8.2.1.5 laboratory – Designing and Implementing a VLSM Addressing plan Answers

Lab – Designing and Implementing a VLSM Addressing plan (Answers Version)

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You are watching: 8.2.1.5 lab - designing and implementing a vlsm addressing scheme

Topology

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Objectives

Part 1: study Network RequirementsPart 2: style the VLSM deal with SchemePart 3: Cable and also Configure the IPv4 Network

Background / Scenario

Variable length Subnet Mask (VLSM) to be designed to protect against wasting IP addresses. Through VLSM, a network is subnetted and then re-subnetted. This process can be repeated multiple time to produce subnets of various sizes based on the number of hosts compelled in each subnet. Effective use that VLSM requires attend to planning.

In this lab, use the 172.16.128.0/17 network address to construct an deal with scheme for the network shown in the topology diagram. VLSM is provided to fulfill the IPv4 addressing requirements. ~ you have actually designed the VLSM resolve scheme, you will configure the interfaces on the routers with the suitable IP address information.

Note: The routers provided with CCNA manual labs are Cisco 1941 combined Services Routers (ISRs) with Cisco IOS release 15.2(4)M3 (universalk9 image). Other routers and also Cisco IOS versions can be used. Relying on the model and Cisco IOS version, the commands available and output produced could vary from what is shown in the labs. Describe the Router Interface review Table at the finish of this lab for the correct interface identifiers.

Note: Make sure that the routers have been erased and have no startup configurations. If you room unsure, contact your instructor.

Answers Note: refer to the answers Lab hands-on for the actions to initialize and reload devices.

This lab have the right to be performed in multiple sessions if time is an issue. Components 1 and 2 are file based and can it is in assigned as homework. Part 3 is Hands-on and also requires laboratory equipment.

It is worth noting come the college student that as a network administrator, you would certainly not have actually a single network through over 1000 hosts. You would certainly break this down further in a manufacturing network.

Required Resources

3 routers (Cisco 1941 through Cisco IOS software, relax 15.2(4)M3 universal image or comparable)1 computer (with terminal emulation program, such together Tera Term, to configure routers)Console cable to configure the Cisco IOS gadgets via the console portsEthernet (optional) and also serial cables, as displayed in the topologyWindows Calculator (optional)

Part 1: study Network Requirements

In component 1, you will examine the network demands to develop a VLSM deal with scheme for the network shown in the topology diagram using the 172.16.128.0/17 network address.

Step 1: determine how many host addresses and subnets space available.

How plenty of host addresses are available in a /17 network? ________ 32,766

What is the total number of host addresses required in the topology diagram? ________ 31,506

How numerous subnets are essential in the network topology? ______ 9

Step 2: recognize the largest subnet.

What is the subnet summary (e.g. BR1 G0/1 LAN or BR1-HQ WAN link)? ___________________ HQ G0/0 LAN

How countless IP addresses are compelled in the biggest subnet? __________ 16,000

What subnet mask have the right to support that countless host addresses?

_____________________ /18 or 255.255.192.0

How many total host addresses can that subnet mask support? _________ 16,382

Can friend subnet the 172.16.128.0/17 network deal with to support this subnet? _____ yes

What are the 2 network addresses the would an outcome from this subnetting?

_____________________ 172.16.128.0/18

_____________________ 172.16.192.0/18

Use the very first network address for this subnet.

Step 3: determine the 2nd largest subnet.

What is the subnet description? _____________________________ HQ G0/1 LAN

How plenty of IP addresses are forced for the second largest subnet? ______ 8,000

What subnet mask deserve to support that countless host addresses?

___________________ /19 or 255.255.224.0

How many total host addresses have the right to that subnet mask support? __________ 8,190

Can girlfriend subnet the continuing to be subnet again and still support this subnet? ______ yes

What space the 2 network addresses the would result from this subnetting?

_____________________ 172.16.192.0/19

_____________________ 172.16.224.0/19

Use the an initial network resolve for this subnet.

Step 4: identify the next biggest subnet.

What is the subnet description? _____________________________ BR1 G0/1 LAN

How plenty of IP addresses are forced for the next largest subnet? ______ 4,000

What subnet mask can support that many host addresses?

___________________ /20 or 255.255.240.0

How many total host addresses have the right to that subnet mask support? __________ 4,094

Can friend subnet the staying subnet again and still support this subnet? ______ yes

What space the two network addresses the would result from this subnetting?

_____________________ 172.16.224.0/20

_____________________ 172.16.240.0/20

Use the an initial network address for this subnet.

Step 5: identify the next largest subnet.

What is the subnet description? _____________________________ BR1 G0/0 LAN

How plenty of IP addresses are compelled for the next largest subnet? ______ 2,000

What subnet mask deserve to support that countless host addresses?

___________________ /21 or 255.255.248.0

How many complete host addresses have the right to that subnet mask support? __________ 2,046

Can girlfriend subnet the remaining subnet again and also still support this subnet? ______ yes

What room the 2 network addresses that would an outcome from this subnetting?

_____________________ 172.16.240.0/21

_____________________ 172.16.248.0/21

Use the first network address for this subnet.

Step 6: determine the next biggest subnet.

What is the subnet description? _____________________________ BR2 G0/1 LAN

How countless IP addresses are forced for the next biggest subnet? ______ 1,000

What subnet mask deserve to support that countless host addresses?

___________________ /22 or 255.255.252.0

How many complete host addresses can that subnet mask support? __________ 1,022

Can you subnet the continuing to be subnet again and still assistance this subnet? ______ yes

What space the two network addresses the would result from this subnetting?

_____________________ 172.16.248.0/22

_____________________ 172.16.252.0/22

Use the an initial network address for this subnet.

Step 7: identify the next largest subnet.

What is the subnet description? _____________________________ BR2 G0/0 LAN

How countless IP addresses are forced for the next biggest subnet? ______ 500

What subnet mask have the right to support that numerous host addresses?

___________________ /23 or 255.255.254.0

How many complete host addresses have the right to that subnet mask support? __________ 510

Can girlfriend subnet the remaining subnet again and also still support this subnet? ______ yes

What are the two network addresses the would result from this subnetting?

_____________________ 172.16.252.0/23

_____________________ 172.16.254.0/23

Use the first network attend to for this subnet.

Step 8: recognize the subnets required to assistance the serial links.

How numerous host addresses are forced for every serial subnet link? ______ 2

What subnet mask can support that many host addresses?

___________________ /30 or 255.255.255.252

Continue subnetting the very first subnet the each new subnet until you have four /30 subnets. Write the very first three network addresses of this /30 subnets below.___________________ 172.16.254.0/30___________________ 172.16.254.4/30___________________ 172.16.254.8/30Enter the subnet descriptions because that these 3 subnets below.____________________________ HQ – BR1 Serial Link____________________________ HQ – BR2 Serial Link____________________________ BR1 – BR2 Serial Link

Part 2: architecture the VLSM attend to Scheme

Step 1: calculation the subnet information.

Use the details that you acquired in component 1 to to fill in the adhering to table.

Subnet DescriptionNumber of master NeededNetwork address /CIDRFirst host AddressBroadcast Address
HQ G0/016,000172.16.128.0/18172.16.128.1172.16.191.255
HQ G0/18,000172.16.192.0/19172.16.192.1172.16.223.255
BR1 G0/14,000172.16.224.0/20172.16.224.1172.16.239.255
BR1 G0/02,000172.16.240.0/21172.16.240.1172.16.247.255
BR2 G0/11,000172.16.248.0/22172.16.248.1172.16.251.255
BR2 G0/0500172.16.252.0/23172.16.252.1172.16.253.255
HQ S0/0/0 – BR1 S0/0/02172.16.254.0/30172.16.254.1172.16.254.3
HQ S0/0/1 – BR2 S0/0/12172.16.254.4/30172.16.254.5172.16.254.7
BR1 S0/0/1 – BR2 S0/0/02172.16.254.8/30172.16.254.9172.168.254.11
Step 2: complete the device interface attend to table.

Assign the first host resolve in the subnet come the Ethernet interfaces. HQ should be provided the an initial host address on the Serial links to BR1 and BR2. BR1 need to be provided the an initial host attend to for the serial attach to BR2.

DeviceInterfaceIP AddressSubnet MaskDevice Interface
HQG0/0172.16.128.1255.255.192.016,000 host LAN
G0/1172.16.192.1255.255.224.08,000 host LAN
S0/0/0172.16.254.1255.255.255.252BR1 S0/0/0
S0/0/1172.16.254.5255.255.255.252BR2 S0/0/1
BR1G0/0172.16.240.1255.255.248.02,000 host LAN
G0/1172.16.224.1255.255.240.04,000 hold LAN
S0/0/0172.16.254.2255.255.255.252HQ S0/0/0
S0/0/1172.16.254.9255.255.255.252BR2 S0/0/0
BR2G0/0172.16.252.1255.255.254.0500 hold LAN
G0/1172.16.248.1255.255.252.01,000 organize LAN
S0/0/0172.16.254.10255.255.255.252BR1 S0/0/1
S0/0/1172.16.254.6255.255.255.252HQ S0/0/1

Part 3: Cable and Configure the IPv4 Network

In component 3, you will cable the network topology and configure the three routers using the VLSM resolve scheme that you emerged in component 2.

Step 1: Cable the network as displayed in the topology.Step 2: Configure an easy settings on every router.Assign the an equipment name to the router.Disable DNS lookup to prevent the router indigenous attempting to analyze incorrectly entered commands as though they were hostnames.Assign class as the privileged EXEC encrypted password.Assign cisco as the console password and permit login.Assign cisco together the VTY password and enable login.Encrypt the clear text passwords.Create a banner that will certainly warn anyone accessing the maker that unauthorized accessibility is prohibited.Step 3: Configure the interfaces on each router.Assign an IP resolve and subnet mask come each user interface using the table the you completed in part 2.Configure an interface description for each interface.Set the clocking rate on all DCE serial interfaces to 128000.HQ(config-if)# clock rate 128000Activate the interfaces.Step 4: conserve the configuration on every devices.Step 5: check Connectivity.From HQ, ping BR1’s S0/0/0 interface address.From HQ, ping BR2’s S0/0/1 user interface address.From BR1, ping BR2’s S0/0/0 user interface address.Troubleshoot connectivity issues if pings were not successful.

Note: Pings to the GigabitEthernet interfaces on other routers will certainly not it is in successful. The LANs identified for the GigabitEthernet interfaces are simulated. Since no tools are enclosed to these LANs they will certainly be in down/down state. A routing protocol requirements to it is in in place for other gadgets to be mindful of those subnets. The GigabitEthernet interfaces also need to be in an up/up state before a routing protocol can add the subnets to the routing table. These interfaces will continue to be in a down/down state until a maker is associated to the other finish of the Ethernet interface cable. The emphasis of this laboratory is top top VLSM and configuring the interfaces.

Reflection

Can you think that a shortcut for calculating the network addresses of continuous /30 subnets?

____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

Answers might vary. A /30 network has actually 4 resolve spaces: the network address, 2 hold addresses, and a broadcast address. Another an approach for obtaining the next /30 network resolve would it is in to take the network deal with of the previous /30 network and add 4 to the last octet.

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Router Interface review Table

Router interface Summary
Router ModelEthernet interface #1Ethernet interface #2Serial interface #1Serial user interface #2
1800Fast Ethernet 0/0 (F0/0)Fast Ethernet 0/1 (F0/1)Serial 0/0/0 (S0/0/0)Serial 0/0/1 (S0/0/1)
1900Gigabit Ethernet 0/0 (G0/0)Gigabit Ethernet 0/1 (G0/1)Serial 0/0/0 (S0/0/0)Serial 0/0/1 (S0/0/1)
2801Fast Ethernet 0/0 (F0/0)Fast Ethernet 0/1 (F0/1)Serial 0/1/0 (S0/1/0)Serial 0/1/1 (S0/1/1)
2811Fast Ethernet 0/0 (F0/0)Fast Ethernet 0/1 (F0/1)Serial 0/0/0 (S0/0/0)Serial 0/0/1 (S0/0/1)
2900Gigabit Ethernet 0/0 (G0/0)Gigabit Ethernet 0/1 (G0/1)Serial 0/0/0 (S0/0/0)Serial 0/0/1 (S0/0/1)
Note: To uncover out exactly how the router is configured, look in ~ the interfaces to identify the type of router and also how many interfaces the router has. There is no means to effectively list all the combine of configurations because that each router class. This table includes identifiers because that the possible combinations of Ethernet and Serial interfaces in the device. The table does no include any kind of other type of interface, also though a certain router might contain one. An instance of this could be an ISDN BRI interface. The cable in parenthesis is the legit abbreviation that deserve to be offered in Cisco IOS commands to stand for the interface.

Device Configs

Router BR1 (Final Configuration)

BR1#sh run