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Internetworking : Internet architecture and TCP/IP Protocol

TK3133Computer

Networking Technology

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Introduction

Internetworking :– Concept– Architecture– Protocol

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Introduction

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

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

Why different network ?– Network differ with different protocols– Install own network – Different network use different technology

Internetworking Scenario

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Internetworking

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Network differences

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Physical network connection using router 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

Example of two physical networks connected to a router that contain 2 different interfaces for each network connection

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Internet architecture

internetwork consist of various networks connected through router (Network can be LAN or WAN)

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Internet architecture

Router can have more that two interfaces

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Internet

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

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

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

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 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)

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)

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)

– 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

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

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

a) Transparent fragmentation

b) Nontransparent fragmentation

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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

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

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

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

Class A, B and C are primary class– Used to normal host addressing

Class D for multicasting, a form of limited broadcast

Class E specify for future use

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Dotted Decimal Notation

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

Example of assigning IP address to host

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Subnet

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

A network class B has 64 subnet

Needs additional information to differentiate between prefix and suffix called subnet mask

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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

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 – Host with IP will response

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Address Resolution Protocol (ARP)

McGraw-Hill ©The McGraw-Hill Companies, Inc., 2001

Figure 24-13ARP

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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)

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)

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) The IP protocol can be involved in two types of The IP protocol can be involved in two types of

communication: unicasting and multicasting. communication: unicasting and multicasting. IGMP is one of the necessary, but not sufficient, IGMP is one of the necessary, but not sufficient,

protocols that is involved in multicasting.protocols that is involved in multicasting. IGMP is a companion to the IP protocol.IGMP is a companion to the IP protocol.

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IGMP

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.