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Network Layer Protocols: ARP, IPv4, ICMP, IPv6 and ICMPv6

20.1 ARP20.2 IP20.3 ICMP20.4 IPv6

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Figure 20.1 Protocols at network layer

Address Resolution ProtocolFind MAC addressof next-hop host

Reversed ARPObsolete

Internet Control Message Protocol Provides error control and messaging capabilities in unicasting

Internet Group Management ProtocolMulticasting

Internet Protocol:Provides connectionless, best-effort delivery routing of datagrams, is not concerned with the content of the datagrams; looks for a way to move the datagrams to their destination

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20.1 ARP20.1 ARP

Mapping

Packet Format

Encapsulation

Operation

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Figure 20.2 ARP operation

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Figure 20.3 ARP packet

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Figure 20.4 Encapsulation of ARP packet

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Figure 20.5 Four cases using ARP

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An ARP request is broadcast; an ARP reply is unicast.

NoteNote::

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Example 1Example 1

A host with IP address 130.23.3.20 and physical address B23455102210 has a packet to send to another host with IP address 130.23.43.25 and physical address A46EF45983AB. The two hosts are on the same Ethernet network. Show the ARP request and reply packets encapsulated in Ethernet frames.

SolutionSolution

Figure 20.6 shows the ARP request and reply packets. Note that the ARP data field in this case is 28 bytes, and that the individual addresses do not fit in the 4-byte boundary. That is why we do not show the regular 4-byte boundaries for these addresses. Note that we use hexadecimal for every field except the IP addresses.

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Figure 20.6 Example 1

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20.2 IP20.2 IP

Datagram

Fragmentation

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Figure 20.7 IP datagram

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IP Datagram Fields

VERS - Version number HLEN - - Header length, in 32 bit words Type of Service - HHH HHH HHHHHHHH HHHHHH HH HHHHHHH Total Length - HHHHHH H HHHH ,+ Identification, Flags, Frag . Offset - HHHHHHHH HHHHHHHHH

tion of datagrams to allow differing MTU's in the Internetwor k

TTL - - - Time To Live Protocol - - The upper layer (Layer 4) protocol sending and re

ceiving the datagram Header Checksum - HH HHHHHHHHH HHHHH HH HHH HHHHHH Source IP Address and Destination IP Address - - 32 bit

IP addresses IP Options - HHHHHHHHH HHH HHHH, , ,

r options Data - HHHH

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Figure 20.8 Multiplexing

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Figure 20.9 Example of checksum calculation

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Figure 20.11 Fragmentation example

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Figure 20.10 MTU

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20.3 ICMP20.3 ICMP

Types of ICMP Messages

IP gives unreliable and connectionless datagram delivery.So it gives best-effort delivery service.

Efficient use of network resources.

No error control/reporting.No messaging capability.

ICMP = Internet Control Message Protocol

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Figure 20.12 ICMP encapsulation

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ICMP always reports error messages to the original source.

NoteNote::

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Figure 20.13 Error-reporting messages

Packet discarded,router/host cannotdeliver datagram.

Packet discarded,router/host iscongested. AddedFlow control to IP.

Packet discardedrouter/host getsDatagram with 0 TTL, or fragments arrive late.

Packet discarded,router/host getsambiguous datagram.

Packet sent to wrong router.

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There is no flow control or congestion control mechanism in IP.

NoteNote::

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Figure 20.14 Query messages

Identify networkcommunication problems betweensystems (host or routers)

Get round-trip time,Synchronize clocks.

Get mask to identifynetwork or subnetworkpart of IP address.

Get information of alive and functioningrouters.

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20.4 IPv620.4 IPv6

IPv6 Addresses

Categories of Addresses

IPv6 Packet Format

Fragmentation

ICMPv6

Transition

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WORLD INTERNET USAGE AND POPULATION STATISTICS

World RegionsPopulation ( 2008 Est.)

Internet Users

Dec/31, 2000

Internet Usage,

Latest Data

%Population(Penetratio

n)

Usage % of

World

Usage Growth2000-2008

Africa 955,206,348 4,514,400 51,065,630 5.3 % 3.5 % 1,031.2 %

Asia 3,776,181,949

114,304,000578,538,25

715.3 % 39.5 % 406.1 %

Europe 800,401,065 105,096,093384,633,76

548.1 % 26.3 % 266.0 %

Middle East 197,090,443 3,284,800 41,939,200 21.3 % 2.9 % 1,176.8 %

North America 337,167,248 108,096,800248,241,96

973.6 % 17.0 % 129.6 %

Latin America/

Caribbean576,091,673 18,068,919

139,009,209

24.1 % 9.5 % 669.3 %

Oceania / Australia 33,981,562 7,620,480 20,204,331 59.5 % 1.4 % 165.1 %

WORLD TOTAL 6,676,120,288

360,985,492 1,463,632,361

21.9 % 100.0 %

305.5 %NOTES: (1) Internet Usage and World Population Statistics are for June 30, 2008. (2) Population numbers are based on data from the US Census Bureau . (3) Internet usage information comes from data published by Nielsen//NetRatings, by the International Telecommunications Union, by local NIC, and other reliable sources.

Source: www.internetworldstats.com.

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IPv6

การปร�บปรงที่� ชั�ดเจนของ IPv6 คื�อคืวามยาวของ IP address เปลี่� ยนจาก 32 bits เป�น 128 bits การขยายด�งกลี่�าวเพื่� อรองร�บการขยายของ

อ�นเตอร เน!ต แลี่ะเพื่� อหลี่�กเลี่� ยงการขาดแคืลี่นของต%าแหน�งเคืร�อข�าย

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Address space

ส่�วนแตกต�างที่� เด�นที่� ส่ดของ IPv6 ซึ่( งพื่�ฒนามา จาก IPv4 คื�อ

• IPv4 ใชั+ address ยาว 32-bit ( กว�า 4 พื่�นลี่+าน addresses)

• IPv6 ใชั+ address ยาว 128-bit addresses (กว�า 3.4×1038 addresses)

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Figure 20.15 IPv6 address

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Figure 20.16 Abbreviated address

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Figure 20.17 Abbreviated address with consecutive zeros

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Figure 20.18 CIDR address

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Figure 20.19 Format of an IPv6 datagram

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Figure 2 Format of an IPv6 datagram

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Table 4 Comparison between IPv4 and IPv6 packet headers

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Figure 20.20 Comparison of network layers in version 4 and version 6

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Technology Technology converging toconverging to 4G4G คาดการณ์ก�นว่�าทุ�กเทุคโนโลยี�จะต้�องใช้� IP เป็�นโป็รโต้คอลพื้!"นฐาน

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Why so slow?

2005As of December 6, IPv accounts for a tiny percentage of the live a

ii iii iiiiiiii-iiiiiiiiii iiiiiiiii iiiii ii ,iiiii domi nated 4by IPv .

Slow because of classless addressing network address translation (NAT),

When will we runout of IPv4 addresses? APNIC (2003): the available space would last u

ntil2023 , Cisco Systems (2005): available addresses

would be exhausted in 4–5 years.

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When is the change?

6Although adoption of IPv has been slow,ii ii 2008 iii , United States government 6systems must support IPv .

Meanwhile iiiii is planning to get a head start implementing IPv6 with their 5 year plan for the China Next Gen iiiiiiiii .

The country of iiiii changed to IPv6.

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TRANSITION FROM IPv4 TO IPv6TRANSITION FROM IPv4 TO IPv6

Because of the huge number of systems on the Because of the huge number of systems on the Internet, the transition from IPv4 to IPv6 Internet, the transition from IPv4 to IPv6 cannot cannot happen suddenlyhappen suddenly. It takes a considerable amount . It takes a considerable amount of time before every system in the Internet can of time before every system in the Internet can move from IPv4 to IPv6. The transition must be move from IPv4 to IPv6. The transition must be smooth to prevent any problems between IPv4 and smooth to prevent any problems between IPv4 and IPv6 systems. IPv6 systems.

Dual StackTunneling

Topics discussed in this section:Topics discussed in this section:

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Figure 20.21 Three transition strategies

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Figure 20.22 Three transition strategies

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Figure 20.23 Tunneling

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Figure 20.24 Header translation

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ในส่�วนของประเที่ศไที่ย

ในป/จจบ�นได+ม�การก�อต�0งคืณะที่%างานระด�บ ประเที่ศข(0นภายใต+ชั� อ Thailand IPv6

Forum ก�จกรรมในป/จจบ�นของ Thailand IPv6

Forum ได+แก� การเข+าร�วมเป�นส่มาชั�กของAsia-Pacific IPv6 Task Force แลี่ะ

การเชั� อมต�อแบบ Native IPv6

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Summary

Internet Protocol Provides connectionless, best-effort

delivery routing of datagrams, is not concerned with the content of the datagrams;

looks for a way to move the datagrams to their destination

ARP Find MAC address of next-hop host

RARP (obsolete) ICMP

Provi des error control and messaging iiiiiiiiiiii in unicasting