all taken the NE exam. Some have taken three attempts to pass, these are their suggestions on what you should know. Some said they were asked nothing on wireless networks and some said they only had one or two questions on OSI Model, I had 4 questions on Netbios Naming systems which I struggled with, read through them all if you have time because they are great revision notes. You may notice some duplication on certain subjects, this is only because I've included different peoples notes.
 

Note: I have tried to hi-light most key words for our BRAINS to remember!

1. Standards and Terminology

Peer to Peer - Use when there are less than 10 computers and Security is not an issue, also called Workgroups.
Client/Server - Use when there are more than 10 computers or it may be expanded in the future and Security is an issue.
                             Administration centralized, Dedicated, File , Print, Fax Servers, Auditing and Monitoring and more.

Bus - Signal Bounce, Terminator, Passive, Linear, Segment, Trunks, Repeater, Barrel Connector. 1 PC fail/network
Star - Hubs, Central Point, Central point fails - Network fails, 1 PC fails on Hub network continues.
Ring - Token passing, Clockwise, only 1 PC can send, 1 PC can be masked out and not effect network.

Active Hubs - Regenerate and transmit, Same as repeater 8 - 12 ports, can be called multiport repeater, need power.
Passive Hubs - Wiring panels, punchdown blocks, no AC power source needed, are basic connections only.

Crosstalk = Overflow of signal from an adjacent wire
Attenuation = The weakening or distorting of a transmitted signal over extended distance.
Beaconing = The process of signalling computers on a ring system that token passing has been interrupted by an error.
Jitter = Instability in a signal wave form over time that could be caused by signal interference or an unbalanced ring in FDDI or Token Ring environments.
A UNC (Universal Naming Convention) \\computer name\share name for example \\Sales1\MSWord

User Level Security - Security is implemented by the Admin - security is based on login user name and password (NT)
Share Level Security - Each user has control of their shared resources (or "share") - used on peer to peer (Win95)

Connection oriented communication: Is reliable delivery
Connection-less orientated communication Is unreliable delivery
PPP - Supports dynamic IP addressing and SLIP Does not. Also SLIP does not support compression but CSLIP does.
CSMA/CD -Carrier-sense multiple access with collision detection - check the cable for traffic - if there is no traffic it can send
CSMA/CA - Carrier-sense multiple access with collision avoidance - signals the intent so send data b4 sending to help avoid collisions - is slower and less popular than CSMA/CD
ODI - Open Data Link Interface (Novell) are designed to bind multiple protocols to a single NIC.
NDIS - Network Driver Interface Specification (Microsoft)  are designed to bind multiple protocols to a single NIC.
  Will bind multiple protocol stacks and NICs

2. OSI Model - 7 layers, This is my method  All People Send Their Network Data Physically

The most detailed site for Protocols ISO *Brilliant * http://studsys.mscs.mu.edu/~chong/mscs210/iso-osi.html#model
 

LLC - (Logical Link Control) Upper sublayer of DLL - manages DL communication and defines the use of logical interface points - defined by 802.2
MAC - (Media Access Control) Lower sublayer of DLL - provides shared access for the NIC Physical layer - is responsible for delivering error-free data between 2 computers - defined by 802.3, 802.4, 802.5, and 802.12
 

3. PROTOCOLS ON LAYERS: Protocols on Layers

I learned OSI very well, NE Page 172-175. It Pays to also know where the network protocols live. They will give you a picture of it somewhere in your exam possibly, if you forget the order:

(All People Send Their Network Data Physically)

Application layer: layer7 Applications, e-mail, into user apps, initiates and accepts requests, higher level protocols live here, Application - (ASFAST)   AFP SMNP FTP APPC SNMP TELNET and error RECOVERY.

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. NDIS3,  Look p215.

 
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
 

Question: Where does SMB reside? Where do you find DLC?

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.

4. IEEE 802 SPECIFICATIONS IEEE 802.X
 

5. Planning Cables

Ethernet topologies:
 

Type	MHz	Cable Type	Length	Connector
10BaseT	10	Cat 3,4 or 5 UTP (STP)	100 meters	RJ-45
10Base2	10	thin-coax (RG-58)	185 meters	BNC
10Base5	10	thick-coax (standard Ethernet, thicknet)	500 meters	DIX or AUI
10BaseFL	10	fiber-optic	2000 meters	expensive
100BaseT4	100	4-pair Cat 3,4 or 5UTP	100 meters?	RJ-45
100BaseTX	100	2-pair Cat 5 UTP or STP	100 meters?	RJ-45
100Base	100	2-strand fiber-optic cable	2000 meters?

RG-58 /U = Solid copper core - 50ohm impedance
RG-58 A/U = Stranded wire core
RG-58 C/U = Military spec. of RG-58 A/U
RG-59 = Broadband transmission such as cable TV
RG-6 = Larger in diameter and rated for higher frequencies than RG-59, but used for Broadband transmissions as well
RG-62 = arcane networks

What is the difference in RG58U and RG58AU?

A/U signifies a stranded wire core instead of solid for Thinnet. RG 58 U cable (solid core conductor) is NOT compatible with for Thinnet and is different that RG 58 A/U which IS used for Thinnet *HINT* replace RG58 U with RG58 A/U

1 meter =3.281 feet
Know the different categories of UTP cable and what bandwidth they're capable of.
 

Category	Mbps	Type	Physical	Length	Connector
1	?	Voice	Telephone cable	Help?	MIC
2	4	Data	4 twisted-pairs	Help?	MIC
3	10	Data	4 twisted-pairs - 3 twist per foot	100 meters?	RJ-45 or RJ-11
4	16	Data	4 twisted-pairs	100 meters?	RJ-45 or RJ-11
5	100	Data	4 twisted-pairs of copper wire	100 meters?	RJ-45 or RJ-11

6. IBM Cabling System
 

7. WIRELESS: Networks

Infared - Laser - Narrow Band - Spread Spectrum.

Infared - Line of Sight, Clear line of sight between transmitter and receiver
Scatter infared - Bounce off walls and ceilings, 100 feet, slow because of all the bounces
Reflective - Optical tranceivers transmit to receivers which redirect signals to appropriate computer
Broadband - Optical Telepoint, can handle high quality multimedia and match cable networks
 

Laser- As in infared, requires line of sight

Narrow Band (Single Freq) Radio - No line of sight needed, 5000 square, not pass through loadbearing walls 4.8 Mbps
Spread Spectrum Radio - Range of requencies, switches to hops, compatible with Netware/NT can transmit at 250 Kbps
to 2 Mbps over 2 miles or 400 feet indoors, add access point to Netware and they can comunicate via Credit Card NIC.

Point To Point Transmission: Direct communication with each other as apposed to broadcasting to range.

Point to Point - Comunicates directly from PC to PC through walls and ceilings, fast error free transmission, 1.2 to 38.4 Kbps upto 200 feet indoors and upto a third of a mile outdoors, also communicate with printers, barcode readers etc.

Wireless Bridge:

Connects networks upto three miles apart, Long range can cover 25 Miles Ethernet and Token Ring, cost can overcome
or outway need for leased line or T1, although T1 can provide a much faster transfer rate 1.544 Mbps.

Packet Radio: Uplinked to satellite, broadcast only to device which has correct address.
Cellular: CDPD same as phone, subsecond delays only, real time transmission, can tie into cabled network.
Satellite: Microwave, most common in USA, 2 X directional antennas, building to building, building to satellite

8. IRQ (Interrupt Requests)
 

9. NIC: Network interface Cards

16 Bit and 32 Bit, ISA, EISA, PCI, MCI, DIX, AUI, BNC, RJ45, Faster = Bus Mastering, Ram Buffering, Onboard CPU, Bus Mastering cards can offer 20 - 70 % performance inprovement.

EPROMS -  For diskless workstations to enable boot from Elec Prog Read Only Memory and no physical disks installed.

Incorrect frame types can really throw off an IPX/SPX network.

IPX/SPX is great for Peer-to-Peer networking if NetBEUI is not availabe

NetBEUI is a Transport protocol and is not routeable mainly used on Microsoft networks.

Mesh - uses routers to dynamically select the best path for the data

Know what a Mesh topology looks like (I had one that showed an exhibit of a mesh and asked me what it was). Check out page 782 of the SSK. Mesh Topology

A Subnet Mask is used to mask a portion of the IP address so that TCP/IP can distinguish the network ID from the host ID. TCP/IP hosts communicate by using the subnet mask to determine whether the destination host is located on a local or remote network. The following is a valid subnet mask: 255.255.0.0.

10. LAN Enhancement Components
 

Spanning Tree Algortithm - was developed for bridges to determine the most efficient network in path when there are multiple paths to choose from.

11. Packet Switching Networks

Packet Switching - Packets are relayed across network along the best route available.

Repeater = Physical layer - takes a weak signal and regenerates it - doesn't translate or filter anything - can move packets from on physical media to another (i.e. can connect thinet to fiber-optic) - they are cheap - will pass a broadcast storm
Bridge = Data Link layer - does everything a repeater does - reduce traffic by segmenting the network by using a routing table- regenerate the signal at the packet level - not suited to WANs slower than 56K - will pass broadcast storms - read the source and destination of every packet - pass packet with unknown destinations - connect dissimilar networks (i.e. Token Ring and Ethernet)
Router = Network layer - does filtering and isolating traffic - forwards particular protocols to particular addresses (other routers) - connect network segments - not all protocols are routeable (LAT and NetBEUI) - are used in complex network situations because they provide better traffic mgmt. than brides - don't pass broadcast traffic.
Brouter = combines best qualities of both a bridge and a Router - can act like a Router for one protocol and bridge all of the others (nonroutable) - delivers more cost-effective