Transcript Document

TK3133
Computer
Networking
Technology
Internetworking :
Internet architecture
and TCP/IP Protocol
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Introduction
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Internetworking :
– Concept
– Architecture
– Protocol
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Introduction
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In the real world, computer is connected to various
technology of LAN and WAN
In reality, network is heterogeneous – various
network (and it is not homogeneous)
Contain millions of networks which connected to
high-speed backbone
Each systems should adapt to various technology
Introduce to internetworking concept
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Internetworking
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Internetworking is a schema for connecting various
network with different technology
 Use both hardware and software
 Additional hardware are placed between network
 Software is in the computer that is connected with
 Connected networking system is called internetwork /
internet
 Also called as virtual network
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Internetworking
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Why different network ?
– Network differ with different protocols
– Install own network
– Different network use different technology
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Internetworking Scenario
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Internetworking
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Network differences
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Physical network connection
using router
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Router is a component or hardware device which is
used to connect networking
Router has more interface on various networking
Router send and deliver packet between networks
Change the packet if necessary to fulfill the
standard of each network with different technology
(is also called as gateway)
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Router
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Example of two physical networks connected to a
router that contain 2 different interfaces for each
network connection
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Internet architecture
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internetwork consist of various networks
connected through router (Network can be
LAN or WAN)
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Internet architecture
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Router can have more that two
interfaces
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Internet
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The internet concept. (a) The illusion of a single network that TCP/IP software
provides to users and applications, and (b) the underlying physical structure in
which a computer attaches to one physical network, and routers interconnect
the networks
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Internet seen by TCP/IP
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Protocol for Internet
TCP/IP is the most popular
internetworking protocol
 The first internetworking protocol
 Maintain by ARPA and taken over by
NSF
 Independent to platform and
manufacturer
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TCP/IP layer
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OSI 7-layer model not include internetworking
Model TCP/IP layer model contain 5 layers
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TCP/IP layer and OSI model
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TCP/IP Layer
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Layer 5: Application
 Similar to layer 5,6 and 7 in OSI model
 Layer 4: Transport
 Similar to layer 4 in OSI model ; provide reliable
transmission of data
 Layer 3: Internet
 Define standard format packet sent through network
with different technology and provide mechanism for
packet transmission by router
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TCP/IP Layer
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Layer 2: Network interface
 Similar to layer 2 in OSI; define framework format
Layer 1: Physical
 Similar to layer 1 in OSI; define basic of network
hardware
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Host, Router and Protocol
Layer
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Host computer is any computer system connected to
internet and perform application
 TCP/IP allow the hosts at internet have direct
communication
 Both host and router needs TCP/IP stack
 Host normally has an interface and is not forwarding
packet
 Router forwards packet but does not need layer 4
and 5
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Network Layer
Internet Protocol (IP)
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How to manage network in network?
– Use network layer protocol called as
Internet Protocol (IP)
– Enable for a procedure running on a
computer sending data to application
procedure that running on other computer
at another distance network
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Internet Protocol (IP)
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IP responsible for providing best-effort
transmission for packet (or datagram)
 How is the communication in the Internet ?
– Transport layer takes data flow and divides them
into datagram
– Network layer send each datagram through
Internet. Division into smaller unit may happen
during this process.
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Internet Protocol(IP)
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– At the destination, datagram is re-gathered by
network layer to original datagram and is sent to
transport layer
Best-effort does not guarantee in managing datagram
overlapping problem, slow or not-sequence
transmission, lost and corrupted data
Service that offered by IP is without connection
IP define hardware-free packet format that can be
sent called Datagram IP
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Datagram IP
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IPv4 defines datagram at maximum 64Kb
 Head format datagram IP
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Head Protocol of IPv4
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Datagram IP Format
FIELD
Description
VERSION
Version number of datagram IP
IHLEN
What is the length of datagram IP head
TOS
Type of services offered
Total Length
What is the length of datagram
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IP Protocol
Field
Description
Identification
Unique identification to datagram
Fragment Offset
Offset for fragment
Time To Live
Counter to maximum number of datagram
longevity
Protocol
Give protocol to top layer
Checksum
Define genuine of head
Source/destination
address
Full address of source/destination node
Option
May be contain security option
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Fragmentation
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Each network technology define the maximum data
that can be sent in a packet. This limitation called
MTU (Maximum Transmission Unit).
When a router accept a datagram that bigger than
MTU, router would fragment datagram into smaller
fragment
Each fragment is sent to a destination that
responsible to match/reconnect the original datagram
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Fragmentation
Transparent fragmentation
b) Nontransparent fragmentation
a)
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Fragmentation
Fragmentation when the elementary data size is 1 byte.
(a) Original packet, containing 10 data bytes.
(b) Fragments after passing through a network with maximum packet
size of 8 payload bytes plus header.
(c) Fragments after passing through a size 5 gateway.
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Address issue
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Main aspect in virtual network is a standard address
format
 Cannot use hardware address because different
technology use different address format
 Address format should independence to any address
format of hardware address
 Sending Host place internet destination address in
packet/datagram
 Router check destination address and send packet to
destination
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TCP/IP address
Addressing in TCP/IP defined by
Internet Protocol (IP)
 Each host assigned to a 32-bit number
 Called IP address or Internet address
 Unique to throughout Internet
 Each datagram contain IP address of
source and destination
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IP address
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Each IP address divided into two categories :
network number (prefix) and host number
(suffix)
 Network number shows physical network in
which computer connected
 Host number shows unique number of
computer at network
 Address format enable routing to be efficient
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Define IP address
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From 32-bit, some bit assigned to prefix and
some to suffix
 Prefix bigger , suffix smaller - many network,
few host at network
 Prefix smaller, suffix bigger - few network,
many host at network
 Because there are various technology, should
allow smaller and bigger networks
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Address classification
Various address format to allow both
small and big prefix
 Each format called an address class
 A class is identified through the first four
bit
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Class Format of IP address
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IP address
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Using class IP
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Class A, B and C are primary class
– Used to normal host addressing
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Class D for multicasting, a form of limited
broadcast
 Class E specify for future use
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Dotted Decimal Notation
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IP number is binary number 32-bit.
 To make it easier dotted decimal notation is
used
 32-bit number defined as 4 section 8-bit in
decimal number and use dot to separate
section
 To identify class from decimal number, can
use address range
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Dotted Decimal Notation
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Dotted Decimal Notation
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Class Range from IP address
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Number of networks and hosts
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Example of class addressing
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Example of assigning IP address to host
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Subnet
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Able to divide the network into sub-network
 Example: a platform has one IP address class
B assigned to network but has two or more
physical network. Only local router know
about various subnet and how to send data to
it, other routers know only that there is just
one network.
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Subnet
A campus network with LAN for various
departments
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Subnet
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Needs additional information to differentiate
between prefix and suffix called subnet mask
A network class B has 64 subnet
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IPv6
128 bit address
 Head is more easier
 More service supports
 Security
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IPv6 Head
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Internet control protocols
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As addition to IP, Internet network layer has
several control protocol :
– Address Resolution Protocol (ARP)
– Reverse Address Resolution Protocol (RARP)
– Internet Control Message Protocol (ICMP)
– Internet Group Management Protocol (IGMP)
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Address Resolution Protocol (ARP)
Connection between host using IP
address, but connection at data link
layer using MAC address
 This protocol used for finding MAC
address for NIC that used by host with
certain IP
 Send request by broadcast
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– Host with IP will response
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Address Resolution Protocol (ARP)
Figure 24-13
McGraw-Hill
ARP
©The McGraw-Hill Companies, Inc., 2001
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Reverse ARP (RARP)
Normally used by diskless computer.
When it is booted from ROM, MAC
address is known and want to know its
IP address.
 It can only be used in the same
segment.
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Internet Control Message Protocol
(ICMP)
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Used for configuration and IP networking
(due to unreliability of IP)
 Can give feedback about network
problems
 Type of message
– Destination unreachable
– Time to live (TTL) exceeded
– Parameter problem (header unknown)
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Internet Control Message Protocol (ICMP)
– Redirection
– Response to request ( ping packet)
– Response to request with time feedback (ping
needs time info (timestamped)
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Use IP, so it can act by its own
– Example of instruction that used ICMP
• Ping and Traceroute
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Internet Control Message Protocol (ICMP)
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Internet Group Management
Protocol (IGMP)
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The IP protocol can be involved in two types of
communication: unicasting and multicasting.
 IGMP is one of the necessary, but not sufficient,
protocols that is involved in multicasting.
 IGMP is a companion to the IP protocol.
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IGMP
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There are two phases :
– Phase 1 : when a host become a member
of a multicast group, it send a IGMP
message to multicast group address to
declare its membership. Local multicast
router receives message and inform
member information to other multicast
router in internet
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IGMP
– Phase 2 : because the membership is
dynamic, multicast router periodically
should poll for host in local network to
certify whether any host is still active or
not. If not active, inform to other multicast
router.
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