Chapter 5 Data Communication and Internet Technology

prunelimitNetworking and Communications

Oct 23, 2013 (3 years and 9 months ago)

72 views

Chapter 5

Data Communication

And

Internet Technology

Purpose


Understand the fundamental networking
concepts

Agenda


Network Concepts


Communication Protocol


TCP/IP
-
OSI Architecture


Network Types


LAN


WAN


Public Switched Data Network


Virtual Private Network


Network Comparison


Internet


Domain Name System


IP Addressing Schemes


Security


Discussion and Case Study

Network Concepts


A collection of computers that
communicate with one another over
transmission lines


Types


Local area networks (LANs): connects
computers in a single geographic location


Wide area networks (WANs): connects
computers at different geographic sites


Internet: a network of networks

Communication Protocol


Protocol: a standard means for
coordinating an activity between two or
more entities


Communications protocol: a means for
coordinating activity between two or more
communicating computers


The communication protocol is broken into
levels of layers


Two machines must agree upon and follow
the protocol for exchanging the message

TCP/IP
-
ISO Architecture
-

I


International Organization for
Standardization (ISO): Reference Model
for Open Systems Interconnection (OSI)


Internet Engineering Task Force (IETF):
Transmission Control Program/Internet
Protocol (TCP/IP)


TCP/IP
-
ISO architecture: five layers


TCP/IP
-
ISO Architecture
-

II


Layer 5 (Application): communication rules
between two applications


Simple Mail Transfer Protocol (SMTP) for
email


Hypertext Transfer Protocol (HTTP) for
processing Web page (sites and users)


File Transfer Protocol (FTP) for copying file
between computers

TCP/IP
-
ISO Architecture
-

III


Layer 4 (Transport): communication rules
between two host computers


Transmission Control Program (TCP)


Sending functions: break data into segments,
add To and From address, and


Receiving functions: provide reliability by
sending acknowledgement, and translate the
format, assemble segments into data

TCP/IP
-
ISO Architecture
-

IV


Layer 3 (Internet): communication rules of
routing packets across the Internet


Internet Protocol (IP)


Functions: package each segment into a
packet, place IP data in in the packet, add
To/From data

TCP/IP
-
ISO Architecture
-

V


Layer 2 (Data Link): communication rule
for transmitting data within a single
network


Functions: package packets into frames


Layer 1 (Physical): communication rule
between adjacent device connected by a
transmission medium

Terminology


Architecture: an arrangement of protocol layers
with their associated tasks


Protocol: set of rule to accomplish the tasks


Program: software implementing the protocol


Web: sub set of Internet with users and sites to
process protocol


Internet: communication structure


Browser: a program implementing the HTTP of
the TCP/IP
-
OSI architecture (Netscape and
Microsoft Internet Explorer)

TCP/IP
-
OSI Application Example

Network Types


LAN: local area network


WAN: wide area network

LAN
-

I


A group of computers connected together
on a single company site and operated by
the company


Equipments


Network interface card (NIC) or onboard NIC:
an unique identifier named MAC (media
access control) address


Unshielded twisted pair (UTP) cable with RJ
-
45 connecter


Optical fiber cable with ST and SC connectors

LAN
-

II


IEEE (Institute for Electrical and Electronics
Engineers)


Protocol: IEEE 802.3 or Ethernet


Hardware characteristics (which wire carries which
signals)


Package and process message over LAN


Operate on Layer 1 and 2


10/100/1000 Ethernet (Mbps)


Bits for communications speeds and bytes for
memory sizes

Local Area Network

NIC Interface Card

Unshielded Twisted Pair (UTP) Cable

Optical Fiber Cable

LAN
-

III


Wireless LAN


Wireless NIC (WNIC)


IEEE 802.11g protocol to connect to an
access point (AP) and IEEE 802.3

Wireless Access Standards

Wireless LAN

WAN


Connects computers located at physically
separated sites


Internet service provider (ISP)


Provide customer a legitimate Internet address.


Serve as the gateway to the Internet


Communicate between sending computer and
Internet


Connecting computer and ISP


Telephone line


DSL (digital subscriber line)


Cable TV line

WAN
-

Equipment


Modem


Convert data between digital and analog


Narrowband with speed less than 56 kbps and Broadband with speed
over 256 kbps


Modem types


Dial
-
Up modem


Narrowband


Point
-
to
-
Point Protocol (PPP)


DSL modem


Permanent connection and one more line for telephone conversation


Asymmetric digital subscriber line (ADSL) for home and small business with
slow upload speed with 256 kbps and faster download speed ranging from
256 to 768 kbps


Symmetric digital subscriber line (SDSL) for advanced users and larger
business with 1.544 Mbps performance level guarantees


Cable modem


Permanent connection and one more line for TV


10 Mbps download speed and 256 kbps upload speed

Analog vs. Digital Signals

Personal Computer (PC) Internet Access

WAN
-

Equipment


Access devices


Switch (Layer 2)


Router (Layer 3)


Lease lines from telecommunication
company


T1 line with 1.544 Mbps speed


T3 line with 44.763 Mbps speed


Optical fiber cable
-
768 with 40 Gbps


Point
-
to
-
Point Protocol (PPP)

Transmission Line Types, Uses, and Speeds

WAN


Public Switched Data Network


Public switched data network (PSDN)


Developed and maintained by a vendor for selling time to
other company


Shown as a cloud in the map or diagram


User must have a leased line connecting to PSDN as
point of presence (POP)


PSDN types


Frame Relay with 56 kbps to 40 Mbps: slower and cost less but
simple and easy to support


Asynchronous transfer mode (ATM) with 1 to 156 Mbps: faster
and cost more but transmitting data and voice


Ethernet with 10 to 40 Gpbs

Wide Area Network Using PSDN

WAN


Virtual Private Network


Virtual private network (VPN): a private
internet as a private point
-
to
-
point
connection


Tunnel: a virtual, private pathway over a
public or shared network from the VPN
client to the VPN server


Encrypted message


Remote access

Remote Access Using VPN

Wide Area Network Using VPN

Network Comparison


Setup costs


Equipment: lines, switches, routers, and access devices


Labor


Operational costs


Lease fees for line and equipment


ISP charges


Training


Maintenance: problem diagnosis, repair, and updating


Performance


Speed: line and equipment


Latency: transmission delay due to congestion


Availability: service outages


Loss rate: transmission problem


Transparency


Performance guarantee: availability, error rate, speed, etc.


Growth potential


Contract commitment period


Management time


Financial risk


Technical risk

Summary of LAN and WAN Networks

Internet


Network address


Physical or MAC address in Layer 2 program: permanent and
unique


Logical or IP address in Layers 3, 4, and 5: not permanent, such
as 192.168.2.28


Public IP address used on the Internet to major institutions in
blocks assigned by Internet Corporation for Assigned Names
and Numbers (ICANN)


Private IP address used within private networks and internets


DHCP server has Dynamic Host Configuration Protocol
(DHCP) to assign a temporary IP address for accessing
the Internet


Network Address Translation (NAT): The process of
changing public IP addresses into private IP addresses,
and the reverse

Domain Name System


Convert user
-
friendly name into their IP address


domain name: any registered, valid name with ICANN


resolving the domain name: the process of changing a
name into its IP address


ICANN has 13 computer as root servers for maintaining a list of
IP addresses of servers to resolve each type of TLD in the world


Top
-
level domain (TLD)


Non
-
U.S. is the two letter abbreviation for the country


U.S. is the type of organization


Uniform resource locator (URL): document’s address on
the Web


Domain name resolvers store the correspondence of
domain names and IP address

IP Addressing Schemes


IPv4 and


IPv4


32 bits divided into four groups of 8 bits, and a
decimal number represents each group


63.224.57.59


The largest decimal number between the period is
255 (0


255)


IPv6


128 bits due to the growth of the Internet


Currently both IPv4 and IPv6 are used on the Internet

Security


Encryption algorithms: DES, 3DES, AES


Key


Symmetric encryption


Asymmetric encryption: public key and private key


HTTPS


Secure Socket Layer (SSL) and Transport Layer
Security (TLS)


Public key, private key and symmetric encryption

Summary


TCP/IP
-
OSI five layers


Application layer


Transport layer


Internet layer


Data link layer


Physical layer


Public switched data network (PSDN)


Dynamic Host Configuration Protocol (DHCP) to
assign a temporary IP address for accessing the
Internet


Domain name


Discussion


Problem solving (121a
-
b)


What are the new opportunities for the business generated by the Internet?


What are the new threats for the business generated by the Internet?


Opposing forces (129a
-
b)


State your opinions related to the negative impact on the society when
everyone is connect through the Internet.


Security (133a
-
b)


State the impacts on the society and business from the government
having an decryption method to decode everything over the Internet.


Ethics (141a
-
b)


State the impacts from the employee’s private usage of company’s
computer facility.


Reflections (143a
-
b)


How should you react properly from not getting lost from this Internet age?

Case Study


Case 5
-
1 (148
-
149) Network Services:
questions 1, 3, 4, 5, 6, 9, and 10

Points to Remember


Network Concepts


Communication Protocol


TCP/IP
-
OSI Architecture


Network Types


LAN


WAN


Public Switched Data Network


Virtual Private Network


Network Comparison


Internet


Domain Name System


IP Addressing Schemes


Security


Discussion and Case Study