what is FDDI

It is high performance fiber optic token ring network.  It is used with high bandwidth.  FDDI is implemented without hubs, although you can use devices called concentrate to perform a similar function.

Carrier Sense Multiple Access with Collision Detection (CSMA/CD)

In local area networks a method used by computer's access to the communication channel. With CSMA/CD, each component of the network (called a node) has an equal  right to access the communication channel.  If two computers try to access the network at the same time, the network uses a random number to decide which computer gets to use the network first.

This channel access method works well with relatively small to medium sized networks (two or three dozen nodes). Large networks use alternative channel access methods, such as polling and token passing to prevent overloading or locking up the  system.

What is Ethernet

A networking hardware communication, and cabling standard, originally developed by xerox corporation that can link  up to 1,024 node in a bus network.  A high-speed standard using a baseband (single channel) communication technique.  Ethernet provides for a raw data transfer rate of 10 megabits per second (mbps), with actual throughout in  the range of 2 to 3 megabits per second. Ethernet uses carrier sense multiple access with collision detection (CSMA/CD) techniques to prevent network failures when two devices try to access the network at the same time.

What is server

A term server refers to any device that offers a service to network users.  A server can be hardware, software or both.  Server can be PCs doing double duty, or they can be specific purpose devices,  The most common ones are file servers, print servers and gateways(also known communications server).

.What is work station

A workstation is a computer used as a node on a network primarily used to run application programs.  In the IBM Token Ring Network, any IBM PC compatible computer can be used as a workstation.

Class B Subnetting

Example:

                                       255.255.128.0  (/17)
Network Address:

                                        172.16.0.0 = Network Address
                                        255.255.0.0  = Subnet Mask

Subnet: 

                                        255.255.128.0 (/17)

                                        IIIIIIII.IIIIIII.I0000000.00000000
                 
Subnet:                            2x1=2


Host:                               2 power 15-2= 32,766 (7 bits in thirad octate and 8 bits in the 4 octate.

Valid Subnet:

Subnet                         0.0                                128.0
First Host                    0.1                                128.1
Last Host                    127.254                        255.254
Broadcast                    127.255                        255.255

Subnetting

Class                        Formet                                 Default Subnet Mask
A                      network.host.host.host                   255.0.0.0
B                      network.network.host.host             255.255.0.0
C                      network.network.network.host      255.255.255.0

Valid Subnet-   256-subnet mask=block size or increment number.  An example would be256-192=64 .  The block size of a 192 mask is always 64. start counting at '0' in block of 64 until you reach the subnet mask value and these are you subnets. 0,64,128,192.

Broadcast Address-  Now here the realy easy part since we counted our subnets it the last section as 0,64,128,and 192.  The broadcast address is always the number before need the subnets for example of '63' because the next subnet is 128 and so on and remember the broadcast address the last subnet is always 255.

Valid Host-  Valid host are numbers between the subnets omitting the all '0' ans '1s'.  For example: If 84 is the subnet number and 127 is the broadcast address. Then 65-126 is the valid host range.  It is always the number between the subnet address and the bradcast address.

Class C:

Example:  255.255.255.128 (/25)
                  IIIIIIII:IIIIIIII:IIIIIIII:I0000000

Since 128 is 10000000 in binary, there is only 1 bit for subneting and 7bits for hosts.  We are going to subnet the class C network address.

                 192.168.10.0      = network Address
                 255.255.255.128=Subnet Mask


How many Subnet

Since 128 is 1bit on (10000000) the answer would be 2x1=126hosts.

How many host per subnets?     

256-126=128, Remember willbe start at '0' and count in our block size.  So our subnets are 0,128.

What is the broadcast address for each subnet?

"The number right before the valuea of the next subnet is all host bits turned on and equal the broadcast address.  This way the valid hosts are obvious.  The following Table shows the '0' and 128 subnets.  The valid host ranges of each and the broadcast address of both subnets.

Subnets                   0                                                 128
First host                 1                                                 129
Last host                 126                                             254 
Broadcast host        127                                             255