internet protocol architecture chapter 2. the internet internet evolved from arpanet developed in...
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Internet Protocol Architecture
Chapter 2
The Internet
Internet evolved from ARPANETDeveloped in 1969 by the Advanced
Research Projects Agency (ARPA) of the U.S. DOD
First operational packet networkPacket network also applied to tactical radio
& satellite nets need for interoperability led to standardized TCP/IP protocols
Internetworking standards was proposed by Vint Cerf and Bob Kahn (TCP/IP)
Key Elements
Hosts: computers, mainframes, workstations, etc.
Ethernet Switch: Connecting hosts in a LAN (multiple segments)
Routers: Connecting LANs and WANS
Each segment can be a separate building
Cisco's Catalyst Switch
http://www.querycat.com/question/f3d88ef267ad2505f6e7cfe3061aaca3
Key Elements
ISP (Internet service provider) Regional ISP Backbone ISP
CPE (customer premises equipment): modems, DSL, cable modem, satellite
NAP (network access point): One of the major elements connecting ISPs
Last mile (or local loop): physical path (infrastructure) between the host and the ISP – coax. Copper, etc.
POP (point of present): ISP site with communication equipments
NSP (network service provide): The company that provides backbone services to ISPs
http://navigators.com/internet_architecture.html
Internet Architecture
Internet Architecture
Example ConfigurationAssume -Company C, located in San Francisco,
-Has 5 hosts-Connected to an ISP Y
-David located in NY -Connected to ISP Z-Uses DSL
- Company A runs the NAP in West coastAnd company B runs the NAP in East Coast
-Peer agreement
Show: POPsCPERegional ISP
http://www.vtc.com/products/TCP/IP-for-Windows-tutorials.htm
Example ConfigurationAssume -Company C, located in San Francisco,
-Has 5 hosts-Connected to an ISP Y
-David located in NY -Connected to ISP Z-Uses DSL
- Company A runs the NAP in West coastAnd company B runs the NAP in East Coast
-Peer agreement Show: POPsCPERegional ISP
Network Protocols
Protocols define format, order of messages sent and received among network entities, and actions taken on message transmission
Set of rules or conventions that allow peer layers to communicate
Key features Syntax (format of the data) Semantics (Control information, error handling) Timing (sequencing and synchronization)
How Does a Protocol Work?
A human protocol and a computer network protocol:
Hi
Hi
Got thetime?
2:00
TCP connection request
TCP connectionresponseGet http://www.awl.com/kurose-ross
<file>time
Open Systems Interconnection - OSI
Developed by the International Organization for Standardization (ISO)
Has seven layers Is a theoretical
system delivered too late!
TCP/IP is the de facto standard
Peer layers communicate with one another
Open Systems Interconnection - OSI
TCP/IP Protocol Architecture
Developed by US Defense Advanced Research Project Agency (DARPA)
For ARPANET packet switched network
Used by the global Internet
Protocol suite comprises a large collection of standardized protocols
TCP/IP Layers
Application layer Host-to-host, or
transport layer Internet layer Network access layer Physical layer
Physical Layer Protocols Responsible for transporting the
information encapsulating information and
getting it ready for transportation Deals with physical interfaces,
electrical parameters, pin outs, number of twists per foot, cable gauge, data rate, signal integrity, etc.
Examples: RS-232, V.35, RJ-48, DS3, OC-n, High Speed Serial Interface
Physical Layer Protocols - Examples RS-233
Interfacing computer to modem Supports speeds up to 9.6 Kbps 25-pin or 9-pin interface
V.35 Serial interface between the
terminal and the digital communication equipment (T1)
Supports speeds above 19.2 Kbps RJ-48
Physical interface for T1 and E1 Defined by G.703 standards
DS3 Uses coaxial cable Supports 45 Mbps
OC-n Fiber optic interface n can be 1,3,12,etc. Multimode or single mode
High speed Serial Interface Supports 42 Mbps Interfacing ATM switches
Data Link Layer Protocols Frame and format information according to some
standards Two basic categories
Connection oriented Technology Establishing pre-defined virtual path upon request Many different virtual paths can reside on a physical link (like a
highway system) Example: ATM and Frame Relay Protocols
Connectionless Technology Only source and destination addresses are defined No pre-defined path exists between devices The actual routing path can be different depending on the network
status Example: High-level Data Link Control (HDLC)
Network Protocol Layers Transporting individual packets of information
through the network end-to-end Can route packets according to actual device
address or network topology (connectionless) Routing is done according to the network
manager or by a dynamic routing protocol Without Network layer all routings will be point-
to-point Examples:
Internet Protocol (IP) used on Internet Packet-based; Connectionless
IPX developed by Novel used in LAN Packet-based; Connectionless
Transport Protocol Layers Interfacing the upper layers to lower layers Formats applications into segments Examples: TCP and UDP Offers end-to-end flow TCP
Provides reliable delivery of data Keeps track of packet order
UDP User Datagram Protocol Does not guarantee delivery Offers faster data delivery
Application Layer
provide support for user applications need a separate module for each type of
application
TCP/IP Applications
Simple Mail Transfer Protocol (SMTP) Provides basic electronic mail Only sends (forwards) mail Uses TCP
File Transfer Protocol (FTP) Used to send files between systems – file transfer Uses TCP connect to check the ID and PW Establishes another TCP connection for data transfer
Telnet Provides remote login Implemented in two modules: User and Server
User Telnet: Interacts with terminal I/O module Makes the remote terminal appear as local terminal
TCP/IP Applications
Operation of TCP and IP
Addressing Requirements Two levels of addressing
required Each host on a subnet
needs a unique global network address called IP address
each application on a (multi-tasking) host needs a unique address within the host known as a port
Subnets: attached devicesDefined by the networkAccess Layer
Operation of TCP/IPProcess at A hands the message to TCP layer: Send the message to host B port 2
TCP hands the message to IP – destination will be Host B
IP hands it to network Layer -> next hop is router J
Conditions The signal format For the physical path
Operation of TCP/IP
Data from the applications software
Header contains: Destination port, sequence numberChecksum
Header contains: Destination of the host address
Header contains: Destination subnet address – which attached deviceFacility request: e.g., priority
Transmission Control Protocol (TCP) Standard transport layer for Internet is (TCP) Provides a reliable connection for transfer of
data between applications A TCP segment is the basic protocol unit
Logical connection between peer layers TCP provides host-to-host connection (port-to-port)
TCP tracks segments between entities for duration of each connection Segment flow
TCP Header
User Datagram Protocol(UDP) An alternative to TCP No guaranteed delivery No preservation of sequence No protection against duplication Minimum overhead Adds port addressing to IP
That is why we need it!
UDP Header
IP Protocol IPv4
Addresses are 32 bits wide Its header is 20 bytes at minimum Uses doted-decimal notation (e.g. 43.23.43.56)
IPv6 Provides larger address domain; addresses are 128
bits wide Multiple separate headers are supported Handles audio and video; providing high quality paths Supports unicast, multicast, anycast
IP Header
IPv6 Header
OSI - review Open Systems Interconnection developed by the International
Organization for Standardization (ISO)
has seven layers is a theoretical system
delivered too late! TCP/IP is the de facto
standard
Standardized Protocol Architectures
Each layer must interacts with threeOther layers
Protocols define which services are Provided
Providing services to N+1Multiple services: Each service has an address: Called Service access Point
Service Primitives and Parameters
Adjacent layers provide services to one another:
Primitives to specify function performed
Parameters to pass data and control info
N N-1 N-1 N
Elastic and Inelastic Traffic Elastic traffic
can adjust to delay & throughput changes over a wide range
eg. traditional “data” style TCP/IP traffic Inelastic traffic
does not adapt to such changeseg. “real-time” voice & video trafficneed minimum delay requirements
General Traffic Characteristics
Throughput Amount of data carried over time
Delay Time it take to deliver data between hosts
Delay Variation Variation in the time when delivering the data
Packet Loss Packets not made it to the destination
Media Types
Text, Audio, Graphic, and Video Different technologies are required to support
various media types Examples of multimedia technologies
Compression: JPG for images, MPG for video Transmission and networking technologies Protocols: RTP (real-time transport protocol) Quality of service (QoS) – providing different levels of
services to different applications
Watch this: http://www.vtc.com/products/TCP/IP-for-Windows-tuto
rials.htm
TCP/IP Applet http://www.kom.e-technik.tu-darmstadt.de/projects/ite
ach/itbeankit/Applets/TCP/tcp.html
Simple TCP/IP Lab http://www.windowsnetworking.com/articles_tutorials/t
sttcpip.html?printversion
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