SEMESTER 1 Chapter 6 Addressing the Network IPv4 V 4.0

6.1.1 How many bits are the 32 bits source and destination IPv4 addresses? What is the name for the Dotted Decimal decimal representation of the binary IP address called? How many bits are there 8 bits between each “dot”? What are those bits called? Octet Define the network portion a group of hosts that have identical bit patterns of an IP address? in the network address portion of their addresses What is the host portion of Although all 32 bits define the IPv4 host the IP address? address, we have a variable number of bits that are called the host portion of the address What does the number of the number of hosts that we can have within bits assigned to host the network determine? 6.1.2 What is the binary range in 0-255 decimal of a byte? The Binary conversions will be rest of covered in the lab meeting? 6.1 6.2.1 Define a network address. Within the IPv4 address range of a network, the lowest address is reserved for the network address. Define a broadcast address. The broadcast address uses the highest address in the network range. Define a host address. The addresses assigned to the end devices in the network. What is the range where Located between the network and the host addresses assigned? broadcast address. 6.2.1.2 What is assigned to Prefix determine how many bits are in network bits? Do the number of hosts that No can be assigned stay the same when prefix changes? 6.2.2.1 How do you calculate the All host bits are 0 network value? How do you calculate the 1 greater than the network address first host value? How do you calculate the All host bits are turned on broadcast address? How do you calculate the 1 less than the broadcast address last host address? 6.2.2.2 This flash exercise is excellent practice for calculating the different values; you can do this until you have mastered the process. Please try it with prefix values of 24 and over so you have an example to go by. 6.2.3 Define unicast the process of sending a packet from one host to an individual host Define broadcast the process of sending a packet from one host to all hosts in the network Define multicast the process of sending a packet from one host to a selected group of hosts What is another name for a Host address unicast address? 6.2.3.2 How does a host process a it processes the packet as it would a packet to broadcast transmission? its unicast address What is a broadcast the location of special services/devices for transmission used for? which the address is not known or when a host needs to provide information to all the hosts on the network. What are the three Mapping upper layer addresses to lower layer examples of broadcast addresses transmissions? Requesting an address Exchanging routing information by routing protocols When does a host send a When a host needs information, the host broadcast? sends a request, called a query, to the broadcast address How do hosts with the One or more of the hosts with the requested information usually respond information will respond, typically using to the broadcast? unicast. What is a directed A directed broadcast is sent to all hosts on a broadcast? specific network. What is a limited broadcast communication that is limited to the hosts on used for? the local network What forms the boundary Router for a broadcast domain? 6.2.3.3 What is multicast designed conserve the bandwidth of the IPv4 network to do? What are the 4 examples of Video and audio broadcasts multicast transmissions? Routing information exchange by routing protocols Distribution of software News feeds How are multicast The multicast clients use services initiated by a addresses assigned? client program to subscribe to the multicast group. What is the range for 224.0.0.0 to 239.255.255.255 multicast addresses? What is the range for 240.0.0.0 to 255.255.255.254 experimental addresses? 6.2.5.1 List the three private 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8) address blocks? (This is 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12) incredibly important for 192.168.0.0 to 192.168.255.255 (192.168.0.0 / network administrators to 16) know) What happens if a packet It would not be forwarded with a private IP address was sent to the Internet? What is NAT Network to translate private addresses to public Address Translation addresses, hosts on a privately addressed services used for? network can have access to resources across the Internet How does NAT allow a host It allows the host to “borrow” a public IP with a private address to address access the Internet? 6.2.5.2 Excellent practice. This is very important for the test. 6.2.6 What is the range for local- 169.254.0.0 to 169.254.255.255 link addresses? When is a local link address automatically assigned to the local host by the assigned to a device? operating system in environments where no IP configuration is available 6.2.7 What is the first octet range 1-126 of Class A? What is the first octet range 128-191 of Class B? What is the first octet range 192-223 of Class C? What is the first octet range 224-239 of Class D? What is the first octet range 240-255 of Class E? What is the limitation of wasted many addresses, which exhausted the classful routing? availability of IPv4 addresses What is the address system Classless addressing used today called? Why should the allocation of Preventing duplication of addresses addresses inside the Providing and controlling access networks be planned and Monitoring security and performance documented for the purpose of? What are the different End devices for users examples of types of hosts? Servers and peripherals Hosts that are accessible from the Internet Intermediary devices 6.3.1.2 What considerations should Will there be more devices connected to the be used about where network than public addresses allocated by the private IP addresses should network's ISP? be used? Will the devices need to be accessed from outside the local network? If devices that may be assigned private addresses require access to the Internet, is the network capable of providing a Network Address Translation (NAT) service? 6.3.2 Which devices should have printers, servers, and other networking devices static IP addresses that need to be accessible to clients on the assigned? network 6.3.2.2 What does DHCP provide automatic assignment of addressing for an end device? information such as IP address, subnet mask, default gateway, and other configuration information What is the block of Address pool addresses a DHCP server use called? 6.3.3 Which devices should have Servers and printers a static IP address? Why? So hosts can have consistent access What does almost all traffic Intermediary Devices pass through when going between networks? Which IP addresses are Lowest or Highest addresses in the range used for router interfaces? 6.3.4 What is the organization Internet Assigned Numbers Authority (IANA) that assigns IP addresses in the US? 6.3.5 What are the advantages of reliability and speed having a Tier 1 ISP? What is the focus of a Tier 2 focus on business customers ISP? What is the focus of a Tier 3 The focus of these ISPs is the retail and home ISP? markets in a specific locale. 6.3.6 What was the main issue to Creating expanded addressing capabilities be addressed by IPv6? What were the other issues Improved packet handling that were considered when Increased scalability and longevity developing IPv6? QoS mechanisms Integrated security List the added features of 128-bit hierarchical addressing - to expand IPv6. addressing capabilities Header format simplification - to improve packet handling Improved support for extensions and options - for increased scalability/longevity and improved packet handling Flow labeling capability - as QoS mechanisms Authentication and privacy capabilities - to integrate security 6.4.1 How is the subnet mask by placing a binary 1 in each bit position that created? represents the network portion and placing a binary 0 in each bit position that represents the host portion What is true if the octet of All of the octet is network/subnetwork bits. the subnet mask is 255? What is true if the octet of All of the octet is host bits. the subnet mask is 0? 6.4.2 What is the result of the The network address ANDing process? What is the only case in 1 anded with a 1 which ANDing results in a 1? 6.5 We will cover this in class. Good exercises and examples to read through. 6.5.4- Excellent practice 6 exercises, practice these a lot. 6.6.1 What is ping? utility for testing IP connectivity between hosts What happens when the it responds with an ICMP Echo Reply destination host receives an datagram. echo request? What is the address to ping 127.0.0.1 the local host? What does a response from that IP is properly installed on the host the local host tell you? What doesn’t the response an indication that the addresses, masks, or from the local host tell you? gateways are properly configured 6.6.2 What does it tell you if a indicates that the host and the router's ping to the gateway is interface serving as that gateway are both successful? operational on the local network 6.6.3 What does it tell you if a It means that we have verified our host's ping to the remote host is communication on the local network, the successful? operation of the router serving as our gateway, and all other routers that might be in the path between our network and the network of the remote host. 6.6.4 What does the traceroute allows us to observe the path between these utility do? hosts Define Round Trip Time the time a packet takes to reach the remote (RTT). host and for the response from the host to return Define Time to Live (TTL). When a packet enters a router, the TTL field is decremented by 1. When the TTL reaches zero, a router will not forward the packet and the packet is dropped. 6.6.5 What does ICMP provide for ICMP provides control and error messages the TCP/IP protocol stack? and is used by the ping and traceroute utilities. List the 5 ICMP messages Host conformation that may be sent? Unreachable Destination or Service Time exceeded Route redirection Source quench What are the 4 destination 0 = net unreachable unreachable codes listed? 1 = host unreachable 2 = protocol unreachable 3 = port unreachable

You will use the following tables for multiple questions. * 255.255.255.192 (or /26) 0 - 63 64 - 127 128 - 191 192 - 255 (with multiplier of 64)

* 255.255.255.224 (or /27) 0 - 31 32 - 63 64 - 95 96 - 127 128 - 159 160 - 191 192 - 223 224 - 255 (with multiplier of 32)

* 255.255.255.240 (or /28) 0 - 15 16 - 31 32 - 47 48 - 63 64 - 79 80 - 95 96 - 111 112 - 127 And so on (with multiplier of 16)

* 255.255.255.248 (or /29) 0 - 7 8 - 15 16 - 23 24 - 31 32 - 39 40 - 47 48 - 55 56 - 63 And so on (with multiplier of 8) * Which prefix (subnetmask) needed for the following network? (Hint: you need to know the block size.)

- Use the reference table to solve this problem.

* You will be presented a list of IP address and are expected to pick up: - Usable (assignable) host addresses * Study the reference table included above.

- Network IP address * Study the reference table included above.

- Broadcast IP address * Study the reference table included above.

* Network IP address - The IPv4 host address is logically ANDed with its subnet mask to determine the network address to which the host is associated. - At Layer 3, we define a network as a group of hosts that have identical bit patterns in the network address portion of their addresses. - A router uses this address forwarding of packet to a given destination - Network address varies in length - portion of the high-order bits (1) represents the network address.

* Some basic rule about IP address: . Private addresses – There are blocks of addresses that require no Internet access. • 10.0.0.0 to 10.255.255.255 (10.0.0.0 /8) • 172.16.0.0 to 172.31.255.255 (172.16.0.0 /12) • 192.168.0.0 to 192.168.255.255 (192.168.0.0 /16) . If devices that may be assigned private addresses require access to the Internet, a NAT service would allow those devices with private addresses to effectively share the remaining public addresses. . Loopback – The loopback address 127.0.0.1. – You can ping the loopback address to test the configuration of TCP/IP on the local host. – This also covers all addresses in 127.0.0.0 to 127.255.255.255.

* You will be asked to troubleshooting of why is your PC not able to get on the internet. - You need to make sure that the IP address for your PC, your default gateway and router interface are all in the same subnet. - Study the reference table included above. * 255.255.0.0: How many hosts are in this subnet? * 255.255.255.0: How many hosts are in this subnet? * 255.255.254.0: How many hosts are in this subnet? * 255.255.248.0: How many hosts are in this subnet?

* With a static assignment, the network administrator must manually configure the network information for a host . The addresses for these devices should be static. – Addresses for Servers and Peripherals – Addresses for Hosts that are Accessible from Internet – The router or firewall

* IPv6 offers: – 128-bit hierarchical addressing - to expand addressing capabilities – Header format simplification - to improve packet handling – Improved support for extensions and options - for increased scalability/longevity and improved packet handling – Flow labeling capability - as QoS mechanisms – Authentication and privacy capabilities - to integrate security

* IPv6 is not a new Layer 3 protocol – it is a new protocol suite. – New messaging protocol (ICMPv6) – New routing protocols. – don’t pick the answer for faster routing protocol lookup

* Time to Live (TTL) – Traceroute makes use of a function of the TTL field in the Layer 3 header and ICMP Time Exceeded Message. – When a packet enters a router, the TTL field is decremented by 1. When the TTL reaches zero, a router will not forward the packet and the packet is dropped. – In addition to dropping the packet, the router normally sends an ICMP Time Exceeded message addressed to the originating host. This ICMP message will contain the IP address of the router that responded.

* Pinging the Local Loopback . One case is for testing the internal configuration of IP on the local host. . To perform this test, we ping the special reserve address of local loopback (127.0.0.1). . A response from 127.0.0.1 indicates that IP is properly installed on the host. . This response is not, however, an indication that the addresses, masks, or gateways are properly configured. Nor does it indicate anything about the status of the lower layer of the network stack.