Network Layer Protocols ARP IPv 4 ICMP IPv

Network Layer Protocols: ARP, IPv 4, ICMP, IPv 6 and ICMPv 6 20. 1 ARP 20. 2 IP 20. 3 ICMP 20. 4 IPv 6 Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 1 Protocols at network layer Internet Group Management Protocol Multicasting Reversed ARP Obsolete Internet Control Message Protocol Provides error control and messaging capabilities in unicasting Address Resolution Protocol Find MAC address of next-hop host 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©The destination Mc. Graw-Hill Companies, Inc. , 2004

20. 1 ARP Mapping Packet Format Encapsulation Operation Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 2 Mc. Graw-Hill ARP operation ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 3 Mc. Graw-Hill ARP packet ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 4 Mc. Graw-Hill Encapsulation of ARP packet ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 5 Mc. Graw-Hill Four cases using ARP ©The Mc. Graw-Hill Companies, Inc. , 2004

Note: An ARP request is broadcast; an ARP reply is unicast. Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Example 1 A host with IP address 130. 23. 3. 20 and physical address B 23455102210 has a packet to send to another host with IP address 130. 23. 43. 25 and physical address A 46 EF 45983 AB. The two hosts are on the same Ethernet network. Show the ARP request and reply packets encapsulated in Ethernet frames. Solution 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. Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 6 Mc. Graw-Hill Example 1 ©The Mc. Graw-Hill Companies, Inc. , 2004

20. 2 IP Datagram Fragmentation Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 7 Mc. Graw-Hill IP datagram ©The Mc. Graw-Hill Companies, Inc. , 2004

IP Datagram Fields n n n VERS -Version number HLEN -Header length, in 32 -bit words Type of Service -How the datagram should be handled Total Length -Total length, header + data Identification, Flags, Frag. Offset -Provides fragmentation of datagrams to allow differing MTU's in the Internetwork TTL -Time-To-Live Protocol -The upper-layer (Layer 4) protocol sending and receiving the datagram Header Checksum -An integrity check on the header Source IP Address and Destination IP Address 32 - -bit IP addresses IP Options -Network testing, debugging, security, and other options Data -Data Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 8 Mc. Graw-Hill Multiplexing ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 9 Mc. Graw-Hill Example of checksum calculation ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 11 Mc. Graw-Hill Fragmentation example ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 10 Mc. Graw-Hill MTU ©The Mc. Graw-Hill Companies, Inc. , 2004

20. 3 ICMP 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 Types of ICMP Messages Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 12 Mc. Graw-Hill ICMP encapsulation ©The Mc. Graw-Hill Companies, Inc. , 2004

Note: ICMP always reports error messages to the original source. Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 13 Packet discarded, router/host cannot deliver datagram. Error-reporting messages Packet discarded router/host gets Datagram with 0 TTL, or fragments arrive late. Packet discarded, router/host is congested. Added Flow control to IP. Mc. Graw-Hill Packet sent to wrong router. Packet discarded, router/host gets ambiguous datagram. ©The Mc. Graw-Hill Companies, Inc. , 2004

Note: There is no flow control or congestion control mechanism in IP. Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 14 Identify network communication problems between systems (host or routers) Mc. Graw-Hill Query messages Get mask to identify network or subnetwork part of IP address. Get round-trip time, Synchronize clocks. Get information of alive and functioning routers. ©The Mc. Graw-Hill Companies, Inc. , 2004

20. 4 IPv 6 Addresses Categories of Addresses IPv 6 Packet Format Fragmentation ICMPv 6 Transition Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

WORLD INTERNET USAGE AND POPULATION STATISTICS World Regions Africa Population 2008 )Est(. Internet Users Dec , 31/ 2000 Internet Usage, Latest Data % Population (Penetration ( Usage %of World Usage Growth 20002008 955, 206, 348 4, 514, 400 51, 065, 630 5. 3% 3. 5% 1, 031. 2% 3, 776, 181, 949 114, 304, 000 578, 538, 257 15. 3% 39. 5% 406. 1% Europe 800, 401, 065 105, 096, 093 384, 633, 765 48. 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, 800 248, 241, 969 73. 6% 17. 0% 129. 6% Latin America/Caribbea n 576, 091, 673 18, 068, 919 139, 009, 209 24. 1% 9. 5% 669. 3% 33, 981, 562 7, 620, 480 20, 204, 331 59. 5% 1. 4% 165. 1% Asia Oceania / Australia NOTES (1) : Internet Usage and World Population Statistics are for June 30, 2008. 100. 0 1, 463, 632, 36 6, 676, 120, 288 360, 985, 492 21. 9% 305. 5% (2)Population are based on data from the US Census Bureau. WORLD TOTALnumbers 1 % (3)Internet usage information comes from data published by Nielsen//Net. Ratings , by the International Telecommunications Union, by local NIC, and other reliable sources. Mc. Graw-Hill Source: www. internetworldstats. com. ©The Mc. Graw-Hill Companies, Inc. , 2004

Address space ����������� IPv 6 ������� IPv 4 ��� • IPv 4 ��� address ��� 32 -bit ) ���� 4 ������� addresses ( • IPv 6 ��� address ��� 128 -bit addresses ) ���� 3. 4× 1038 addresses( Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 15 Mc. Graw-Hill IPv 6 address ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 16 Mc. Graw-Hill Abbreviated address ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 17 Mc. Graw-Hill Abbreviated address with consecutive zeros ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 18 Mc. Graw-Hill CIDR address ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 19 Mc. Graw-Hill Format of an IPv 6 datagram ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 2 Format of an IPv 6 datagram Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Table 4 Comparison between IPv 4 and IPv 6 packet headers Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 20 Mc. Graw-Hill Comparison of network layers in version 4 and version 6 ©The Mc. Graw-Hill Companies, Inc. , 2004

Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Why so slow? n n As of December 2005 , IPv 6 accounts for a tiny percentage of the live addresses in the publiclyaccessible Internet, which is still dominated by IPv 4. Slow because of n n n classless addressing network address translation) NAT), When will we runout of IPv 4 addresses? n n Mc. Graw-Hill APNIC : (2003) the available space would last until 2023 , Cisco Systems (2005): available addresses would be exhausted in 4– 5 years. ©The Mc. Graw-Hill Companies, Inc. , 2004

When is the change? n n n Although adoption of IPv 6 has been slow, as of 2008, all United States government systems must support IPv 6. Meanwhile China is planning to get a head start implementing IPv 6 with their 5 year plan for the China Next Generation Internet. The country of Japan changed to IPv 6. Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

TRANSITION FROM IPv 4 TO IPv 6 Because of the huge number of systems on the Internet, the transition from IPv 4 to IPv 6 cannot happen suddenly. It takes a considerable amount of time before every system in the Internet can move from IPv 4 to IPv 6. The transition must be smooth to prevent any problems between IPv 4 and IPv 6 systems. Topics discussed in this section: Dual Stack Tunneling Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 21 Mc. Graw-Hill Three transition strategies ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 22 Mc. Graw-Hill Three transition strategies ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 23 Mc. Graw-Hill Tunneling ©The Mc. Graw-Hill Companies, Inc. , 2004

Figure 20. 24 Mc. Graw-Hill Header translation ©The Mc. Graw-Hill Companies, Inc. , 2004

�������� n n ��������������������� Thailand IPv 6 Forum �������������� Asia-Pacific IPv 6 Task Force ������ Native IPv 6 Mc. Graw-Hill ©The Mc. Graw-Hill Companies, Inc. , 2004

Summary n Internet Protocol n n n ARP n n n 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 Find MAC address of next-hop host RARP) obsolete( ICMP n Mc. Graw-Hill Provides error control and messaging capabilities in unicasting ©The Mc. Graw-Hill Companies, Inc. , 2004