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

2. Class Agenda 4/8/16 Learning Objectives
Lesson Presentation and Discussions.
Discussion on Assignments.
Discussion on Lab Activities.
Break Times as per School Regulations.
Quiz 2-Open book- Chapter 3, 4 and 5

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

4. 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

5. EXPLORE: CONCEPTS

6. IPv4: Address Structure
9/16/2018
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:
IPv4 networks can be classful or classless
RFC 791 Internet Protocol (
RFC 1166 Internet Numbers (
(c) ITT Educational Services, Inc.

7. IPv4: Classful Network Architecture
9/16/2018
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)
Class D and E are not used for hosts, as is illustrated by the next slide
(c) ITT Educational Services, Inc.

8. IPv4: Classful Network Breakdown
9/16/2018
IPv4: Classful Network Breakdown
Class
# of
Networks
# of Nodes
Address Range
A (large)
128
16,777,216 to
B (medium)
16,384
65,536 to
C (small)
2,097,152
256 to
D (multicast)
N/A to
E (future use) to
This method of addressing was not very flexible and IP address shortage was inevitable
Because D and E were reserved for other purposes, there are a maximum of 16,843,011 available IP addresses.
This does not count reserved addresses within each class.
(c) ITT Educational Services, Inc.

9. IPv4: Networks versus Nodes
9/16/2018
IPv4: Networks versus Nodes
Tradeoff between number of networks and number of nodes
Class A = 1 octet to identify network, 3 to identify nodes
Class B = 2 octets to identify network, 2 to identify nodes
Class C = 3 octets to identify network, 1 to identify nodes
(c) ITT Educational Services, Inc.

10. IPv4: CIDR Replacement for classful network architecture (1993)
9/16/2018
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
Flexible network allocation
Minimal IP address waste
RFC 4632 Classless Inter-Domain Routing (CIDR) (
(c) ITT Educational Services, Inc.

11. IPv4: Dot Notation to Binary
9/16/2018
IPv4: Dot Notation to Binary
The instructor should discuss the difference between decimal (base 10) and binary (base 2) by noting the different manner in which the common decimal values are represented in binary format. It may be helpful in a classroom environment to write on a white board the binary place values (2^0, 2^1, 2^2, etc.) to provide students with a framework. Using this slide, the Instructor should draw attention to the first decimal value, and then show the addition of the binary place values for all “1”s.
Example: For decimal 168, the Instructor should identify the highest value (by position) of 128, then locate the next “1” at 32 and add that value to the previous total of 128 to obtain =160, then locate the final “1” at 8 and add that value to the previous total of 160 to obtain 168+8=168 and draw the students’ attention back to the original matching decimal value.
Decomposition of an arbitrary decimal value provided by a student (255 and below) can be performed using a white board by first laying out eight spaces and identifying the 2’s value for each, then writing down the decimal value for reference. Decomposition begins by finding the highest 2’s position with a decimal equivalent value under or exactly equal to the arbitrary decimal value and putting a “1” above that position and subtracting the equivalent value from the original, performing the same process on the remainder until the remainder is zero. Then “0” can be placed in all of the empty spaces to fill out the full byte.
Example: For the arbitrary value of 17, the highest 2’s value below or equal is the 5th position from the right (2^4=16), leaving a remainder of 1 which matches the 1st position from the right (2^0=1). Thus, the result will appear as: ___ ___ ___ _1_ ___ ___ ___ _1_, with zeros as:
(c) ITT Educational Services, Inc.

12. IPv4: Private Addresses
9/16/2018
IPv4: Private Addresses
Not routable through public routers
Network Address Translation (NAT) maps internal addresses to public routable addresses
Private Address Ranges to to to
RFC 1918 Address Allocation for Private Internets (
As discussed earlier, there are a limited number of IP addresses
Organizations may find it difficult to acquire enough public addresses
The instructor should stress that organizations should never use unauthorized public addresses, even if not connected to the Internet.
(c) ITT Educational Services, Inc.

13. IPv6: Address Structure
9/16/2018
IPv6: Address Structure
128 bit addresses
First 64 bits identify network
Last 64 bits identify host (based on MAC address)
Maximum number of 2128 addresses (> 340 undecillion)
1 undecillion = 1,000,000,000,000,000,000,000,000,000,000,000,000
RFC 4291 IP Version 6 Addressing Architecture (
While the number of addresses is not infinite, the world is unlikely to run out of addresses in the foreseeable future.
(c) ITT Educational Services, Inc.

14. IPv6: Address Notation 8 groups of 4 hexadecimal numbers 9/16/2018
(c) ITT Educational Services, Inc.

15. IPv6: Address Compression
9/16/2018
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:db8::53:0:4
Only one set of :: can exist in an address
It is important to stress that only one set of double colons can exist in an address in order to keep track of the missing groups of zeros.
Because we know there must be 8 sets of numbers, we know that in the above example 3 groups of 0s have been compressed.
(c) ITT Educational Services, Inc.

16. One-to-First-of-Many
9/16/2018
IPv6: Address Types
Unicast
One-to-One
Packets are delivered to a single node
Anycast
One-to-First-of-Many
Packets are delivered to one of a group of nodes
Multicast
One-to-Many
Packets are delivered to many nodes
The Instructor should call attention to the lack of a Broadcast (one-to-all in a subnet) addressing system. In order to provide greater extensibility in the much larger address space of Ipv6, Multicasting to a group of nodes subscribing to a single multicast address provides the same functionality as broadcast did in IPv4.
Anycast functions similarly, but by sending packets only to the nearest host (AAAA) address, which then forwards packets to the remaining subscribing group members. This allows for a change in packet routing during an extended transfer in case of network saturation or failure along a particular route.
(c) ITT Educational Services, Inc.

17. IPv6: Global versus Local Unicast
9/16/2018
IPv6: Global versus Local Unicast
Interfaces in IPv6 have at least two addresses:
Link-local
Non-routable
Inter-node identification between neighbors within the same LAN segment
May be automatically or manually assigned
Equivalent to private IPv4 address
Unicast
Globally unique
Routed communications between non-neighbor nodes
Computed using the interface MAC address
Equivalent to public IPv4 address
(c) ITT Educational Services, Inc.

18. EXPLORE: PROCESSES

19. Elements of an IPv4 Address Schema
9/16/2018
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
This is the traditional method of subnetting.
(c) ITT Educational Services, Inc.

20. IPv4 Schema: Determine Network
9/16/2018
IPv4 Schema: Determine Network
How many hosts (nodes)?
Workstations
Servers
Other
Number of nodes determines network class
Class
Networks
Nodes
Address Range
A (large)
128
16,777,216 to
B (medium)
16,384
65,536 to
C (small)
2,097,152
256 to
(c) ITT Educational Services, Inc.

21. IPv4 Schema: Subnets How many subnets are needed?
9/16/2018
IPv4 Schema: Subnets
How many subnets are needed?
Security
Services
Organizational structure
How many hosts for each subnet?
# of hosts per subnet determines subnet mask
Net Bits
Subnet Mask
Addresses
/20
4096
/21
2048
/22
1024
/23
512
/24
256
/25
128
/26 64
/27 32
/28 16
/29 8
/30 4
RFC 950 Internet Standard Subnetting Procedures (
(c) ITT Educational Services, Inc.

22. IPv4 Example Network ID 10.0.0.0 (Class A) Subnet Mask 255.255.255.0
9/16/2018
IPv4 Example
Network ID
(Class A)
Subnet Mask
Mask Bits 24
Subnet Bits 16
Total Addresses
255
IP Address (gateway)
Broadcast Address
Total Host (assignable addresses)
254
CIDR Notation
/24
(c) ITT Educational Services, Inc.

23. Elements of an IPv6 Addressing Schema
9/16/2018
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
(c) ITT Educational Services, Inc.

24. IPv6 Schema: Subnets Support Business Needs
9/16/2018
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
RFC 5942 IPv6 Subnet Model (
Because the IPv6 address space is so vast, subnetting IPv6 address space follows business rules and matters of convenience rather than address control concepts as with the IPv4 address space, where governments compete for Class A assignments, and even a portion of a Class C address space is a valuable commodity.
The Instructor should address the global suitability of IPv6 compared to the earlier IPv4 addressing scheme, where an early-adopter such as a single USA university may own a larger address space than many countries elsewhere in the world.
(c) ITT Educational Services, Inc.

25. IPv6 Schema: Subnetting
9/16/2018
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)
The instructor should draw attention to the sheer size of the maximum possible address space for the IPv6 system, noting that while the default 64-bit network address for IPv6 leaves 2^64 possible node addresses, the entire IPv4 Internet only allows just 2^32 total possible addresses all together.
The classless nature of IPv6 should be noted, along with brief discussion of the reason subnet broadcasts would not work if every ISP was given its own /32 IPv6 subnet (with 2^96 possible node addresses). This would amount to broadcasting packets to 2^64 copies of the entire Internet at once.
(c) ITT Educational Services, Inc.

26. IPv6: Subnet Segmentation
9/16/2018
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
The instructor should drawn attention to the significant capacity for subnets at the /32 and /48 level, plus the sheer size of nodes possible at the LAB segment level.
Learner engagement should be enhanced through discussion of the proliferation of personal devices, environmental sensors, and other similar emerging technologies expected to require millions of individual addresses. Discussion should include asking students to consider the number of devices needed to monitor the power consumption of all buildings in a “smart city.”
(c) ITT Educational Services, Inc.

27. EXPLORE: ROLES

28. Role of IP Addressing in Network Routing
9/16/2018
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
(c) ITT Educational Services, Inc.

29. EXPLORE: CONTEXTS

30. IPv4 and IPv6 in Context Most devices still using IPv4
9/16/2018
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
As of October 2010:
243 (83%) of the 294 top-level domains (TLDs) in the Internet supported IPv6 to access their domain name servers
About 1.4 million domains (1%) had IPv6 address records in their zones
Mobile telephone service transitioning from 3G systems to 4G
Voice is provisioned as Voice over Internet Protocol (VoIP); requires use of IPv6
All major PC and server operating systems support IPv6
(c) ITT Educational Services, Inc.

31. EXPLORE: RATIONALE

32. 9/16/2018
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.
(c) ITT Educational Services, Inc.

33. 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

34. Lab 4.2 Designing IP Addressing Schema for Networking Infrastructure
Assignments
Quiz 4.1 Quiz 2
Lab 4.2 Designing IP Addressing Schema for Networking Infrastructure
Assignment 4.3 IP Address Schema Design for a Medium- Sized Business