IS3120 Network Communications Infrastructure Unit 4

1. IS3120 Network Communications Infrastructure Unit 4 IP Addressing Schema Designs for a Layer 2/Layer 3 IP Network Infrastructure

2. Learning Objective • Translate IPv4 and IPv6 IP addressing schemas and perform logical IP addressing schema designs.

3. Key Concepts • IPv4 addressing structure • IPv6 addressing structure • Alignment of subnet mask addressing to appropriate number of IP subnetworks • IP addressing schema design using IPv4 for Layer 2 and Layer 3 networking • IP addressing schema design using IPv6 for Layer 2 and Layer 3 networking

4. EXPLORE: CONCEPTS

5. IPv4: Address Structure • 32-bit addresses (4 bytes) • Usually displayed in dot notation • 4 separate 8-bit numbers (octets) • Octets separated by periods • Octet value is between 0 and 255 • Example: 192.168.0.1 • IPv4 networks can be classful or classless

6. IPv4: Classful Network Architecture • IP addresses originally organized into five classes: A, B, C, D, and E • A, B, and C used for networks • Each class restricted to a particular IP address range • Range based on number of nodes needed • Maximum number of 4,294,967,296 addresses (232)

7. IPv4: Classful Network Breakdown

8. IPv4: Networks versus Nodes

9. IPv4: CIDR • Replacement for classful network architecture (1993) • Temporary solution for IP address shortage • Networks are split into groups of IP addresses called CIDR blocks

10. IPv4: Dot Notation to Binary

11. IPv4: Private Addresses • Not routable through public routers • Network Address Translation (NAT) maps internal addresses to public routable addresses

12. IPv6: Address Structure • 128 bit addresses • First 64 bits identify network • Last 64 bits identify host (based on MAC address) • Maximum number of 2128addresses (> 340 undecillion) 1 undecillion = 1,000,000,000,000,000,000,000,000,000,000,000,000

13. IPv6: Address Notation • 8 groups of 4 hexadecimal numbers

14. IPv6: Address Compression • Drop leading 0s in each group 2001:0db8:0000:0000:0000:0053:0000:0004 becomes 2001:db8:0:0:0:53:0:4 • Replace the first group of 0s with :: 2001:0db8:0000:0000:0000:0053:0000:0004 becomes 2001:db8::53:0:4 • Only one set of :: can exist in an address

15. IPv6: Network Prefix • Address block 2001:db8::/32 • Range: 2001:db8:: to 2001:0db8:ffff:ffff:ffff:ffff:ffff:ffff • Any IP address sharing the same initial 32 bits is in the same Internet network, leaving 32 bits for further sub-netting.

16. IPv6: Address Types

17. IPv6: Unicast Addressing • Single device • Similar to IPv4 CIDR • Global or local (public or private) • Can contain embedded IPv4 addresses • Network prefix set to 0 • ::FFFF:192.168.0.4

18. IPv6: Global versus Local Unicast • Interfaces in IPv6 have at least two addresses:

19. IPv6: Unicast Host Identifier • Calculated from interface’s 48-bit MAC address • MAC is assigned by manufacturer: 1c:6f:65:35:85:6d 00011100 01101111 01100101 00110101 10000101 01101101 • EUI-64 inserts ff:fe as the middle 16 bits: 1c:6f:65:ff:fe:35:85:6d 00011100 01101111 01100101 1111111111111110 00110101 10000101 01101101 • If the host address is globally unique the 7th bit is inverted: 1e:6f:65:ff:fe:35:85:6d 00011110 01101111 01100101 11111111 11111110 00110101 10000101 01101101 • Any IP address sharing the same initial 32 bits is in the same Internet network, leaving 32 bits for sub-netting.

20. IPv6: Multicast Addressing

21. IPv6: Multicast Assignment • Interfaces in IPv6 have at least two multicast assignments: • Solicited-node • Used to validate host identifier uniqueness • Announces interface to neighbors • All-hosts • Communicate with all nodes within a LAN segment

22. IPv6: Multicast Addressing Example: • Solicited-node addresses • Translated from a node’s unicast address

23. IPv6: Reserved Multicast Addresses • ff02::1 is all nodes • ff02::2 is all routers • ff02::101 is all Network Time Protocol (NTP) servers • ff02::fb is all multicast DNS servers

24. IPv6: Anycast Addressing • New to IPv6, no IPv4 equivalent • Can be translated from unicast address • Change node identifier bits to all 0s or all 1s except the last 7 bits • Associated with a unique identifier • Each LAN segment can have 126 unique anycast IDs

25. IPv6: Anycast Addressing • Node address of all 0s • Subnet-router communications • Takes the place of a default gateway in IPv4 • Node address of 1s except the last 7 bits • 0x00 (0000000) through 0x7d (0111101) may be designated Anycast identifiers • 0x7e (0111110) and 0x7f (0111111) are reserved

26. EXPLORE: PROCESSES

27. Elements of an IPv4 Address Schema • Network ID (aka network address) • First address of the block • Subnet mask • Broadcast address • Last address of the block • If multiple subnets • Each subnet has its own network ID and broadcast address

28. IPv4Schema: Determine Network • How many hosts (nodes)? • Workstations • Servers • Other • Number of nodes determines network class

29. IPv4Schema: Subnets • How many subnets are needed? • Security • Services • Organizational structure • How many hosts for eachsubnet? • # of hosts per subnetdetermines subnet mask

30. IPv4 Example

31. Elements of an IPv6 Addressing Schema • Internetworking is generally automatic • Assignment of unicast host identifiers • Network and gateway mapping through Neighbor Discovery • Link-local addressing is manual or automatic • Configurable scopes • Admin Level • Site Level (deprecated) • Organization Level

32. Types of IPv6 Addresses • Enclose IPv6 addresses in brackets [] to specify a particular port • Example:telnet [201:0db8::53:0:4]:23 for port 23

33. IPv6 Schema: Subnets Support Business Needs • Segmentation across routers to limit network congestion on critical subnets • Regulatory mandates requiring transport isolation of certain data categories • Logical segmentation of neighbor nodes based on disparate facility locations • Isolation for each client or function

34. IPv6 Schema: Subnetting • Classless • Notation is similar to IPv4 CIDR addressing notation. • Example: 2001:0db8:0:0:0:53:0:4/16 • Defines 2001 (the first 16 bits) as the network address • Subnets of 2112 node addresses each • Further subnetting is possible (hierarchical)

35. IPv6: Subnet Segmentation • Each Provider assigned a /32 network (65536 /48 Subscriber subnets) • A Subscriber assigned a /48 subnet (65536 /64 LAN segments) • A single /64 LAN segment is 264 nodes • Further segmentation administratively assigned through Admin-, Site-, and Organizational-scope specification

36. EXPLORE: ROLES

37. Role of IP Addressing in Network Routing • IP addressing is based on hosts and networks • End hosts are assigned IP addresses • Subnets of IP host addresses are divided and grouped together • IP address are used to route packets and are essential to getting information to the proper destination

38. EXPLORE: CONTEXTS

39. IPv4 and IPv6 in Context • Most devices still using IPv4 • Compatibility with IPv6 networking is mainly a software or firmware issue • American Registry for Internet Numbers (ARIN) suggests that all Internet servers be prepared to serve IPv6-only clients by January 2012

40. EXPLORE: RATIONALE

41. Rationale • The number of network-enabled devices has grown beyond IPv4’s address capacity. • IPv6 provides a more globally equitable distribution of network addresses than the legacy IPv4 system which provides more addresses to early-adopters (US universities) than to many governments elsewhere in the world.

42. Summary • In this presentation, the following were covered: • IPv4 addressing • Classful and classless networking (IPv4) • IPv6 addressing • IPv4 address schema design • IPv6 address schema design