What is a host?
any device that sends and receives information on the network.
What are Peripherals?
devices that are connected to hosts
Network devices link together using which variety of connections?
- Copper cabling – Uses electrical signals to transmit data between devices
- Fiber-optic cabling – Uses glass or plastic wire, also called fiber, to carry information as light pulses
- Wireless connection – Uses radio signals, infrared technology (laser), or satellite transmissions
- Wide Area Networks
- The most common example of a WAN is the Internet.
Telecommunications service providers
Wireless Local Area Network
Peer to Peer
no dedicated servers or hierarchy among the computers. In this type of network, each device has equivalent capabilities and responsibilities. Individual users are responsible for their own resources and can decide which data and devices to share. Because individual users are responsible for the resources on their own computers, there is no central point of control or administration in the network.
What are Peer-to-peer networks disadvantages?
- There is no centralized network administration which makes it difficult to determine who controls resources on the network.
- There is no centralized security. Each computer must use separate security measures for data protection.
- The network becomes more complex and difficult to manage as the number of computers on the network increases.
- There may be no centralized data storage. Separate data backups must be maintained. This responsibility falls on the individual users.
- is measured in bits per second and is usually denoted by any of the following units of measure:
- bps – bits per second
- kbps – kilobits per second
- Mbps – megabits per second
One MBps(Mega bytes per second)equals
- 8 Mbps
- Mega bits per second
also called unidirectional, is a single, one-way transmission. An example of _______ transmission is the signal that is sent from a TV station to your home TV.
When data flows in one direction at a time, it is known as _______. The channel of communications allows alternating transmission in two directions, but not in both directions simultaneously. Two-way radios, such as police or emergency communications mobile radios, work with ______ transmissions. When you press the button on the microphone to transmit, you cannot hear the person on the other end. If people at both ends try to talk at the same time, neither transmission gets through.
- When data flows in both directions at the same time, it is known as full-duplex. Although the data flows in both directions, the bandwidth is measured in only one direction. A network cable with 100 Mbps in full-duplex mode has a bandwidth of 100 Mbps.
- A telephone conversation is an example of _____________communication. Both people can talk and be heard at the same time.
is a number that is used to identify a device on the network. Each device on a network must have a unique IP address to communicate with other network devices.
IP addresses are divided into the following five classes:
- Class A – Large networks, implemented by large companies and some countries
- Class B – Medium-sized networks, implemented by universities
- Class C – Small networks, implemented by ISP for customer subscriptions
- Class D – Special use for multicasting
- Class E – Used for experimental testing
Dynamic Host Configuration Protocol
Automatic Private IP Addressing
Transmission Control Protocol
Internet Control Message Protocol (ICMP)
is used by devices on a network to send control and error messages to computers and servers.
Packet internet groper (ping)
is commonly used to test connections between computers.
shown in Figure 1, are devices that extend the range of a network by receiving data on one port, and then regenerating the data and sending it out to all other ports. This process means that all traffic from a device connected to the hub is sent to all the other devices connected to the hub every time the hub transmits data. This causes a great amount of network traffic. Hubs are also called concentrators, because they serve as a central connection point for a LAN.
use MAC addresses to forward a frame within a single network. Routers use IP addresses to forward frames to other networks. A router can be a computer with special network software installed, or a router can be a device built by network equipment manufacturers. Routers contain tables of IP addresses along with optimal destination routes to other networks.
Wireless Access Points
The wireless access point uses radio waves to communicate with radios in computers, PDAs, and other wireless access points. An access point has limited range of coverage. Large networks require several access points to provide adequate wireless coverage.
Unshielded twisted-pair (UTP)
Cable that has two or four pairs of wires. This type of cable relies solely on the cancellation effect produced by the twisted-wire pairs that limits signal degradation caused by electromagnetic interface (EMI) and radio frequency interference (RFI). UTP is the most commonly used cabling in networks. UTP cables have a range of 328 feet (100 m).
Shielded twisted-pair (STP)
Each pair of wires is wrapped in metallic foil to better shield the wires from noise. Four pairs of wires are then wrapped in an overall metallic braid or foil. STP reduces electrical noise from within the cable. It also reduces EMI and RFI from outside the cable.
Thicknet or 10BASE5
Coax cable that was used in networks and operated at 10 megabits per second with a maximum length of 500 meters
Coax cable that was used in networks and operated at 10 megabits per second with a maximum length of 185 meters
- The Ethernet architecture is based on the IEEE 802.3 standard. The IEEE 802.3 standard specifies that a network use the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) access control method. In CSMA/CD, hosts access the network using the first come, first served broadcast topology method to transmit data.
- Ethernet uses a logical bus or broadcast topology and either a bus or star physical topology. As networks expand, most Ethernet networks are implemented using an extended star or hierarchical star topology. Standard transfer rates are 10 Mbps and 100 Mbps, but new standards outline Gigabit Ethernet, which is capable of attaining speeds up to 1000 Mbps (1 Gbps)
IBM originally developed Token Ring as a reliable network architecture based on the token-passing access control method. Token Ring is often integrated with IBM mainframe systems. Token Ring is used with computers and mainframes
Fiber distributed data interface (FDDI)
is a type of Token Ring network. The implementation and topology of FDDI differs from the IBM Token Ring LAN architecture. FDDI is often used to connect several buildings in an office complex or on a university campus
An FDDI dual ring supports a maximum of 500 computers per ring.
The total distance of each length of the cable ring is 62 miles (100 km). A repeater, which is a device that regenerates signals, is required every 1.2 miles (2 km). In recent years, many token ring networks have been replaced by faster Ethernet networks.
Wireless Transport Layer Security (WTLS)?
is a security layer used in mobile devices that employ the Wireless Applications Protocol (WAP). Mobile devices do not have a great deal of spare bandwidth to devote to security protocols. WTLS was designed to provide security for WAP devices in a bandwidth-efficient manner.