summer workshop on cyber security computer networks security (part 1) dr. hamed mohsenian -rad
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Summer Workshop on Cyber Security Computer Networks Security (Part 1) Dr. Hamed Mohsenian -Rad. University of California at Riverside and Texas Tech University July 14- 18, 2014 Supported by National Science Foundation. Overview of Computer Networks. mobile network. - PowerPoint PPT PresentationTRANSCRIPT
Summer Workshop on Cyber Security
Computer Networks Security (Part 1)
Dr. Hamed Mohsenian-Rad
University of California at Riverside and Texas Tech UniversityJuly 14- 18, 2014
Supported by National Science Foundation
2Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Internet: Millions of connected computing devices:
• End systems / Hosts (Running Net Apps)
• Communication Links (Wired or Wireless)
• Routers and Switches (Forward “Packets”)
mobile network
global ISP
regional ISP
home network
institutional network
Overview of Computer Networks
3Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Network of Networks• ISPs• Institutional Networks• Home Networks• Mobile Networks
Internet Protocols: • Control Sending & Receiving of Messages
• E.g.: TCP, IP, HTTP, 802.11
mobile network
global ISP
regional ISP
home network
institutional network
Overview of Computer Networks
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What is a Protocol?
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Human Protocol: • “What time is it?”, “I have a question.”, …
Network Protocols: • Machines instead of humans.
Protocols define format and order of messages sent and received among network entities, and actions taken on message transmission and message receipt.
5
What is a Protocol?
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocols define the interaction sequences over time:
Hi
Hi
Got thetime?2:00
TCP connectionresponse
Get http://www.awl.com/kurose-ross
<file>Time
TCP connectionrequest
6
Protocol Layers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Networks are complex with many “pieces”: • Hosts• Routers• Wired Links • Wireless Links• Applications• Protocols• Hardware• Software• …
7
Protocol Layers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Networks are complex with many “pieces”: • Hosts• Routers• Wired Links • Wireless Links• Applications• Protocols• Hardware• Software• …
Q: How can we organize the structure of networks?
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Example: Organization of Air Travel
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
A series of steps are taken at different “layers” :
ticket (purchase)
baggage (check)
gates (load)
runway takeoff
airplane routing
ticket (complain)
baggage (claim)
gates (unload)
runway landing
airplane routing
airplane routing
9
Example: Organization of Air Travel
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Each layer implements a “service”:
Via its own “internal-layer” actions.
ticket (purchase)
baggage (check)
gates (load)
runway (takeoff)
airplane routing
departureairport
arrivalairport
intermediate air-trafficcontrol centers
airplane routing airplane routing
ticket (complain)
baggage (claim
gates (unload)
runway (land)
airplane routing
ticket
baggage
gate
takeoff/landing
airplane routing
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Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application
Transport
Network
Link
Physical
There are five layers in Internet Protocol Stack with different functionalities and protocols.
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Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Application
Transport
Network
Link
Physical
12
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Application
Transport
Network
Link
Physical
13
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Application
Transport
Network
Link
Physical
14
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Application
Transport
Network
Link
Physical
15
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Application
Transport
Network
Link
PhysicalThey all use TCP Protocol for “reliable” data transmission. (Socket Programming) (Each socket has a port #)
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Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Application
Transport
Network
Link
Physical
17
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Application
Transport
Network
Link
Physical
18
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Application
Transport
Network
Link
Physical
19
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Link: Routing from source to destination Ethernet, IEEE 802.11 (WiFi)
Application
Transport
Network
Link
Physical
20
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Link: Routing from source to destination Ethernet, IEEE 802.11 (WiFi)
Application
Transport
Network
Link
Physical
21
Internet Protocol Stack
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application: Supporting network apps FTP, HTTP, SMTP, Skype
Transport: Process-to-process data transfer TCP, UDP
Network: Routing from source to destination IP, Routing Protocols
Link: Routing from source to destination Ethernet, IEEE 802.11 (WiFi)
Physical: Bit-by-bit transmission
Application
Transport
Network
Link
Physical
22
Packets
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Network communications are essentially 0-1 bit streams:
But we break down bit streams to small bit chunks = packets.
The packet at each layer:
Can have different names (frame, segment, etc.)
Can have different sizes
23
Packets
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Application
Transport
Network
Link
Physical
Application
Transport
Network
Link
Physical
Message
Segment
Datagram
Frame
24
Packet Headers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocol at each layer adds its own “headers” for “control data”.
Application
Transport
Network
Link
Physical
25
Packet Headers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocol at each layer adds its own “headers” for “control data”.
Application
Transport
Network
Link
Physical
Message
26
Packet Headers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocol at each layer adds its own “headers” for “control data”.
Application
Transport
Network
Link
Physical
Message HT
Used by TCP and UDP
Segment
27
Packet Headers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocol at each layer adds its own “headers” for “control data”.
Application
Transport
Network
Link
Physical
Message HT HN
Used by IP, Routing
Datagram
28
Packet Headers
Summer Workshop on Cyber Security July 14 - 18 , 2014 – Network Security, UCR & TTU
Protocol at each layer adds its own “headers” for “control data”.
Application
Transport
Network
Link
Physical
Message HT HN HL
Used by Ethernet, …
Frame