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Experiencing M I S

Tenth Edition

Chapter Extension 9

Network and Cloud Technology

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Study Questions

C E 9.1 What is a computer network?

C E 9.2 What are the components of a L A N?

C E 9.3 How does the Internet work?

C E 9.4 How do Web servers support the cloud?

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Types of Networks

C E 9.1 What is a computer network?

Figure C E 9.1 Basic Network Types

Type	Characteristic
Personal area network (P A N)	Devices connected around a single person
Local area network (L A N)	Computers connected at a single physical site
Wide area network (W A N)	Computers connected between two or more separate sites
The Internet and internets	Networks of networks

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Typical Small Office/Home Office (SOHO) LAN

C E 9.2 What are the components of a L A N?

Figure C E 9.2 Typical Small Office/Home Office

Most personal computers today support 10/100/1000 Ethernet. A LAN is a group of computers connected together on a single site.

Wired network devices communicate using the IEEE 802.3 protocol for LAN connections. This protocol standard, also called the Ethernet, specifies hardware characteristics, such as which wire carries which signals. It also describes how messages are to be packaged and processed for wired transmission over the LAN.

Long Description:

The four basic network types and their characteristics are as follows:

• Personal area network (PAN): Devices connected around a single person.

• Local area network (LAN): Computers connected at a single physical site.

• Wide area network (WAN): Computers connected between two or more separated sites.

• The Internet and internets: Networks of networks.

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Abbreviations Used for Communications and Computer Memory Speeds

C E 9.2 What are the components of a L A N?

Communications equipment,
K(ilo) = 1,000, not 1,024 (as for memory);
M(ega) = 1,000,000, not 1,024 × 1,024;
G(iga) = 1,000,000,000, not 1,024 × 1,024 × 1,024.

100 M b p s =100,000,000 bits per second.

Communications speeds expressed in bits, memory sizes in bytes.

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L A N Protocol

C E 9.2 What are the components of a L A N?

I E E E 802.3

Wired LAN
10/100/1000 Mbps

Ethernet

I E E E 802.11

Wireless LAN
802.11a c
Speeds up to 1.3 G b p s

Bluetooth

Transmits data short distances.
Connect computer, keyboard, mouse, printer, smartphones, smartwatches, automobiles, sports equipment, clothing.

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Connecting Your L A N to the Internet

CE 9.2 What are the components of a L A N?

Important I S P functions:

Provide legitimate Internet address.
Provide gateway to Internet.
Pay access fees and other charges to telecoms.

WAN wireless average performance 20 M b p s.
Typical wireless LAN 200 M b p s.

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Alternative Ways of Connecting to the Internet

C E 9.2 What are the components of a L A N?

Figure C E 9.3 Office (SOHO) LAN

Long Description:

The details are as follows:

Type: Local area network

• Topology: Local area network.

• Transmission line: UTP or optical fiber.

• Transmission speed: Common: 10/100/1000 Mbps Possible: 1 Gbps.

• Equipment used: Switch NIC UTP or optical.

• Protocol commonly used: IEEE 802.3 (Ethernet).

• Remarks: Switches connect devices, multiple switches on all but small LANs.

• Topology: Local area network with wireless.

• Transmission line: UTP or optical for nonwireless connections.

• Transmission speed: Up to 1.3 Gbps

• .Equipment used: Wireless access point Wireless NIC.

• Protocol commonly used: IEEE 802.11ac, (802.11ax becoming common).

• Remarks: Access point transforms wired LAN (802.3) to wireless LAN (802.11).

Type: Connections to the Internet

• Topology: DSL modem to ISP.

• Transmission line: DSL telephone.

• Transmission speed: Personal: Upstream to 1 Mbps, downstream to 40 Mbps (max 10 likely in most areas).

• Equipment used: DSL modem DSL-capable telephone line.

• Protocol commonly used: DSL.

• Remarks: Can have computer and phone use simultaneously. Always connected.

• Topology: Cable modem to ISP.

• Transmission line: Cable TV lines to optical cable.

• Transmission speed: Upstream to 1 Mbps Downstream 20 Mbps to 100 Mbps

• Equipment used: Cable modem Cable TV cable.

• Protocol commonly used: Cable.

• Remarks: Capacity is shared with other sites; performance varies depending on others’ use.

• Topology: WAN wireless.

• Transmission line: Wireless connection to WAN.

• Transmission speed: 500 Kbps to 1.7 Mbps.

• Equipment used: Wireless WAN modem.

• Protocol commonly used: One of several wireless standards.

• Remarks: Sophisticated protocols enables several devices to use the same wireless frequency.

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Postal System vs The Internet (1 of 2)

C E 9.3 How does the Internet work?

Figure C E 9.4 Comparison of the Postal System and the Internet

Steps to Send Package	Postal System	Internet Equivalent
1. Assemble package	Package	Packet
2. Put name on package	Person’s name (e.g., BigBank Inc. or Jane Smith)	Domain name (e.g., www.BigBank.com)
3. Look up address	Phone book	D N S
4. Put address on package	Mailing address (e.g., 123 Park Ave, New York, N Y, 10172)	I P address (e.g., 10.84.8.154)
5. Put registered mail sticker on package	Registered mail	T C P
6. Ship package	Airlines (e.g., Delta Air Lines, Inc.) Airports (e.g., Seattle-Tacoma International Airport)	Carriers (e.g., Sprint Corp.) Routers

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Postal System vs The Internet (2 of 2)

C E 9.3 How does the Internet work?

I P v 4

E.g.,137.190.8.10
Dotted decimal notation
Only about 4 billion addresses (not enough)

I P v 6

E.g., 0:0:0:0:0:f f f f:8 9 b e:8 0 a
Hexadecimal notation
340 undecillion addresses

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Domain Name System (D N S)

C E 9.3 How does the Internet work?

Domain name

Unique name affiliated with a public I P address.
Dynamic affiliation of domain names with I P addresses.
Multiple domain names for same I P address.

U R L (Uniform Resource Locator)

Internet address protocol, such as h t t p:// or f t p://.

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Private Versus Public I P Addresses

C E 9.3 How does the Internet work?

Public I P addresses

Identifies a unique device on Internet.
Assigned by I C A N N (Internet Corporation for Assigned Names and Numbers.)

Private I P addresses

Identifies a device on a private network, usually a LAN.
Assignment LAN controlled.

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I P Addressing: Major Benefits

C E 9.3 How does the Internet work?

Public I P addresses conserved

One public I P address per LAN.

Using private I P addresses

Eliminates registering public I P address with I C A N N-approved agencies.
Protects against direct attack.

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Domain Registry Company

C E 9.2 What are the components of a L A N?

Figure C E 9.5 Go Daddy Screenshot

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Packets & Carriers

C E 9.3 How does the Internet work?

Messages, broken into packets.
T C P guarantees delivery of packets.
Packets move across Internet, passing through networks owned by telecom carriers.
Peering agreements—Carriers freely exchange traffic amongst themselves without paying access fees.

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The Cloud Resides in the Internet

C E 9.3 How does the Internet work?

Figure C E 9.6 Using the Internet to Request a Web Page

Using Internet for Hotel Reservation

Assume you send a message to a server in New Zealand hotel. Message is too big to travel in one piece, so it’s broken into packets and each packet passes along from WAN to WAN until it reaches destination. Once all packets arrive, message reconstructed, delivered to server for processing. All accomplished by computers and data communications devices that most likely have not interacted before.
Hop is movement from one network to another.

Long Description:

The diagram shows the Internet at the center comprising four networks, network 1, network 2, network 3, and network 4, interconnected to each other. Network 1 is interconnected to an “internet service provider” which is further interconnected to “Your LAN,” Your LAN is also interconnected to “You in Seattle.” Network 4 is further interconnected to another “internet service provider” which is further interconnected to “Big Bank’s LAN.” Big Bank’s LAN is interconnected to a “Friend at Big Bank.”

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Net Neutrality

C E 9.3 How does the Internet work?

Net neutrality principle

All data treated equally.
Carriers should not be allowed to:

Decide which sites load quickly
Decide which apps are allowed on a network
Decide which content is acceptable

Problem: some people use more bandwidth than others.

Netflix, for example, accounts for more than 40 percent of all Internet traffic in North America during evening hours

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Processing on a Web Server

C E 9.4 How do Web servers support the cloud?

What happens when you visit a Web site and order something, and pay for it?

Figure C E 9.7 Sample of Commerce Server Pages; Product Offer Pages

Source: Courtesy of Zulily Inc. Used by permission.

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Three-Tier Architecture

C E 9.4 How do Web servers support the cloud?

Figure C E 9.8 Three-Tier Architecture

Almost all e-commerce applications use a three-tier architecture.

User tier consists of computers, phones, other devices with browsers that request and process Web pages.
Server tier consists of computers running Web servers and application programs.
Database tier consists of computers running a DBMS that processes SQL requests to retrieve and store data.

Commerce server — application program that runs on server-tier computer. Receives requests from users via Web server, takes some action, and returns a response to users. Typical commerce server functions are to obtain product data from a database, manage items in a shopping cart, and coordinate checkout process. Almost all e-commerce applications use a three-tier architecture.

User tier consists of computers, phones, other devices with browsers that request and process Web pages.
Server tier consists of computers running Web servers and application programs.
Database tier consists of computers running a DBMS that processes SQL requests to retrieve and store data.
Commerce server — application program that runs on server-tier computer. Receives requests from users via Web server, takes some action, and returns a response to users. Typical commerce server functions are to obtain product data from a database, manage items in a shopping cart, and coordinate checkout process.

Long Description:

The diagram shows “User Computers (User Tier)” with multiple layers of “web browsers” on the left. The “Web Server Computers (Server Tier)” appears at the center with multiple layers of server tiers, each made up of “commerce server application,” “other applications,” and “webserver (apache, IIS).” The commerce server application and other applications are interconnected to the webserver (apache, IIS). The web server (Apache, IIS) is interconnected to web browsers in the user computer through HTML via HTTP. The “DBMS Computer (Database Tier)” appears on the right with DBMS and DB interconnected to each other. DBMS is also interconnected to the commerce server application and other applications utilizing “Instructions and Data.”

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Watch the Three Tiers in Action! Sample of Commerce Server Page

C E 9.4 How do Web servers support the cloud?

Commerce server requests shoe data from D B M S.
D B M S reads from database, returns data to commerce server.
Commerce server formats Web page with data and sends html version of page to user’s computer.
Customer places items in shopping cart.
Customer checks out, commerce server program processes payment, schedules inventory processing, arranges shipping, email receipt to customer.

Figure C E 9.9 Product Page

Source: Courtesy of Zulily Inc. Used by permission.

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S O A Analogy: Approval Request Interactions Among Three Departments

C E 9.4 How do Web servers support the cloud?

Figure C E 9.10 Approval Request Interactions Among Three Departments

CheckCustomerCredit
ApproveCustomerCredit

VerifyInventoryAmount
AllocateInventory
ReleaseAllocatedInventory

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Using S O A Principles, Each Department Defines Its Own Services:

CE 9.4 How do Web servers support the cloud?

Credit Department

CheckCustomerCredit
ApproveCustomerCredit

Inventory Department

VerifyInventoryAmount
AllocateInventory
ReleaseAllocatedInventory

Each department formally states data to receive with request and data promised to return in response.
Every interaction done exactly same way.

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Using S O A Principles: Encapsulation

CE 9.4 How do Web servers support the cloud?

No department needs to know who works in another department, or how department accomplishes work.
Each department free to change personnel task assignments, change processes for performing services.
Best Bikes could dynamically create 1,000 Inventory Departments and Sales Department with no need to change anything it does.

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S O A Principles Applied to Three-Tier Architecture

C E 9.4 How do Web servers support the cloud?

Services

ObtainPartData
ObtainPartImages
ObtainPartQuantityOnHand
OrderPart

JavaScript written to invoke these services correctly.

Figure C E 9.11 S O A Principles Applied to Three-Tier Architecture

Commerce server application formally defines services browsers can request, data they must provide with the request, and data each will receive in response to request.
Organization must agree on standard ways of formatting and processing service requests and data.

Long Description:

The diagram shows “Load Balancer” interconnected to five browsers. A leftward arrow marked toward the browsers reads, “Html with Java Script that correctly requests service and processes responses.” The load balancer is interconnected to multiple 1,3,100,1000, etcetera web servers (commerce web server: webserver). A text reads, “Commerce server service requests rightward arrow and responses leftward arrow.” A DB load balancer is further interconnected to the commerce web servers. A text reads, “Database server service requests rightward arrow and responses leftward arrow.” The diagram further shows three database servers as 1, 3, and 50, each having a DBMSS interconnected to a DB.

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Protocols Supporting Web Services

C E 9.4 How do Web servers support the cloud?

Figure C E 9.12 Protocols That Support Web Services

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W S D L, S O A P, X M L, and J S O N

C E 9.4 How do Web servers support the cloud?

Standards	Definition
W S D L (Web Services Description Language)	Standard for describing services, inputs, outputs, other data supported by a Web service. Documents coded machine readable and used by developer tools for creating programs to access the service.
SOAP (No longer an acronym)	Protocol for requesting Web services and for sending responses to Web service requests.
X M L (eXtensible Markup Language)	A markup language used for transmitting documents. Contains much metadata that can be used to validate the format and completeness of a document but includes considerable overhead (see Figure CE9-13a).
J SON (JavaScript Object Notation)	A markup language used for transmitting documents. Contains little metadata and is preferred for transmitting volumes of data between servers and browsers. While notation is the format of JavaScript objects, J SON documents can be processed by any language (see Figure CE9-13b).

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Example X M L and J S O N Documents (1 of 2)

C E 9.4 How do Web servers support the cloud?

Figure C E 9.13a Example X M L Document

XML and JSON are ways of marking up documents so that both the service requestor and the service provider know what data they’re processing. This slide shows a simple example of both. XML documents contain as much metadata as they do application data. These metadata are used to ensure the document is complete and properly formatted.
XML is used when relatively few messages are being transmitted and when ensuring a complete and correct document is crucial. Both WSDLs and SOAP messages are coded in XML.
JSON uses the notation for JavaScript objects to format data. It has much less metadata and is preferred for the transmission of voluminous application data. Web servers use JSON as their primary way of sending application data to browsers.

Long Description:

The screenshot showing the program code for the XML document is as follows:

Line 1: Open parenthesis person close parenthesis

Line 2: indented, open parenthesis firstname close parenthesis Kelly open parenthesis forward-slash firstname close parenthesis

Line 3: indented, open parenthesis Lastname close parenthesis Summers open parenthesis forward-slash Lastname close parenthesis

Line 4: indented, open parenthesis dob close parenthesis 12 forward slash 28 forward slash 1985 open parenthesis forward-slash dob close parenthesis

Line 5: indented, open parenthesis address close parenthesis

Line 6: indented twice, open parenthesis streetaddress close parenthesis 309 Elm Avenue open parenthesis forward-slash streetaddress close parenthesis

Line 7: indented twice, open parenthesis city close parenthesis San Diego open parenthesis forward-slash city close parenthesis

Line 8: indented twice, open parenthesis state close parenthesis CA open parenthesis forward-slash state close parenthesis

Line 9: indented twice, open parenthesis postalcode close parenthesis 98225 open parentheses forward-slash postalCode close parenthesis

Line 10: indented, open parenthesis forward-slash address close parenthesis

Line 11: indented, open parenthesis phonenumbers close parenthesis

Line 12: indented twice, open parenthesis phone number type equals “home” close parenthesis 685 555 – 1234 open parenthesis forward-slash phonenumber close parenthesis

Line 13: indented twice, open parenthesis phone number type equals “cell” close parenthesis 685 555 – 5678 open parenthesis forward-slash phonenumber close parenthesis

Line 14: indented, open parenthesis forward-slash phonenumbers close parenthesis

Line 15: indented, open parenthesis forward-slash person close parenthesis

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Example X M L and J S O N Documents (2 of 2)

C E 9.4 How do Web servers support the cloud?

Figure C E 9.13b Example J S O N Document

XML and JSON are ways of marking up documents so that both the service requestor and the service provider know what data they’re processing. This slide shows a simple example of both. XML documents contain as much metadata as they do application data. These metadata are used to ensure the document is complete and properly formatted.
XML is used when relatively few messages are being transmitted and when ensuring a complete and correct document is crucial. Both WSDLs and SOAP messages are coded in XML.
JSON uses the notation for JavaScript objects to format data. It has much less metadata and is preferred for the transmission of voluminous application data. Web servers use JSON as their primary way of sending application data to browsers.

Long Description:

The program output for the JSON document reads as follows:

Line 1: open brace

Line 2: indented, “firstName” colon “Kelly” comma

Line 3: indented, “last name” colon “Summers” comma

Line 4: indented, “dob” colon “12 forward slash 28 forward slash 1985” comma

Line 5: indented, “address” colon open brace

Line 6: indented twice, “streetAddress” colon “309 Elm Avenue” comma

Line 7: indented twice, “city” colon “San Diego” comma

Line 8: indented twice, “state” colon “CA” comma

Line 9: indented twice, “postalCode” colon “98225” comma

Line 10: close brace comma

Line 11: “phone number” colon open bracket

Line 12: indented, open brace

Line 13: indented twice, “type” colon “home” comma

Line 14: indented twice, “number” colon “685 5555-1234”

Line 14: indented, close brace comma

Line 15: indented, open brace

Line 16: indented twice, “type” colon “cell” comma

Line 17: indented twice, “number” colon “685 555 – 5678” comma

Line 18: indented twice, close brace

Line 19: indented, close bracket

Line 20: close brace

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Active Review

C E 9.1 What is a computer network?

C E 9.2 What are the components of a L A N?

C E 9.3 How does the Internet work?

C E 9.4 How do Web servers support the cloud?

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