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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