|
Welcome to CAVI, the Cisco Academy for the Vision Impaired. Course Fees Linux Wiki HTML Wiki Documentation Index PmWiki FAQ |
Main /
Chapter 9 - Subnetting IP Networks9.0 Subnetting IP Networks9.0.1 Introduction >9.0.1.1 IntroductionUpon completion of this chapter you will be able to:
9.0.1 Introduction >9.0.1.2 Activity - Call Me!The figure on this page shows that an IPv6 address is split into 3 parts.
The description given for this figure is "IP network addresses can be structured to represent smaller groups of numbers..." 9.1.1 Network Segmentation >9.1.1.1 Reasons for SubnettingThe figure on this page shows a router with a LAN connected. A host makes a broadcast and the packet is forwarded to every other device on the LAN as well as the router's LAN interface:
9.1.1 Network Segmentation >9.1.1.2 Communication Between SubnetsThe figure on this page shows 2 routers connected. A router with 2 subnets on network 1 is communicating with a router on network 2. This is demonstrating that a router is required to move traffic from one LAN to another. 9.1.2 IP Subnetting is FUNdamental >9.1.2.1 The PlanThe figure on this page shows 3 LANs, the student LAN, Faculty LAN, and Administrative LAN. The figure has a question mark above it. The description given for this figure is "Planning requires decisions on each subnet in terms of size, the number of hosts per subnet, and how host addresses will be assigned.". 9.1.2 IP Subnetting is FUNdamental >9.1.2.2 The Plan - Address AssignmentThe image on this page shows people collaborating on a plan for subnetting. 9.1.3 Subnetting an IPv4 Network >9.1.3.1 Basic SubnettingFigure 1 on this page shows how an IPv4 address is separated into network portion and host portion. 192.168.1.0/24 Network
The description given for this figure is, "With no host bits borrowed, the host portion of both the network address and mask are all 0 bits.". Figure 2 on this page shows how we can borrow bits from the host portion to make subnets. This figure is borrowing 1 bit and as a result can make 2 subnets. With one bit there are 2 values. The bit can be a zero or a one.
The borrowed bit value is 0 for the Net 0 address:
The borrowed bit value is 1 for the Net 1 address:
Net 0 and Net 1 are 2 subnet The new subnets have the SAME subnet mask:
Figure 3 on this page shows the network ID and broadcast address for each of the two subnets.192.168.1.0/24 network.
Borrowing 1 bit creates 2 subnets with the same mask:
9.1.3 Subnetting an IPv4 Network >9.1.3.2 Subnets in UseFigure 1 on this page shows a router with 2 GigabitEthernet interfaces, G0/0 and G0/1. A LAN is connected to each GigabitEthernet interface:
Figure 2 on this page shows the address range for the 192.168.1.0/25 subnet:
Figure 3 on this page shows the address range for the 192.168.1.128/25 subnet:
Figure 4 on this page shows the network and the CLI of the router. The CLI shows how to configure the IP address for each LAN on the appropriate gigabit interface using the R1(config)#interface gigabitethernet 0/0
Figure 5 on this page shows the IP configuration screen of a PC with the correct addresses:
9.1.3 Subnetting an IPv4 Network >9.1.3.3 Subnetting FormulasFigure 1 on this page shows an IP address with the first three octets in decimal. The fourth octet is in binary with the first bit highlighted indicating that it was borrowed for subnetting. This allows us to make 2 (2 raised to the first power) subnets. Subnets = 2^n (2 to the the power of n)
1 bit was borrowed Figure 2 on this page shows an IP address with the first three octets in decimal. The fourth octet is in binary with the last 7 bits for host addressing. This allows us to make 126 (2 raised to the seventh power minus 2) host addresses. Hosts = 2^n (2 to the the power of n)
7 bits remain in host field 9.1.3 Subnetting an IPv4 Network >9.1.3.4 Creating 4 SubnetsFigure 1 on this page shows an IP address with the first three octets in decimal. The fourth octet is in binary with the first two bits highlighted indicating that they were borrowed for subnetting:
Borrowing 2 bits creates 4 subnets:
All 4 subnets use the same mask:
Figure 2 on this page shows how to calculate the number of hosts on each subnet:
6 bits remain in host field
2^6 = 64 hosts per subnet Figure 3 on this page shows the address range for 192.168.1.0/26 subnet:
Figure 4 on this page shows the address ranges for nets 0-2:
Figure 5 on this page shows a router with 2 LANs and one WAN connected. The CLI is also shown with each interface configured with the appropriate interface address from one of the subnets.: R1(config)#interface gigabitethernet 0/0
9.1.3 Subnetting an IPv4 Network >9.1.3.5 Creating 8 SubnetsFigure 1 on this page shows two routers connected with a serial link, each with two LANs. Figures 2 and 3 on this page show the address ranges for nets 0-7:
Figure 4 on this page shows the subnet allocation for two routers, R1 and R2 connected with a serial link, subnet 192.168.1.64/27 each with two LAN's with the network ID's assigned to corresponding networks: R1 subnet allocation:
R2 subnet allocation:
Figure 5 on this page shows the CLI output from two routers with the configuration from all six interfaces including the IP address and subnet mask: R1: R1(config)#interface gigabitethernet 0/0
R2: R1(config)#interface gigabitethernet 0/0
9.1.3 Subnetting an IPv4 Network >9.1.3.6 Activity - Determining the Network Address - BasicThe figure on this page is an interactive activity that allows the learner to practice converting IP addresses into Network Addresses in binary and then dotted decimal. The learner is given random IP addresses and subnet masks. For each conversion, the learner is asked to enter the correct network address in binary and in decimal format. For example:
9.1.3 Subnetting an IPv4 Network >9.1.3.7 Activity - Calculate the Number of Hosts - BasicThe figure on this page is an interactive activity that allows the learner to practice calculating the number of valid hosts. The learner is given an address and a subnet mask. The learner must determine the number of valid hosts per network. For example:
9.1.3 Subnetting an IPv4 Network >9.1.3.8 Activity - Determining the Valid Addresses for Hosts - BasicThe figure on this page is an interactive activity that allows the learner to practice calculating the network address, first valid host address, last valid host address, and broadcast address. The learner is given the network address and subnet mask and asked to define the range of hosts, the broadcast address, and the next network address. For example:
9.1.3 Subnetting an IPv4 Network >9.1.3.9 Activity - Calculate the Subnet MaskThe figure on this page is an interactive activity that allows the learner to practice converting a subnet mask in dotted decimal into a subnet mask in binary and prefix notation (slash notation). The learner is given a subnet mask in decimal format and asked to determine the binary representation of the subnet mask. The learner is asked to also convert the mask to prefix notation (/x) format. For example:
9.1.3 Subnetting an IPv4 Network >9.1.3.10 Creating 100 Subnets with a /16 prefixThe figure on this page shows that by borrowing 7 host bits from a /16, you can make 128 subnets. These subnets would be a /23:
Borrowing 7 bits creates 128 subnets
9.1.3 Subnetting an IPv4 Network >9.1.3.11 Calculating the HostsFigure 1 on this page shows that with a /23, there are 9 host bits, and two raised to the ninth power minus 2 (or 510) valid hosts: Hosts = 2^n
9 bits remain in host field 2^9 = 512 hosts per subnet Figure 2 on this page shows the address range for the 172.16.0.0/23 subnet:
9.1.3 Subnetting an IPv4 Network >9.1.3.12 Calculating the HostsFigure 1 on this page shows that given a 10.0.0.0/8 network, if you borrow ten host bits for subnetting, you can create two raised to the tenth power (2^10) or 1024 subnets:
Figure 2 on this page shows how to calculate the number of hosts. If you borrow ten bits for subnetting from a /8, you have 18 network bits and therefore 14 host bits. With 14 host bits, you have two raised to the fourteenth power minus two ((2^14)-2) or 16,382 valid hosts on each subnet:
14 bits remain in host field. 2^14 = 16384 hosts per subnet. (2^14)-2 = 16382 valid hosts per subnet. Figure 3 on this page shows the address range for 10.0.0.0/18 subnet:
9.1.3 Subnetting an IPv4 Network >9.1.3.13 Activity - Determining the Network Address - AdvancedThe figure is an interactive activity that allows the learner to practice calculating the network address for more advanced subnetting examples. In this activity you are given the hiost address, subnet mask, host address (in binary format), and subnet mask (in binary format). The learner is asked to enter the network address in binary and decimal formats in the octet fields. For example:
The figure also has the following 3 buttons:
9.1.3 Subnetting an IPv4 Network >9.1.3.14 Activity - Calculating the Number of Hosts - AdvancedThe figure is an interactive activity that allows the learner to practice calculating the number of valid host addresses for more advanced subnetting examples. In this activity, you are given the network address, subnet mask, binary network address, and binary subnet mask. The learner is asked to enter the number of hosts that are available for addressing in the Number of Valid Hosts field.
The figure also has the following 3 buttons:
9.1.3 Subnetting an IPv4 Network >9.1.3.15 Activity – Determining the Valid Addresses for HostsThe figure is an interactive activity that allows the learner to practice calculating the network address, first valid host address, last valid host address, and broadcast address for a given host address and subnet mask for more advanced subnetting examples. In the activity the learner is given the network address and subnet mask. The learner is asked to define the range of hosts, the broadcast address and the next network address and enter the answers in decimal format in the octet fields provided. For example
The figure also has the following 3 buttons:
9.1.4 Determining the Subnet Mask >9.1.4.1 Subnetting Based on Host RequirementsThe animation on this page shows a table that displays the subnet possibilities for the 192.168.1.0 network.
9.1.4 Determining the Subnet Mask >9.1.4.2 Subnetting Network-Based RequirementsThe figure on this page shows a cloud with smaller clouds within. This figure demonstrates subnetting based on organizational structure. The large cloud represents the Corporate Network. The smaller clouds represent:
9.1.4 Determining the Subnet Mask >9.1.4.3 Subnetting to Meet Network RequirementsFigure 1 on this page shows a corporate network divided by department. The host requirements for each department are:
Figure 2 on this page shows how a /22 has ten host bits which allows for 1022 valid hosts.
9.1.4 Determining the Subnet Mask >9.1.4.4 Subnetting to Meet Network Requirements (Cont.)Figure 1 on this page shows the 16 subnets that are formed when creating /26s out of a /22. You can see that by alternating bits 23, 24, 25, and 26 in a logical order, you can easily determine the network IDs for all sixteen subnets.
Figure 2 on this page shows the same table as figure 1 a callout pointing to the 4 subnet bits, which demonstrates how 16 subnets are formed (2^4 = 16 subnets). There is also a callout pointing to the 6 remaining host bits showing that there are 62 valid hosts on each of these subnets (2^6-2 = 62 hosts per subnet). Figure 3 on this page shows how these subnets might be assigned to the departments in a corporate network. Each subnet is the same size.
9.1.4 Determining the Subnet Mask >9.1.4.5- Activity: Determine the Number of Bits to Borrow.The figure on this page is an interactive activity that allows the learner to practice calculating the network address for more advanced subnetting examples. The learner is given the number of hosts that are needed. The learner is then asked to determine the subnet mask that would support the number of hosts as specified and enter the answers in binary, decimal, and prefix notation format in the fields provided.
The figure also has the following 2 buttons:
9.1.4 Determining the Subnet Mask >9.1.4.6: Subnetting Scenario 1Objectives:Part 1: Design an IP Addressing Scheme Part 2: Assign IP Addresses to Network Devices and Verify Connectivity 9.1.4 Determining the Subnet Mask >9.1.4.6: Subnetting Scenario 2Objectives:Part 1: Design an IP Addressing Scheme Part 2: Assign IP Addresses to Network Devices and Verify Connectivity 9.1.4 Determining the Subnet Mask >9.1.4.8: Calculating IPv4 SubnetsSee Lab Descriptions. 9.1.4 Determining the Subnet Mask >9.1.4.9: Subnetting Network TopologiesSee Lab Descriptions. 9.1.4 Determining the Subnet Mask >9.1.4.10: Researching Subnet CalculatorsSee Lab Descriptions. 9.1.5 Benefits of Variable Length Subnet Masking >9.1.5.1 Traditional Subnetting Wastes AddressesFigure 1 on this page shows four routers with different host requirements. Each router is connected to the adjacent router with a WAN link. This shows a need for seven subnets as described in the page notes.
Figure 2 on this page shows that by borrowing three host bits from a /24, we can create 8 subnets. These subnets will be a /27.
Figure 3 on this page shows that with the remaining five bits we will have 30 valid hosts on each of the subnets.
9.1.5 Benefits of Variable Length Subnet Masking >9.1.5.2 Variable Length Subnet Masks (VLSM)Figure 1 on this page shows a pie chart representing a network that has been split into eight equal subnets of 30 hosts each. Figure 2 on this page shows one of the subnets further subnetted to /30s, and each hold 2 valid host addresses. 9.1.5 Benefits of Variable Length Subnet Masking >9.1.5.3 Basic VLSMFigure 1 on this page shows the binary representation of the eight subnets formed by borrowing 3 bits from a /24 making /27s.
Figure 2 on this page shows the binary representation of the eight subnets formed by borrowing 3 bits from a /27 making /30s.
3 more bit borrowed from subnet 7:
9.1.5 Benefits of Variable Length Subnet Masking >9.1.5.4 VLSM in PracticeFigure 1 on this page shows four routers connected with a WAN link.
Figure 1 on this page also shows the CLI configuration commands to configure the interfaces on Router 1 for building A: R1 (config)#interface gigabitethernet 0/0
Figure 2 on this page shows the CLI configuration commands to configure the interfaces on Router 2 for building B: R2 (config)#interface gigabitethernet 0/0
Figure 3 on this page shows the CLI configuration commands to configure the interfaces on Router 3 for building C: R3 (config)#interface gigabitethernet 0/0
Figure 4 on this page shows the CLI configuration commands to configure the interfaces on Router 4 for building D: R4 (config)#interface gigabitethernet 0/0
9.1.5 Benefits of Variable Length Subnet Masking >91.5.5 VLSM ChartFigure 1 on this page shows a chart using basic subnetting to assign equal sized subnets to the LANs and WANs.
Figure 2 on this page shows a chart using VLSM subnetting to assign equal sized (slash twenty sevens) subnets to each of the LAN links and different but equal sized (slash thirties) subnets to each of the WAN links.
9.1.5 Benefits of Variable Length Subnet Masking >9.1.5.6 Activity - Practicing VLSMFigure 1 on this page is an interactive activity that allows the learner to practice regular subnetting by matching the addresses with their subnet description. The following table uses regular subnetting to accommodate the network shown. Match the addresses to the appropriate subnet description.
The Subnet Addresses are:
The figure also has the following 2 buttons:
Figure 2 on this page is an interactive activity that allows the learner to practice subnetting by matching the parts from VLSM subnetting with their description.
The Subnet Addresses are:
The figure also has the following 2 buttons:
9.2 Addressing Schemes9.2.1 Structured Design >9.2.1.1 Planning to Address the NetworkThe figure on this page shows two groupings of computers, printers, and servers. This illustrates that planning before subnetting is important. The description given for this figure is "Network addressing should be based on network segmentation." 9.2.1 Structured Design >9.2.1.2 Assigning Addresses to DevicesThe figure on this page shows a table with a breakdown of IP address assignment based on network design.
9.2.1 Structured Design >9.2.1.3: Lab - Designing and Implementing a Subnetted IPv4 Addressing SchemeSee Lab Descriptions. 9.2.1 Structured Design >9.2.1.4: Lab - Designing and Implementing a VLSM Addressing SchemeSee Lab Descriptions. 9.2.1 Structured Design >9.2.1.5: Packet Tracer - Designing and Implementing a VLSM Addressing SchemeObjectives:Part 1: Examine the Network Requirements Part 2: Design the VLSM Addressing Scheme Part 3: Assign IP Addresses to Devices and Verify Connectivity 9.3 Design Considerations for IPv69.3.1 Subnetting an IPv6 Network >9.3.1.1 Subnetting Using the Subnet IDFigure 1 on this page shows the structure of an IPv6 /48 address block.
The subnet ID in the address block has 65,536 subnets in the range:
to
Figure 2 on this page shows that the 16 bits, represented in hexadecimal, can make 65,536 subnets. These subnets are 0000 through FFFF. Increment Subnet ID to create 65,536 subnets.
9.3.1 Subnetting an IPv6 Network >9.3.1.2 IPv6 Subnet AllocationFigure 1 on this page shows two routers connected by a serial link. Each router has 2 switches attached and each switch has one computer attached.
Figure 2 on this page shows several IPv6 subnet IDs and highlighting 5 which will be used for the networks previously displayed.
Figure 3 on this page shows the previous network topology with the IPv6 subnets assigned to the networks.
Figure 4 on this page shows a router with the CLI showing how to configure each interface with an I.P. version 6 address. @@R1 (config)#interface gigabitethernet 0/0
R1 (config-if)#ipv6 address 2001:db8:acad:1::1/64 R1 (config-if)#exit R1 (config)#interface gigabitethernet 0/1 R1 (config-if)#ipv6 address 2001:db8:acad:2::1/64 R1 (config-if)#exit R1 (config)#interface serial 0/0/0 R1 (config-if)#ipv6 address 2001:db8:acad:3::1/64 R1 (config-if)#end R1#@@ 9.3.1 Subnetting an IPv6 Network >9.3.1.3 Subnetting into the Interface IDThe figure on this page shows the structure of an IPv6 address as a /68. This address borrows 4 more bits (or 1 nibble) from the host addresses. Nibble = 4 bits (1 hexadecimal digit)
Subnet ID extended 1 nibble (4 bits). 9.3.1 Subnetting an IPv6 Network >9.3.1.4: Packet Tracer - Implementing a Subnetted IPv6 Addressing SchemeObjectives:Part 1: Determint the IPv6 Subnets and Addressing Scheme Part 2: Configure the IPv6 Addressing on Routers and PCs and Verify Connectivity 9.4 Summary9.4.1 Summary >9.4.1.1 Activity - Can you call me now?The figure on this page shows a pie chart with 8 equal sections. One of the sections is further broken down into 8 more equal sections. This figure demonstrates how to incorporate VLSM into a network design. Careful planning is required to make best use of an IP addressing scheme. Plan for:
9.4.1 Summary >9.4.1.2: Packet Tracer - Skills Integration Challenge9.4.1 Summary >9.4.1.3 SummaryThe figure on this page shows how to separate a slash twenty into two slash twenty five by changing the twenty fifth bit from a zero to one.
Borrowing 1 bit creates 2 subnets with the same mask.
End of Chapter 9: Subnetting IP Networks. Next - Chapter 10: Application Layer.|| |
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||