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

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.

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

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

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

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

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

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

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

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

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

Introducing the Internet Protocol (IP) Example: Converting binary IP address to dotted decimal Converting Binary IP Address to DDN 10.1.2.3 12 Figure 8-10

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

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 1 - 126 Unicast addresses, in class A networks 127 Reserved for loopback testing 128 - 191 B Unicast addresses, in class B networks 192 - 223 C Unicast addresses, in class C networks 224 - 239 D Multicast addresses; not used as unicast IP addresses 240 - 255 E Experimental; not used as unicast IP addresses Summary of IPv4 Address Classes Based on First Octet Values 14 Table 8-2

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) 1.0.0.0 All addresses with a first octet equal to 1 > 16,000,000 2.0.0.0 All addresses with a first octet equal to 2 3.0.0.0 All addresses with a first octet equal to 3 4.0.0.0 All addresses with a first octet equal to 4 … Etc…. 126.0.0.0 All addresses with a first octet equal to 126 Example Class A Networks 15 Table 8-3

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) 128.1.0.0 All with a first two octets equal to 128.1 > 65,000 128.2.0.0 All with a first two octets equal to 128.2 128.3.0.0 All with a first two octets equal to 128.3 150.48.0.0 All with a first two octets equal to 150.48 180.255.0.0 All with a first two octets equal to 180.255 191.200.0.0 All with a first two octets equal to 191.200 Example Class B Networks 16 Table 8-4

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) 192.1.1.0 All with a first three octets equal to 192.1.1 254 192.1.2.0 All with a first three octets equal to 192.1.2 192.1.3.0 All with a first three octets equal to 192.1.3 200.200.200.0 All with a first three octets equal to 200.200.200 220.255.0.0 All with a first three octets equal to 220.255.0 223.1.1.0 All with a first three octets equal to 123.1.1 Example Class C Networks 17 Table 8-5

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

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 172.16.x.x – 172.31.x.x Class B Private IP addressing space Over 65,000 networks of over >65,000 IPs each 192.168.x.x Class C Private IP addressing space Over 65,000 networks of 256 IPs each 19

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

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 “10.1.2.3” 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 10.1.2.3 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

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

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

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

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

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

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

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

IP Routing with Focus on Layer 3: Subnetting Example: Several subnets created by subnetting network 10.0.0.0 Each subnet has subnet/network ID Subdividing (Subnetting) Class A Network 10.0.0.0 29 Figure 8-33

IP Routing with Focus on Layer 3: Subnetting Example continued: IP addresses and networks replaced with five subnets of network 10.0.0.0 Sample Corporate Network Using Subnets of Network 10.0.0.0 30 Figure 8-34

IP Routing with Focus on Layer 3: Subnetting Classful networks have default subnet mask based on each class Class A: 255.0.0.0 (8 bits) Class B: 255.255.0.0 (16 bits) Class C: 255.255.255.0 (24 bits) If subnet mask anything other than default, then subnetting being used Routing Logic with Subnets and Masks 31 Figure 8-35

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

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

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

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

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

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

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.