1. NT1210 Introduction to Networking
Unit 8:
Chapter 8, The Internet Protocol (IP) 1

2. Class Agenda 2/9/16 Learning Objectives Quiz 2 in the next class.
Lesson Presentation and Discussions
Lab Activities will be performed in class.
Assignments will be given in class.
Break Times. 10 Minutes break in every 1 Hour.
Note: Submit all Assignment and labs due today.

3. Objectives Explain the functionality of typical network protocols.
Plan and design an IP network by applying subnetting skills.
Categorize TCP/IP protocols according to network model layers.
Describe how TCP/IP addressing moves data packets through networks. 3

4. Introducing the Internet Protocol (IP)
TCP/IP Model review: Layers 1 and 2 Protocols
Example LAN/WAN Standards and Types in the TCP/IP Model 4
Figure 8-1

5. Introducing the Internet Protocol (IP)
TCP/IP Model review: Upper layers define non-physical (logical) networking functions
Various Perspectives on the TCP/IP Model and Roles 5
Figure 8-2

6. Introducing the Internet Protocol (IP)
Network Layer protocols
IP: Most important protocol defined by Network layer
Almost every computing device on planet communicates, and most use IP to do so
Network layer also defines other protocols 6

7. Introducing the Internet Protocol (IP)
Network Layer protocols: Part 1
Name
Full Name
Comments
ICMP
Internetwork Control Message Protocol
Messages that hosts and routers use to manage and control packet forwarding process; used by ping command
ARP
Address Resolution Protocol
Used by LAN hosts to dynamically learn another LAN host’s MAC address
DHCP
Dynamic Host Configuration Protocol
Used by host to dynamically learn IP address (and other information) it can use
DNS
Domain Name System/Service
Allows hosts to use names instead of IP address; needs DNS server to translate name into corresponding IP address (required by IP routing process)
Other TCP/IP Network Layer Protocols 7
Table 8-1

8. Introducing the Internet Protocol (IP)
Network Layer protocols: Part 2
Name
Full Name
Comments
RIP
Routing Information Protocol
Application that runs on routers so that routers dynamically learn IP routing tables (used to route IP packets correctly); open standard protocol defined in RFC 2453
EIGRP
Enhanced Interior Gateway Routing Protocol
Proprietary routing protocol owned by Cisco Systems
OSPF
Open Shortest Path First
Open source routing protocol defined in RFC 2328
Other TCP/IP Network Layer Protocols 8
Table 8-1

9. Introducing the Internet Protocol (IP)
IP defines many functions that work together with one ultimate goal: To send data from one host to another host through any TCP/IP network.
Most important functions include:
Creating end-to-end physical paths through TCP/IP network by interconnecting physical networks (LANs and WANs) using routers
Identifying individual hosts and groups of hosts using IP addressing
Routing (forwarding) IP packets to correct destination host
Example of a Post Office Sorting a Letter Sent to Hollywood, California 9
Figure 8-4

10. Introducing the Internet Protocol (IP)
IPv4 Addresses
32 bits
Expressed in binary and dotted decimal forms
IPv4 Header Format and Fields 10
Figure 8-8

11. Introducing the Internet Protocol (IP)
Converting binary IP address to dotted decimal
Separate 32 bits into 4 groups of 8 bits each
Do binary-to-decimal conversion of each 8-bit number (each decimal value between 0 and 255)
Put period (dot) between each decimal number
Generic View of Converting from Binary IP Address to DDN Format 11
Figure 8-9

12. Introducing the Internet Protocol (IP)
Example: Converting binary IP address to dotted decimal
Converting Binary IP Address to DDN 12
Figure 8-10

13. Introducing the Internet Protocol (IP): Routing
Routing IP Packets from Source to Destination
IP addressing groups addresses into networks
All addresses with same value in first parts of addresses considered to be in one network
Example: All addresses that begin with 11, 12, 13, 14, or 15 in that particular network
Example IP Address Groupings: All with the Same First Octet in the Same Group 13
Figure 8-11

14. IP Addressing on User LANs: Network Settings
Original IPv4 RFC defined way to group IPv4 addresses using IP address classes (classful IP addressing)
Every possible IPv4 address falls into class
First Octet
Class
Purpose A
Reserved
Unicast addresses, in class A networks
127
Reserved for loopback testing B
Unicast addresses, in class B networks C
Unicast addresses, in class C networks D
Multicast addresses; not used as unicast IP addresses E
Experimental; not used as unicast IP addresses
Summary of IPv4 Address Classes Based on First Octet Values 14
Table 8-2

15. IP Addressing on User LANs: Network Settings
Class A includes lower half of IPv4 address space: All IPv4 address that begin with first octet between 0 and 127
Network ID
Class A IP Network Concept
Size (Number of Addresses)
All addresses with a first octet equal to 1
> 16,000,000
All addresses with a first octet equal to 2
All addresses with a first octet equal to 3
All addresses with a first octet equal to 4 …
Etc….
All addresses with a first octet equal to 126
Example Class A Networks 15
Table 8-3

16. IP Addressing on User LANs: Network Settings
Class B includes ¼ of IPv4 address space with first octet value from 128 – 191
Includes medium number (216) of medium sized IP networks for approximately 65,000 hosts per network
Network ID
Concept
Size (Number of Addresses)
All with a first two octets equal to 128.1
> 65,000
All with a first two octets equal to 128.2
All with a first two octets equal to 128.3
All with a first two octets equal to
All with a first two octets equal to
All with a first two octets equal to
Example Class B Networks 16
Table 8-4

17. IP Addressing on User LANs: Network Settings
Class C includes 1/8th of IPv4 address space with first octet between 192 and 223
Large number of small IP networks: over 2,000,000 IP networks, each with 256 IP addresses each
Network ID
Concept
Size (Number of Addresses)
All with a first three octets equal to
254
All with a first three octets equal to
All with a first three octets equal to
All with a first three octets equal to
All with a first three octets equal to
All with a first three octets equal to
Example Class C Networks 17
Table 8-5

18. IP Addressing on User LANs: Network Settings
LAN IP address classes summary
Summary of How Class Rules Break Down the IPv4 Address Space 18
Figure 8-20

19. IP Addressing on User LANs: Network Settings
Private addresses: Classful IP networks reserved for enterprises to use in their network designs
Can only be used on local LAN; can’t be routed through WAN (non-routable)
Not regulated by agencies such as ARIN or ICANN
Network ID
Concept
Size (Number of Addresses)
10.x.x.x
Class A Private IP addressing space
Over 16,000,000 networks of over 16,000,000 IPs each
x.x –
x.x
Class B Private IP addressing space
Over 65,000 networks of over >65,000 IPs each
x.x
Class C Private IP addressing space
Over 65,000 networks of 256 IPs each 19

20. IP Addressing on User LANs: Network Settings
Static IP address assignment: Manually configured
Static IP Address Assignment on Mac OS X 20
Figure 8-21

21. DNS Domain Name System/Service (DNS): Mapping names to IP addresses
Users use names; IP routing uses numbers
DNS translates name into corresponding IP address
DNS client sends DNS Request message
DNS server returns DNS Reply
Following the steps in the Figure:
The user at PC11 wants to connect to “Server1”, but PC11 does not know Server1’s IP address. So, PC11 sends a DNS Request to the DNS Server.
The DNS Server finds that “Server1” is “ ” per its list, so it sends a DNS Reply back to PC11 with that information.
PC11 can now send a packet with destination IP address to Server1.
The figure shows how DNS works in one company, but it also works worldwide, as discussed in Chapter 9, “The Internet
DNS Name Resolution Request, Reply, and Packet to Server1 IP Address 21
Figure 8-14

22. Internet Protocol (IP): Other Protocols
Layer 3 - Network
IP with its Support Protocols 22
Figure 8-15

23. IP Addressing on User LANs: Network Settings
Most host OS’s allow static configuration of several network settings
Host IP Settings 23
Figure 8-22

24. IP Addressing on User LANs: Network Settings
Dynamic Host Configuration Protocol (DHCP) defines way hosts can lease IP address from DHCP network server so does not have to be configured statically
Operates on client-server concept
DHCP protocol defined by set of RFCs
Sample Network for DHCP Discussions 24
Figure 8-23

25. IP Routing with Focus on Layer 3
Router must have IP routing table with useful entries to route IP packets.
Routing table may list multiple routes.
Each IP route identifies network, as well as other information about how to send packets to that network.
Routers look at incoming packet’s destination IP address and compare it to list of network IDs in its routing table to determine where to send packet to destination. 25

26. IP Routing with Focus on Layer 3
Finding a classful network ID based on IP address
Five Classful Networks in a Small Corporate Network 26
Figure 8-28

27. IP Routing with Focus on Layer 3
Each route in routing table lists:
Information about how to match IP packets
Forwarding instructions that tell router where to forward packets to (e.g., next router)
Example: R1’s IP routing table shows five network IDs so it knows routes to all five networks
R1 Routing Table with Routes for Five Classful Networks 27
Figure 8-29

28. IP Routing with Focus on Layer 3: Subnetting
Classful IP networks and wasted IP addresses
Subnetting: Process of subdividing network to create smaller groups of consecutive IP addresses
Subnets (subdivided networks): Smaller groups of addresses
Numbers of Classful Networks, and Their Sizes 28
Figure 8-32

29. IP Routing with Focus on Layer 3: Subnetting
Example: Several subnets created by subnetting network
Each subnet has subnet/network ID
Subdividing (Subnetting) Class A Network 29
Figure 8-33

30. IP Routing with Focus on Layer 3: Subnetting
Example continued: IP addresses and networks replaced with five subnets of network
Sample Corporate Network Using Subnets of Network 30
Figure 8-34

31. IP Routing with Focus on Layer 3: Subnetting
Classful networks have default subnet mask based on each class
Class A: (8 bits)
Class B: (16 bits)
Class C: (24 bits)
If subnet mask anything other than default, then subnetting being used
Routing Logic with Subnets and Masks 31
Figure 8-35

32. IP Routing with Focus on Layer 3: Subnetting
How to calculate subnets
Determine network class (A, B, or C)
Determine EITHER number of hosts needed for each subnet OR how many subnets needed
Determine how many bits needed to provide correct number of hosts/subnets; last subnet is NOT usable
Calculate IPs for each subnet; first IP identifies subnet (Network ID) and last IP identifies broadcast address
Determine subnet mask (total number of bits for network/subnet ID) 32

33. IP Routing with Layer 1, 2, and 3 Interactions
PC encapsulating IP packet into Ethernet frame
Sending bits over LAN cable into network
Encapsulation Review: Data Link Layer 33
Figure 8-39

34. IP Routing with Layer 1, 2, and 3 Interactions
De-encapsulation: On the destination side
Following the de-encapsulation steps in the Figure:
Server S1 physically receives the bits in this frame (layer 1).
Server S1 processes the Ethernet header and trailer, and eventually discards them (layer 2).
Server S1 processes the IP header, and eventually discards it (layer 3).
Server S1 processes the TCP header, and eventually discards it (layer 4).
Server S1 processes the HTTP message (layer 7).
De-encapsulation on a Receiving Host (S1) 34
Figure 8-40

35. IP Routing with Layer 1, 2, and 3 Interactions
To learn destination MAC address, sending device uses Address Resolution Protocol (ARP) and info in ARP table
Address
Short Answer
Long Answer
Source MAC
On NIC
Given to Ethernet NIC by manufacturer; sending host can find MAC on NIC hardware.
Source IP
Configuration
Either through static configuration or DHCP
Destination MAC
ARP
From its ARP table, or if not found, by using ARP protocol and sending ARP Request and waiting for ARP Reply from destination
Destination IP
User
Either typed or clicked by user
How a Sending IP Host Knows What Addresses to Use 35
Table 8-9

36. Summary, This Chapter…
Described the main functions of the TCP/IP network layer in regards to its focus on either physical or logical functions, and the focus on the network or endpoint hosts.
Listed three major functions defined by IP.
Listed common TCP/IP network layer functions in addition to IP.
Examined a figure of an Enterprise TCP/IP network and determine where IP address groups (IP networks or subnets) would be needed. 36

37. Assignments and Lab Unit 8 Assignment 1: Calculating Subnets
Unit 8 Assignment 2: Networking Protocols Review
Lab 8.1: IP Addressing and Classes
Lab 8.2: Assigning Static IP Addresses
Lab 8.3: Routing Tables
Lab 8.4: SOHO Planning
Unit 8 Research Project 1: Chapter 9 Mind Maps

38. Unit 8 Lab Complete all Labs in Chapter 8 of the lab book.
Lab should be completed in class.
Uncompleted Lab must be submitted in the next class.