Chapter 12 Client/Server Networks and Topologies (Part 1)

Intranet

A private network that uses Internet technologies to share company information among employees.

Application server

A repository for applications such as Microsoft Word that allows them to be used over a network. Time consuming to install software. On each computer and this server solves this issue.

Active topology

A ring topology is a active topology. Nodes participate in moving data through the network. Each node on the ring is responsible for retransmitting the token or the data to the next node on the ring.

Print server

A server that manages all client-requested printing jobs for all printers on the network. Print queue software holding area for jobs. Prioritize.

Protocol

A set of rules governing the exchange or transmission of data between devices.

CSMA/CD

Carrier sense multiple access with collision detection: A node connected to the network uses carrier sense "listens"to verify that no other nodes are currently transmitting data signals. If two devices begin transmitting data signals at the same time, signals collide.

Authentication server and file server.

Keeps track of who is logging on to the network. File server holds files.

Cloud servers

Maintained by hosting companies. Small businesses use these to save money.

What topology is best?

Star topologies are the most common, because large networks are adding new users. Bus networks are nearly obsolete.

What does a bus topology look like?

-All computers are connected in sequence on a single cable. -Legacy technology. Does not easily support wireless connections. Example: Still found in manufacturing facilities where groups of computer controlled machines are connected. —Bus networks are simple and low cost. If break in single cable, all computers shut off.

What does a ring topology look like?

-Computer and peripherals are in a ring and data is passed using a special data packet called a token. -Ring topology provides a fairer allocation of network resources than does a bus topology. —Advantage is performance is even with a large number of users. —Disadvantage is one computer fails, the entire network fails. Hard to fine problems in the network.

What are advantages of star network?

-The failure of one computer does not affect the rest of the network. -It's easy to add nodes to the star networks. -Performance remains acceptable with a large number of nodes. -Centralizing communications through a switch makes troubleshooting and repairs easy. Technicians pinpoint a communications problem just by examining the switch, as opposed to searching for a particular length of cable that has broken in a ring network. -Cost used to be a barrier, but the price of cable has gone down and wireless nodes are replacing wired nodes.

Data collisions

-When two computers send data at the same time and the sets of data collide somewhere in the media. —A limitation of Bus networks is that data collisions can occur fairly easily due to (1) cable.

(4) advantages business installing networks.

1) Enable reesources to be shared: Printers, internet $$. 2) Facilitate knowledg sharing: Network databases serve many. Example: Student record database. 3) Enable software sharing: Do not have to install program on every computer. 4) Enable enhanced communication: Social networking tools, e-mail and IM deployed on network.

List the (6) key components of a Client/Server Network.

1) Servers 2) Network topologies 3) Transmission media 4) Network adapters 5) Network navigation devices 6) Network operating system.

passive topology

A bus network topology is passive topology. Each node passively listens for, then accepts, data directed to it. A bus topology is considered a passive topology. The nodes attached to the bus network do nothing to move the data along. The terminator said a device that absorbs a signal so that its not reflected back onto parts of the network that already have received it.

Database server

A computer in a client/server environment that is responsible for running a DBMS to process SQL statements and perform database management tasks Example: College needs to access records at same time.

How does a token move around in ring topology?

A token is passed form computer to computer around the ring until its grabbed by a computer that needs to transmit data. The computer "holds" on to the token until it has finished transmitting the data. Only one computer in the ring can hold the token at a time.

Electronic Data Interchange (EDI)

Allows the exchange of large amounts of business data (like orders for merchandise) in a standardized electronic format. Example: Walmart has an extranet that allows for the exchange of large amounts of business data (merchandise orders) in a standardized electronic format. Employers, vendors and contractors share information.

WAN (Wide Area Network)

Comprised of a number of users over a wide physical area or separate LANS that are miles apart. Businesses use WAN to connect tow or more geographically distant locations. Example: College might have a east campus (LAN) and west campus (LAN) located in different towns and share a WAN.

Client-server network/server-base network: A server both stores and shares resource on a network. Centralized vs. decentralized

Example: Data files are stored on a server. Backups for all users on a business network can be performed by merely up all files on that computer. The server can coordinate data security. Client/server networks are centralized and P2P networks are decentralized.

Dedicated server

Fulfills (1) specific function like e-mail. Used for repetitive tasks of demands a lot of time from a CPU. Example: Authentication, file, print, e-mail, communications, cloud.

LAN (Local Area Network)

Group of computers linked together over a small geographical area. Computer lab at school or office building floor.

Communications servers

Handles all communications between the network and other networks including managing internet connectivity. All requests for information fro the Internet and all messages being sent through the internet pass through the communications server.

Web server

Hosts a website so that it will be available through the Internet. Web servers run specialized software like Apache or Microsoft Internet Information Services that allow them to host web pages. Many use third-party web hosting company.

What does a star topology look like?

Most widely deployed client/server network toplogy. Nodes connect to a switch in a pattern resembling a star. -The switch receives a signal from the sending node and retransmits it to the node on the network that needs to receive the signal. -Each network node picks up only the transmissions addressed to it. -The only drawback is if the switch fails, the network no longer works.

Why aren't P2P networks used more in business settings? Explain scalability.

P2P networks become difficult to administer when they are expanded beyond 10 users. Client server networks also have increased scalability. Scalability means that more users can be added easily without impacting the performance of other network nodes. You can install additional servers as workload increases without interrupting service for existing users.

E—mail server

Process and deliver incoming and outgoing e-mail

Network topology

The physical or logical arrangement of computers, transmission media (cable), and other network components. Physical topology: Refers to the layout of the real components of the network. Logical topology: Refers to the virtual connections between network nodes.Example: Bus, ring or star.

VPN (Virtual Private Network)

Used by intranets and extranets to keep information secure. VPNs use special security technologies and protocols that enhance security, enabling data to traverse the internet like on a private line VPN software installed.

Tunneling

VPN technology. Data packets are placed inside other data packets. The format of these data packets are encrypted and can be understood only by sending and receiving hardware, which is known as a tunnel interface.

What happens when signals collide?

When Nodes 1 and 2 collide, a node (#3) on the network detects the collision. Node #3 sends a special signal known as a jam signal to all network nodes, alerting them that a collision occurred. Original nodes #1 and #2 then stop transmitting and wait a random amount of time effort before retransmitting their data signals.

Extranet

a network configuration that allows selected outside organizations to access internal information systems