Chapter 9 - Reading Organizer 5.0 Done

Name: Samuel Lopez Jr. Date ________________

Chapter 9 Student Version Chapter 9 Objectives:       

Explain why routing is necessary for hosts on different networks to communicate. Describe IP as a communication protocol used to identify a single device on a network. Given a network and a subnet mask, calculate the number of host addresses available. Calculate the necessary subnet mask in order to accommodate the requirements of a network. Describe the benefits of variable length subnet masking (VLSM) Explain how IPv6 address assignments are implemented in a business network. After completing this Reading Organizer, complete the practice Quiz on Netspace.

9.1 Subnetting an IPv4 Network 9.1.1.1. Explain how flat network design operates. This type of configuration is known as a flat network design. In a small network, with a limited number of devices, a flat network design is not problematic. However, as the network grows, this type of configuration can create major issues. 9.1.1.1. Define subnetting. The process of segmenting a network, by dividing it into multiple smaller network spaces 9.1.1.2. What device is required to forward traffic between different networks? A router is necessary for devices on different networks to communicate 9.1.2.1. The address plan includes: a. deciding the needs for each subnet in terms of size b. how many hosts per subnet c. how host addresses will be assigned d. which hosts will require static IP addresses e. which hosts can use DHCP for obtaining their addressing information. 9.1.2.1. What are the three private IP addresses ranges? a. 10.0.0.0 with a subnet mask of 255.0.0.0 1 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

b. 172.16.0.0 with a subnet mask of 255.240.0.0 c. 192.168.0.0 with a subnet mask of 255.255.0.0 9.1.2.1. Who typically allocates public IP addresses? Public addresses used to connect to the Internet are typically allocated from a service provider 9.1.2.2. Two very important factors that will lead to the determination of which private address block is required, are: a. the number of subnets required b. the maximum number of hosts needed per subnet 9.1.3.1. Where is the only place you can borrow bits from? Bits can only be borrowed from the host portion of the address 9.1.3.2. Explain the guidelines for subnets: a. Network address – All 0 bits in the host portion of the address.

b. First host address – All 0 bits plus a right-most 1 bit in the host portion of the address.

c. Last host address – All 1 bits plus a right-most 0 bit in the host portion of the address.

D. Broadcast address – All 1 bits in the host portion of the address.

9.1.3.2. What command would you use to give a Gigabit interface the IP address and subnet mask 192.168.1.1 255.255.255.0? R1(config)#interface gigabitethernet 0/0 R1(config-if)#ip address 192.168.1.129 255.255.255.128 9.1.3.3. What is the formula for calculating the number of subnets? 2^n (where n = the number of bits borrowed) 2 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

9.1.3.6. Enter the correct network address in binary and decimal format. Use 9.1.3.6 to practice.

9.1.3.7. How many usable hosts are available with this network? Use 9.1.3.7 to practice.

9.1.3.8. Define the range of hosts, the broadcast address and the next network address in decimal format. Use 9.1.3.8 to practice.

9.1.3.9. Enter the binary representation of the subnet mask in the octet fields provided. Use 9.1.3.9 to practice.

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Robb Jones

Frederick County Career & Tech Center, MD

9.1.3.13. Enter the network address in binary and decimal format in the octet fields. Use 9.1.3.13 to practice.

9.1.3.14. How many usable hosts are available with this network? Use 9.1.3.14 to practice.

9.1.3.15. Define the range of hosts, the broadcast address and the next network address in decimal format. Use 9.1.3.15 to practice.

4 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

5 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

9.1.4.1. There are two considerations when planning subnets. These are: a. the number of host addresses required for each network

b. the number of individual subnets needed

9.1.4.1. What is the key to determine the number of subnets and hosts needed in a network? The key is to balance the number of subnets needed and the number of hosts required for the largest subnet. The more bits borrowed to create additional subnets means fewer hosts available per subnet. 9.1.4.321. How many addresses are needed for point-to-point WAN links? Some networks, such as point-to-point WAN links, require only two hosts. 9.1.5.1. What was subnetting a subnet, or using Variable Length Subnet Mask (VLSM), was designed to avoid? Subnetting a subnet, or using Variable Length Subnet Mask (VLSM), was designed to avoid wasting addresses. 9.1.5.2. Traditional subnetting creates subnets of equal size. Each subnet in a traditional scheme uses the same subnet mask. What does VLSM allow? VLSM allows a network space to be divided in unequal parts. With VLSM the subnet mask will vary depending on how many bits have been borrowed for a particular subnet, thus the “variable” part of the VLSM. 9.1.5.3. When the number of needed host addresses is known, what formula is used to determine the hosts? 2^n-2 (where n equals the number of host bits remaining) can be used

6 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

9.2 Addressing Schemes 9.2.1.1. There are three primary considerations when planning address allocation. List and explain each. a. Preventing Duplication of Addresses - Each host in an internetwork must have a unique address. Without the proper planning and documentation, an address could be assigned to more than one host, resulting in access issues for both hosts. b. Providing and Controlling Access - Some hosts, such as servers, provide resources to internal hosts as well as to external hosts. The Layer 3 address assigned to a server can be used to control access to that server. If, however, the address is randomly assigned and not well documented, controlling access is more difficult. c. Monitoring Security and Performance - Similarly, the security and performance of network hosts and the network as a whole must be monitored. As part of the monitoring process, network traffic is examined for addresses that are generating or receiving excessive packets. If there is proper planning and documentation of the network addressing, problematic network devices can be easily found. 9.2.1.1. Within a network, there are different types of devices, including: a. End user clients b. Servers and peripherals c. Hosts that are accessible from the Internet d. Intermediary devices e. Gateway

9.3 Design Considerations for IPv6 9.3.1.1. An IPv6 address space is not subnetted to conserve addresses. Why is it subnetted? Rather, it is subnetted to support hierarchical, logical design of the network. 9.3.1.1. An IPv6 address block with a /48 prefix has 16 bits for subnet ID. How many addresses are available using the 16 bit subnet ID? Subnetting using the 16 bit subnet ID yields a possible 65,536 /64 subnets and does not require borrowing any bits from the interface ID, or host portion of the address. 9.3.1.1. How many bits are borrowed from the interface ID in this scenario? 64 9.3.1.1. How many addresses are available in each IPv6 /64 subnet? Quintillion 9.3.1.3. In IPv4 you can borrow bits from the host portion of an address Where can you borrow bits from in IPv6 to create additional IPv6 subnets? 7 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD

Similar to borrowing bits from the host portion of an IPv4 address, with IPv6 bits can be borrowed from the interface ID to create additional IPv6 subnets. This is typically done for security reasons to create fewer hosts per subnet and not necessarily to create additional subnets. 9.3.1.3. Explain where are bit borrowed in IPv6? With IPv6 bits can be borrowed from the interface ID to create additional IPv6 subnets 9.3.1.3. When extending the subnet ID by borrowing bits from the interface ID, the best practice is to subnet on a nibble boundary. 9.3.1.3. What is a nibble? A nibble is 4 bits or one hexadecimal digit. 9.3.1.3. Subnetting on nibble boundaries means only using nibble aligned subnet masks. Starting at /64, the nibble aligned subnet masks are: a. /68 b. /72 c. /76 d. /80 e. /84 f. /88 g. /92 9.3.1.3. It is possible to subnet within a nibble boundary, within a hexadecimal digit, but it is not recommended or even necessary. Explain why. Subnetting within a nibble takes away the advantage easily determining the prefix from the interface ID. For example, if a /66 prefix length is used, the first two bits would be part of the subnet ID and the second two bits would be part of the interface ID.

8 Chapter 8

Robb Jones

Frederick County Career & Tech Center, MD