IT263 Week 1 a Orientation and Introduction
Transcript of IT263 Week 1 a Orientation and Introduction
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
1/21
IT263-502 (Winter 2012)
Applied Networks and Security
Week 1-AOrientation/Introduction
Prof. Andrew S. Wang
DePaul University
1
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
2/21
Announcements
1. Sign in
2. Fill out the 1st Class Survey
3. Received my emails?
4. Syllabus on COL?
5. Week 1-A slides on COL?
2
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
3/21
Agenda
1. Course Orientation
2. OSI 7-layer Network Model
3. Demo of 4 OSI Layers Operations4. TCP/IP 4-layer Network Model
5. Student Intro.
3
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
4/21
1. Course Orientation
Syllabus on COL:
https://col.cdm.depaul.edu
4
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
5/21
2. OSI 7-Layer Network Model
OSI = Open Systems Interconnection To truly understand and learn computer network
operations data networking:
an open, generic network model
capturing most networking functionalities
used as a foundation for developing networking
systems/products
teaching/education/training tool
1984, OSI model published by ISO (International
Organization for Standardization)
5
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
6/21
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
7/21
3. Demo of 4 OSI Layers Operations
Web Browser (1):
Users perspective
7
Bob: Enter www.cnn.comLarry = CNN news
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
8/21
3. Demo of 4 OSI Layers Operations
Web Browser (2): HTTPs perspective
HTTP = HyperText Transfer Protocol
one Application Layer protocol (Layer 7)
8
Bob: Sends an HTTP (Layer-7) message to LarryLarry: Responds by sending two things (1) OK (2) home.htm
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
9/21
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
10/21
3. Demo of 4 OSI Layers Operations
Web Browser (4): IPs perspective (Layer 3)IP = Internet Protocol one Network Layer protocol
R1, R2, R3 = Routers (devices connecting Local Area Networks)
Destination IP address = 1.1.1.1 Source IP address = 2.2.2.2
Encapsulation: Top-down direction
PDU = Protocol Data Unit
Current-layer PDU = current-layer data + current-layer header
= upper-layer PDU + current-layer header 10
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
11/21
3. Demo of 4 OSI Layers Operations
Web Browser (5): PPPs perspective (Layer 2)PPP = Point-to-Point Protocol one Data-Link Layer protocol for WAN (Wide-
Area Network)
Ethernet (the)Data-Link Layer protocol for LAN (Local Area Network)
R2 changes Ethernet layer 2 header to PPP layer 2 header.
R1 changes PPP layer 2 header to Ethernet layer 2 header.
11
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
12/21
3. Demo of 4 OSI Layers Operations
Summary:
HTTP = a Layer 7 protocol
TCP = a Layer 4 protocol
IP = a Layer 3 protocol
PPP = a Layer 2 protocol
Ethernet = a Layer 2 protocol
Encapsulation = going from Layer 7 to Layer 1 (downward)
(the sender)
Decapsulation = going from Layer 1 to Layer 7 (upward)(the receiver)
In addition: Same-layer interaction on (one, two) computer(s)?
Adajcent-layer interaction on (one, two) computer(s)?
12
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
13/21
4. TCP/IP 4-layer Model
13
TCP/IP existed way before OSI 7-layer model.
TCP/IP is an actual model, OSI 7-layer is theoretical. TCP/IP model is also referred to as the DoD model.
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
14/21
5. Student Intro Career interest?
Bears, Bulls, Whitesox, Cubs, Blackhawks, Fire
(or: None of the above)
Travel experience (the most beautiful place)
Student clubs (poker club?) ROTC
14
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
15/21
Time for a checkpoint:
Are you ready?
15
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
16/21
Checkpoint 1
________ True or False.
The OSI 7-layer model is the most cost-effectivenetwork model that has ever been implemented so
far.
16
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
17/21
Checkpoint 2
HTTP is a protocol for which OSI layer? __________
a) Application layer
b) Presentation layer
c) Session layerd) Transport layer
e) Network layer
f) Datalink layer
g) Physical layer
17
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
18/21
Checkpoint 3
PPP is a protocol for which OSI layer? __________
a) Application layer
b) Presentation layer
c) Session layerd) Transport layer
e) Network layer
f) Datalink layer
g) Physical layer
18
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
19/21
Checkpoint 4
The most important reason for your PC to connect to anetwork is: __________
a) To connect to Internet
b) To do multitaskingc) To save cost
d) To be more efficient
e) To share resources with other PCs or servers on
the same network or on a different networkf) To be able to send email to and receive email
from other PCs on the same network
19
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
20/21
Checkpoint 5
The name of the network device that connects two(local area) networks is called _______ ?
20
-
8/3/2019 IT263 Week 1 a Orientation and Introduction
21/21
Checkpoint 6
What are the pros and cons for a wireless network interms of convenience, speed, cost, security?
21