CSE 05 Unit 3
What is a private IP address?
An IP address that cannot be routed over the Internet.
Why is wireless slower than wired?
Because interference affects a wireless signal. Data must be re-transmitted, and that takes extra time.
Do you need a domain name?
For client-style Internet activities, such as Web browsing, email, and downloading, you do not need your own domain name. Today, social networking sites give ample opportunity for making your presence known on the Internet.
What is a network?
Links things together.
What are the options for wireless channels?
Radio signals and microwaves.
Can you use an alternate DNS server?
Surprisingly, you might be able to bypass DNS outages, blocks, and hacks by changing your DNS server.
How does Ethernet work?
Usually arranged in a star topology with computers wired to central switching circuitry that is incorporated in modern routers. Data sent from a computer on the network is transmitted to the router, which then sends the data to the destination device.
How are packets transported?
TCP (transmission control protocol) is also responsible for establishing a connection, transferring packets, and closing the connection when the transmission is complete. Most of the data that flows over the Internet is under the control of TCP. An alternative transport protocol, UDP (User Datagram Protocol) is faster than TCP but does not perform error checking and cannot reorder packets if they are received out of order.
What are the options for wired channels?
Telephone cable, network cable, coaxial cable, and fiber-optic cable.
What is the domain name system?
A large database of unique IP addresses that correspond to domain names.Ex: nike.com.
What is the difference between a sensor and a tag?
A sensor, such as a thermometer or heart rate monitor, actively collects data. A tag contains passive data.
Packet loss
A situation in which data bits are lost in transit, requiring them to be resent, which significantly increases the time required for an intact message to arrive at its destination.
What is a packet?
A small unit of data transmitted over a network.Contains the address of its sender, the destination address, a sequence number, and some data.
How fast is Wi-Fi?
Although Wi-Fi 802.11n is capable of 600 Mbps speeds, its actual performance is normally 50-100 Mbps. 802.11ac (faster) has a theoretical speed of 7 Gbps, but actual speeds are 400-800 Mbps.
How are computer networks classified?
By their size and geographic scope.
What are the advantages of wired channels?
Cables can be shielded against interference and encased in protective casings for installations that are outdoors and underground.Are dependable. Their carrying capacity and speed are not affected by airborne interference from rain, snow, or electrical devices.Are more secure than their wireless counterparts because a device can join a wired network only if it is physically connected by a cable.
How do microwaves transport data?
Can be aimed in a single direction and have more carrying capacity than radio waves. However, microwaves cannot penetrate metal objects and work best for line-of-sight transmission when a clear path exists between the transmitter and receiver.Installations usually provide data transport for large corporate networks. They are also used to transmit signals between towers in cellular and wide-area wireless installations.
What does connection speed measure?
Capacity (speed). A common term for the capacity of an Internet connection, usually measured in Mbps or Gbps.
Arrival protocol
Convert data into standard formats that can be used by applications, such as email, Web browsers, and Skype.
What should you know about network nodes?
DTE (data terminal equipment): Computers and other devices connected to a network to send or receive data. DCE (data communication equipment): Devices, such as routers and hubs, that are used to manage data that flows over a communications network.
Can a network use more than one topology?
Data can flow over multiple networks that have different topologies.
Jitter
Deviations in the timing of a digital signal that can interfere with communications, especially voice over IP.
What topology is best?
Every topology has strengths and weaknesses, so there is no best network topology.
What are your Internet connection options?
Fixed internet access, portable internet access, and mobile internet access
What about other DCEs (data communication equipment)?
Hub, switch, bridge, repeater, and wireless access point (WAP).
Who supervises Internet standards?
ICANN, the Internet Corporation for Assigned Names and Numbers. ICANN is headquartered in Los Angeles and subject to oversight by the U.S. Department of Commerce.
What is a communications port?
In the context of computer networks, a virtual location for data that arrives or leaves the device; common ports include 21 for FTP, 110 for email, and 80 for Web data.
Exactly what is an Internet address?
Internet addresses are controlled by IP (Internet Protocol), which—along with TCP—is part of the Internet protocol suite. IP defines two sets of addresses: IPv4 and IPv6.
What are the components of the Internet?
Internet backbone (tier 1): The major communications links that form the core of the Internet. Internet service providers (ISPs) (tier2): Companies that provide Internet access to businesses, organizations, and individuals. Internet exchange points (IXPs) (tier 3): Nodes on the Internet where data from one service provider is transferred to a different service provider.
Can you get mobile broadband for your laptop?
Isn't just for your smartphone. You can also use it to access the Internet from a laptop or desktop computer.
Does every Internet user need an IP address?
It is more accurate to say that every device on the Internet needs an IP address.
Transport protocol
Make sure data gets to its destination by establishing standards for dividing data into chunks, assigning addresses, and correcting errors.
Why are upload and download speeds different?
Most Internet connections are asymmetrical with upload speeds considerably less than download speeds. Asymmetric connections discourage subscribers from setting up Web and email servers that would transmit lots of outgoing data.
Are LANs (local area networks) regulated by the government?
Most wireless LANs use the 2.4 GHz and 5.0 GHz unlicensed frequencies so that they can be set up without applying to the FCC for permission. The few unlicensed frequencies are crowded, however, and neighboring networks that are forced to use the same frequencies pose security risks.
How are packets created?
One of the core Internet protocols, TCP (Transmission Control Protocol) is responsible for dividing files into chunks, adding headers containing information for reassembling packets in their original order, and verifying that the data was not corrupted while in transit (a process called error checking). When data is sent over the Internet using TCP, it will reliably reach its destination.
How does Wi-Fi work?
One option is to use wireless mesh topology in which devices broadcast directly to each other A second option for Wi-Fi networks is a star topology in which a centralized broadcasting device—a wireless access point—coordinates communication among network devices.
What can communication protocols do?
Protocols set standards for encoding and decoding data, guiding data to its destination, and reducing the effects of interference.
How does the domain name system work?
Scattered around the world are several domain name servers that maintain lists of all domain names and their corresponding IP addresses. In addition, frequently used domain names are stored by ISPs, educational institutions, organizations, and Internet companies such as Google.
Physical protocol
Specify cable and signal standards for the channels that carry data.
Do I0T networks use Wi-Fi technology?
Wi-Fi is fairly power hungry, so it is not an optimal IoT technology.
What is the range of a Wi-Fi network?
Wi-Fi signals may reach up to 300 feet (90 meters) from the router. Thick cement walls, steel beams, and other environmental obstacles can drastically reduce this range.
What is bandwidth?
The data transmission capacity of a communications channel. Digital signals are measured in bits per second; analog signals in Hertz.
How fast is mobile broadband service?
The most recent of these generations are 3G and 4G. Mobile broadband speed decreases at the edges of coverage. It can be reduced by obstacles, such as trees, hills, walls, and even metal roofs. Electromagnetic interference from speakers, microwave ovens, and other electrical devices can reduce speeds, too. Rain, snow, and high humidity can also reduce speeds.
What is network topology?
The physical structure of a network including its devices and connections.
How does mobile broadband work?
The signals flow between a device, such as a mobile phone, and a cellular radio tower (1). Data signals are passed to ground stations (2). Where they are forwarded over a packet-switched network to the Internet (3).Voice signals may be routed to a circuit-switched network (4).
What are the characteristics of LANs (local area networks)?
They have a topology. They use communication protocols to ship packets. They require communication channels such as cables or wireless signals. They also include data communication equipment such as routers and modems.
How does licensing affect wireless connections?
To broadcast at most frequencies, including those used by radio and television stations, a license is required.Wireless connections use unlicensed frequencies that are available for public use.5 GHz is subject to less interference from other devices, but it has a more limited range.
Why not just send an entire message?
Unfortunately, circuit switching is rather inefficient. For example, when someone is on hold, no communication is taking place—yet the circuit is reserved and cannot be used for other communications. A more efficient alternative to circuit switching is packet switching technology, which divides a message into several packets that can be routed independently to their destination.
