1. Oct 2000C. Watters1 NAMES and ADDRESSES What’s in a name, anyway? 1011010011001110000111001100110

2. Oct 2000C. Watters2 Internet Node Addresses Each node has unique network name  hierarchical composition based on name granting authority  www.cs.dal.ca unique network address  hierarchical composition based on topographical  129.173.66.61

3. Oct 2000C. Watters3 How do we get the network address from network name? Domain name servers translate name to network address

4. Oct 2000C. Watters4 Domain Hierarchy DNS hierarchy can be viewed as a tree Node in the tree corresponding to a domain. Leaves in the tree corresponding to the host being named. DNS names are processed from right to left and use period as separator.

5. Oct 2000C. Watters5 Domain Hierarchy educomgovmilorgnetukca arizona….mitacmieee csecephysics bascheopt

6. Oct 2000C. Watters6 Name Server Domain name hierarchy is partitioned into subtrees called zones Zone: an administrative authority responsible for that part of hierarchy Each Zone implements part of name server (translates to network address). DNS is an hierarchy of name servers.

7. Oct 2000C. Watters7 Name Server Root name server Dalhousie name server Gov. Canada name server …... Cs name server IS2 name server

8. Oct 2000C. Watters8 Name Server Role of name servers each name server contains a record for each lower level server. translates this name part into IP address.

9. Oct 2000C. Watters9 Name Server Record Example 1st level : Second level: Third level

10. Oct 2000C. Watters10 Name Resolution Client Local name server Root name server Arizona name server CS name server cheltenham.cs.arizona.edu 1 2 Arizona.edu, 128.196.128.233 cheltenham.cs.arizona.edu Cs.arizona.edu, 192.12.69.5 cheltenham.cs.arizona.edu cheltenham.cs.arizona.edu, 192.12.69.60 3 4 5 6 7 8

11. Oct 2000C. Watters11 Where is the work done? “lookup” directories are distributed!! Grouped into domains based on names each domain has a local name server process

12. Oct 2000C. Watters12 What is the network IP (IPv4) address? 32 bits (4 bytes) per node schemes class-based addresses subnet addresses classless addresses

13. Oct 2000C. Watters13 Class-based Addressing IPv4 General form network.host eg. UC Berkeley is 128.32.0.0 eg. Borg 129.173.66.61 large networks have few network bytes (more room for hosts on them) small networks have longer network address (fewer hosts expected)

14. Oct 2000C. Watters14 Classes Class A - large networks (net 1 byte/host 3) Class B - medium networks ( net 2 bytes/host 2) Class C - small networks (3 bytes/host 1) 0 1 0 1 1 0 host Network

15. Oct 2000C. Watters15 Example 140.179.220.200 140 179 220 200 10001100 10110011 11011100 11001000

16. Oct 2000C. Watters16 Look again at binary addresses???? 1 byte network number starting with 0 0111 1111 is the biggest number so 126 is the biggest A network address (126/2M hosts) written as 126.hostbyte1.hostbyte2.hostbyte3 2 byte network number starting with 10 1000 0000 0000 0000 so starts 128 1011 1111 1111 1111 up to 191 written as 129.173.hostbyte1.hostbyte2 (64k/64k hosts) 3 byte network number starting with 11 1100 000 000 0000 0000 0000 starts 192 up to 223 written as 198.174.66.hostbyte (2mill.values/256 hosts )

17. Oct 2000C. Watters17 So what’s the big problem?

18. Oct 2000C. Watters18 IPv6 Features 128 bits address space Advanced Routing Capability Better Options Support Better Quality of service Support Authentication and Security

19. Oct 2000C. Watters19 IPv6 address architecture 128 bits of address space representation of address (hexadecimal) 56DF:C4CC:A44B:5528:8E52:4224:ACBB:01EE special syntax CDFA:0000:0000:0000:0000:0000:11E7:D45A =CDFA::11E7:D45A totally 3.4 x 10 38 addresses

20. Oct 2000C. Watters20 Header of IPv6 is simpler: Header of IPv6 Header of IPv4 IPv6 increases the length of the IP header from 20 bytes to 40 bytes, but IPv6 header contains fewer fields, thus, it speed up routing.

21. Oct 2000C. Watters21 Summary IPv6 simplifies packet header formats. IPv6 provides a much larger address space of 128 bits. This overhead in the header has been reduced by simplifying the header formats. IPv6 supports authentication and encryption of packet contents at the network layer.

22. Oct 2000C. Watters22 IPv4 address transits to IPv6 IPv4-compatible IPv6 address 80 bits 16 bits 32 bits 0000…000 0000 IPv4 address

23. Oct 2000C. Watters23 Transition Planning Maintain complete IPv4 routing system until run-out Upgrade IPv4 router to IPv4/6 dual router Building up IPv6 only (6 bone) Shutdown IPv4 in areas where there is no need for IPv4

24. Oct 2000C. Watters24 Future Successful transition to IPv6 is depended on the standards(protocols), products and management infrastructure. There are other schemes in the works!!!