Local Area Network

A wired LAN uses wires to connect the computers but a wireless LAN uses radio waves.

Dialog Control is the main function of Session layer.

Session layer manages dialogs between two computers and it is responsible for communication or conversation.

There are three forms of dialog.

1. Simplex dialogs : one way transfers, for example.. computer to printer ( computer will send data to printer and printer will receive the data ).

2. Half-Duplex Dialogs - Two-way transfers, Each device must take their turn. Both cannot transfer at the same time. for example..walkies-talkie

3. Full-Duplex Dialogs - Two-way simultaneous data transfers. Each device has it's own channel. for example.. telephone.

Networking.

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Some of the problems encountered in a Local Area Network include data insecurity and incompatibility of components/nodes. This depends on how the LAN is set up.

bus network

FTP is File Transfer Protocol. This is used for, say, if you have Norton (I use this reference a-lot for those of you who read my posts) and you want to upgrade, some people make a mistake and install over the old version. NEVER A GOOD IDEA! This can, and USUALLY WILL cause a software conflict. In this case, your software could be rendered useless. So, you would contact customer support. The easiest way is to "Chat With Technical Support". If they feel they can help you, they may ask you permission to access your computer. With the ability to access your computer, they can control your mouse, run programs, remove, and install. FTP allows you to open a specified port (usually mandated by the manufacturer) to allow access to your PC to fix this. Another use for FTP is for Online Gaming that use account's. With FTP, you are able to kick people with vulgar language, being racist, or breaking any other rule in the T&C's.

HTTP is "Hypertext Transfer Protocol" which is the directory that servers use to send information to your computer that you request.

If you are running Windows XP, you can click "Start", and open "My Documents". This view is called Windows Explorer, not to be confused with Internet Explorer. If you look at the top of the Explorer windows, just like in a web browser, you will notice something like "C://admin/my documents/music/goo goo dolls/song1.aiff" This is called a directory, it points to the location of a file.

If you are running Windows Server 2008 (or any other earlier version for that matter), the directories will begin with http:// instead of C://. C:// is the C drive (usually your main HDD) where as the http:// points to a directory within the servers of the web.

http is NOT to be confused with .htm, .html., xml, or .xhml which are file EXTENSIONS, and not DIRECTORIES.

Oh, but they do crash into each other from time to time. In which case both senders stop, wait for a random standoff time, then attempt to resend.

Traditionally, two switches can be connected together with a crossover cable.

A crossover cable should be used whenever two of the same network devices need to be connected together. e.g. Connecting a router to another router, a switch to another switch or a PC to another PC.

Using a crossover cable is not always necessary however. Most new network devices include a feature named Auto-MDIX (Medium Dependant Interface Crossover). Auto-MDIX detects what type of cable is connected and automatically changes its own configuration to enable data transmission to the other device. i.e. It does not matter if you use a straight through cable or crossover cable on Auto-MDIX enabled devices. Both will work.

its a switch

Fiber Optic cables carry data as light.

by combing these layers the functionality is performed by a

single layer and overhead is reduced.The disadvantage is

more functions need to be performed by single layer

The TCP/IP model was adopted and condensed into 4 Layers.

1. Link layer ( Layer 1and 2 of the OSI model)
2. Internet Layer (Layer 3 of the OSI model)
3. Transport ( Layer 4, 5 and 6 of the OSI model)
4. Application ( Layer 7 of the OSI model)

http://en.wikipedia.org/wiki/TCP/IP_model#Link_Layer

Ethernet AUI

AUI cables have a D-type 15 pin connector. Pin assignments are as follows:Pin 1Control In circuit ShieldPin 2Control In circuit APin 3Data Out circuit APin 4Data In circuit ShieldPin 5Data In circuit APin 6Voltage CommonPin 9Control In circuit BPin 10Data Out circuit BPin 11Data Out circuit ShieldPin 12Data In circuit BPin 13Voltage PlusPin 14Voltage ShieldPins 7, 8 and 15 are not used.

1) Client makes a UDP Broadcast to the server with a DHCPDiscover, or Discover packet.

2) DHCP offers to the client.

The server sends a DHCPOffer including other configuration parameters (DHCP Options) for the client per the servers configuration file

3) In response to the offer Client requests the server.

The client replies DHCPRequest, unicast to the server, requesting the offered address.

4)The server sends DHCPAck acknowledging the request which is the clients final permission to take the address as offered. Before sending the ack the server double checks that the offered address is still available, that the parameters match the clients request and (if so) marks the address taken.

A good reference for DHCP information is Droms and Lemon "The DHCP Handbook". BoydK

Layer 4 (Transport) is responsible for correction.

See the OSI layer.

The MAC address is the base addressing.

IP addresses ride on top of the MAC Addresses.

You need to configure a static IP address on both items to enable them to talk to each other. I.E. set the PC to 192.168.1.2 and the printer to 192.168.1.3 Use 255.255.255.0 for the subnet mask. The gateway can be set to 192.168.1.1 although this setting is not needed for a crossover cable. The Problem is that I don't have the printer cable and the only way to attach the printer is via an ethernet crossover cable. the printer is from an office and was networked previously. I did a configuration print out of the printer and I set up the IP address already given to the printer on the printout. I gave my laptop the same IP address and subnet as the print out and set up a network using the network wizard but I still cannot see or access the printer.

There are more than 3 protocols at the application layer. Three well-known protocols are:

HTTP - web page traffic

FTP - file transfer traffic

SMTP - email transfer

A. Traffic is classified based on quality of service requirements.

D. Digital movies are always assigned to the high-priority queue for processing.

Convert each decimal number to a binary number separately. You can use Windows calculator for this (in the menu you will find a command to switch between standard calculator and scientific calculator). Each group of bits must be completed to 8 bits - fill out with zeroes on the left, until you have 8 bits (so for the the second part, the calculator will give you 1101011 - add a zero to the left to get 01101011).

If you want to do the conversion with pencil and paper, ask a separate question, or research existing questions, something like "how do you convert decimal to binary".

Devices- 6

W= n(n-1)/2

whereby W is number of cables

n is number of devices

solution

W= 6(6-1)/2

=6(5)/2

=3(5)

=15

15 cables

Internet browser.