11.10.2 Lab – Design and Implement a VLSM Addressing Scheme (Answers)

11.10.2 Lab – Design and Implement a VLSM Addressing Scheme

Topology

Goals

• Half 1: Look at Community Necessities
• Half 2: Design the VLSM Tackle Scheme
• Half 3: Cable and Configure the IPv4 Community

Background / State of affairs

Variable Size Subnet Masks (VLSM) was designed to keep away from losing IP addresses. With VLSM, a community is subnetted after which re-subnetted. This course of will be repeated a number of instances to create subnets of varied sizes based mostly on the variety of hosts required in every subnet. Efficient use of VLSM requires deal with planning.

On this lab, use the 192.168.33.128/25 community deal with to develop an deal with scheme for the community displayed within the topology diagram. VLSM is used to fulfill the IPv4 addressing necessities. After you’ve designed the VLSM deal with scheme, you’ll configure the interfaces on the routers with the suitable IP deal with info. The longer term LANS at BR2 might want to have addresses allotted, however no interfaces will probably be configured right now.

Observe: The routers used with CCNA hands-on labs are Cisco 4221 with Cisco IOS XE Launch 16.9.4 (universalk9 picture). The switches used within the labs are Cisco Catalyst 2960s with Cisco IOS Launch 15.2(2) (lanbasek9 picture). Different routers, switches, and Cisco IOS variations can be utilized. Relying on the mannequin and Cisco IOS model, the instructions out there and the output produced would possibly range from what’s proven within the labs. Consult with the Router Interface Abstract Desk on the finish of the lab for the proper interface identifiers.

Observe: Ensure that the routers have been erased and don’t have any startup configurations. In case you are uncertain, contact your teacher.

Teacher Observe: Consult with the Teacher Lab Handbook for the procedures to initialize and reload gadgets.

This lab will be carried out in a number of periods if time is a matter. Elements 1 and a pair of are paper based mostly and will be assigned as homework. Half 3 is Fingers-on and requires lab tools.

Required Sources

• 2 Routers (Cisco 4221 with Cisco IOS XE Launch 16.9.4 common picture or comparable)
• 2 Switches (Cisco 2960 with Cisco IOS Launch 15.2(2) lanbasek9 picture or comparable)
• 1 PCs (Home windows with terminal emulation program, similar to Tera Time period)
• Console cables to configure the Cisco IOS gadgets by way of the console ports
• Ethernet and serial cables as proven within the topology
• Home windows Calculator (non-obligatory)

Directions

Half 1: Look at Community Necessities

In Half 1, you’ll study the community necessities to develop a VLSM deal with scheme for the community displayed within the topology diagram utilizing the 192.168.33.128/25 community deal with.

Observe: You need to use the Home windows Calculator utility and search the web for an IP subnet calculator to assist together with your calculations.

Step 1: Decide what number of host addresses and subnets can be found.

What number of host addresses can be found in a /25 community?
126

What’s the whole variety of host addresses wanted within the topology diagram?
80

What number of subnets are wanted within the community topology?
6

Step 2: Decide the biggest subnet.

What’s the subnet description (e.g. BR1 LAN or BR1-BR2 hyperlink)?
BR1 LAN

What number of IP addresses are required within the largest subnet?
40

What subnet masks can assist that many host addresses?
/26 or 255.255.255.192

What number of whole host addresses can that subnet masks assist?
62

Are you able to subnet the 192.168.33.128/25 community deal with to assist this subnet?
sure

What are the community addresses that might consequence from this subnetting?

192.168.33.128/26 and 192.168.33.192/26

Use the primary community deal with for this subnet.

Step 3: Decide the second largest subnet.

What’s the subnet description?
BR2 LAN

What number of IP addresses are required for the second largest subnet?
25

What subnet masks can assist that many host addresses?
/27 or 255.255.255.224

What number of whole host addresses can that subnet masks assist?
30

Are you able to subnet the remaining subnet once more and nonetheless assist this subnet?
sure

What are the community addresses that might consequence from this subnetting?

192.168.33.192/27 and 192.168.33.224/27

Use the primary community deal with for this subnet.

Step 4: Decide the third largest subnet.

What’s the subnet description?
BR2 IoT LAN

What number of IP addresses are required for the subsequent largest subnet?
5

What subnet masks can assist that many host addresses?
/29 or 255.255.255.248

What number of whole host addresses can that subnet masks assist?
6

Are you able to subnet the remaining subnet once more and nonetheless assist this subnet?
sure

What are the community addresses that might consequence from this subnetting?
192.168.33.224/29, 192.168.33.232/29, 192.168.33.240/29, and 192.168.33.248/29

Use the primary community deal with for this subnet.
Use the second community deal with for the CCTV LAN.
Use the third community deal with for the HVAC C2 LAN.

Step 5: Decide the fourth largest subnet.

What’s the subnet description?
BR1-BR2 Hyperlink

What number of IP addresses are required for the subsequent largest subnet?
2

What subnet masks can assist that many host addresses?
/30 or 255.255.255.252

What number of whole host addresses can that subnet masks assist?
2

Are you able to subnet the remaining subnet once more and nonetheless assist this subnet?
sure

What are the community addresses that might consequence from this subnetting?
192.168.33.248/30 and 192.168.33.252/30

Use the primary community deal with for this subnet.

Half 2: Design the VLSM Tackle Scheme

Step 1: Calculate the subnet info.

Use the data that you simply obtained in Half 1 to fill within the following desk.

Step 2: Full the system interface deal with desk.

Assign the primary host deal with within the subnet to the Ethernet interfaces. BR1 needs to be assigned the primary host deal with within the BR1-BR2 Hyperlink.

Half 3: Cable and Configure the IPv4 Community

In Half 3, you’ll cable the community to match the topology and configure the three routers utilizing the VLSM deal with scheme that you simply developed in Half 2.

Step 1: Cable the community as proven within the topology.

Step 2: Configure primary settings on every router.

a. Assign the system title to the routers.

router(config)# hostname BR1
router(config)# hostname BR2

b. Disable DNS lookup to stop the routers from making an attempt to translate incorrectly entered instructions as if they have been hostnames.

BR1(config)# no ip area lookup
BR2(config)# no ip area lookup

c. Assign class because the privileged EXEC encrypted password for each routers.

BR1(config)# allow secret class
BR2(config)# allow secret class

d. Assign cisco because the console password and allow login for the routers.

BR1(config)# line con 0
BR1(config-line)# password cisco
BR1(config)# login
BR2(config)# line con 0
BR2(config-line)# password cisco
BR2(config)# login

e. Assign cisco because the VTY password and allow login for the routers.

BR1(config)# line vty 0 4
BR1(config-line)# password cisco
BR1(config-line)# login
BR2(config)# line vty 0 4
BR2(config-line)# password cisco
BR2(config-line)# login

f. Encrypt the plaintext passwords for the routers.

BR1(config)# service password-encryption
BR2(config)# service password-encryption

g. Create a banner that can warn anybody accessing the system that unauthorized entry is prohibited on each routers.

BR1(config)# banner motd $ Unauthorized Entry is Prohibited $
BR2(config)# banner motd $ Unauthorized Entry is Prohibited $

Step 3: Configure the interfaces on every router.

a. Assign an IP deal with and subnet masks to every interface utilizing the desk that you simply accomplished in Half 2.

BR1(config)# interface g0/0/0
BR1(config-if)# ip deal with 192.168.33.249 255.255.255.252
BR1(config-if)# interface g0/0/1
BR1(config-if)# ip deal with 192.168.33.129 255.255.255.192
BR2(config)# interface g0/0/0
BR2(config-if)# ip deal with 192.168.33.250 255.255.255.252
BR2(config-if)# interface g0/0/1
BR2(config-if)# ip deal with 192.168.33.192 255.255.255.224

b. Configure an interface description for every interface.

BR1(config)# interface g0/0/0
BR1(config-if)# description BR1-BR2 Hyperlink
BR1(config-if)# interface g0/0/1
BR1(config-if)# description Related to S1
BR2(config-if)# interface g0/0/0
BR2(config-if)# description BR1-BR2 Hyperlink
BR2(config-if)# interface g0/0/1
BR2(config-if)# description Related to S2

c. Activate the interfaces.

BR1(config)# interface g0/0/0
BR1(config-if)# no shutdown
BR1(config-if)# interface g0/0/1
BR1(config-if)# no shutdown
BR2(config)# interface g0/0/0
BR2(config-if)# no shutdown
BR2(config-if)# interface g0/0/1
BR2(config-if)# no shutdown

Step 4: Save the configuration on all gadgets.

BR1# copy running-config startup-config
BR2# copy running-config startup-config

Step 5: Check Connectivity.

a. From BR1, ping BR2’s G0/0/0 interface.

b. From BR2, ping BR1’s G0/0/0 interface.

c. Troubleshoot connectivity points if pings weren’t profitable.

Observe: Pings to the GigabitEthernet LAN interfaces on different routers won’t achieve success. A routing protocol must be in place for different gadgets to pay attention to these subnets. The GigabitEthernet interfaces additionally have to be in an up/up state earlier than a routing protocol can add the subnets to the routing desk. The main focus of this lab is on VLSM and configuring the interfaces.

Reflection Query

Are you able to consider a shortcut for calculating the community addresses of consecutive /30 subnets?

Solutions might range. A /30 community has 4 deal with areas: the community deal with, 2 host addresses, and a broadcast deal with. One other method for acquiring the subsequent /30 community deal with can be to take the community deal with of the earlier /30 community and add 4 to the final octet.

Router Interface Abstract Desk

Observe: To learn how the router is configured, have a look at the interfaces to establish the kind of router and what number of interfaces the router has. There isn’t any strategy to successfully listing all of the combos of configurations for every router class. This desk consists of identifiers for the doable combos of Ethernet and Serial interfaces within the system. The desk doesn’t embody some other kind of interface, regardless that a selected router might include one. An instance of this may be an ISDN BRI interface. The string in parenthesis is the authorized abbreviation that can be utilized in Cisco IOS instructions to characterize the interface.

Machine Configs

Router BR1 (Last Configuration)

BR1# present run
Constructing configuration...


Present configuration : 1558 bytes
!
model 16.9
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
no platform punt-keepalive disable-kernel-core
!
hostname BR1
!
boot-start-marker
boot-end-marker
!
!
vrf definition Mgmt-intf
 !
 address-family ipv4
 exit-address-family
 !
 address-family ipv6
 exit-address-family
!
allow secret 5 $1$ehVu$efQjBqXqcVcSfwLJyhwHT/
!
no aaa new-model
!
no ip area lookup
!
subscriber templating
!
multilink bundle-name authenticated
!
spanning-tree prolong system-id
!
redundancy
 mode none
!
interface GigabitEthernet0/0/0
 description BR1-BR2 Hyperlink
 ip deal with 192.168.33.249 255.255.255.252
 negotiation auto
!
interface GigabitEthernet0/0/1
 description Related to S1
 ip deal with 192.168.33.129 255.255.255.192
 negotiation auto
!
interface Serial0/1/0
!
interface Serial0/1/1
!
interface GigabitEthernet0
 vrf forwarding Mgmt-intf
 no ip deal with
 shutdown
 negotiation auto
!
ip forward-protocol nd
no ip http server
no ip http secure-server
ip tftp source-interface GigabitEthernet0
!
control-plane
!
banner motd ^C Unauthorized Entry is Prohibited ^C
!
line con 0
 password 7 121A0C041104
 login
 stopbits 1
line aux 0
 stopbits 1
line vty 0 4
 password 7 045802150C2E
 login
!
finish

Router BR2 (Last Configuration)

BR2# present run
Constructing configuration...

Present configuration : 1468 bytes
!
model 16.9
service timestamps debug datetime msec
service timestamps log datetime msec
service password-encryption
no platform punt-keepalive disable-kernel-core
!
hostname BR2
!
boot-start-marker
boot-end-marker
!
vrf definition Mgmt-intf
 !
 address-family ipv4
 exit-address-family
 !
 address-family ipv6
 exit-address-family
!
allow secret 5 $1$.s3c$IJxdfZCYkvll8ifXtsW8O/
!
no aaa new-model
!
no ip area lookup
!
subscriber templating
!
multilink bundle-name authenticated
!
spanning-tree prolong system-id
!
redundancy
 mode none
!
interface GigabitEthernet0/0/0
 description BR1-BR2 Hyperlink
 ip deal with 192.168.33.250 255.255.255.252
 negotiation auto
!
interface GigabitEthernet0/0/1
 description Related to S2
 ip deal with 192.168.33.193 255.255.255.224
 negotiation auto
!
interface Serial0/1/0
!
interface Serial0/1/1
!
interface GigabitEthernet0
 vrf forwarding Mgmt-intf
 no ip deal with
 shutdown
 negotiation auto
!
ip forward-protocol nd
no ip http server
no ip http secure-server
ip tftp source-interface GigabitEthernet0
!
control-plane
!
banner motd ^C Unauthorized Entry is Prohibited ^C
!
line con 0
 password 7 0822455D0A16
 login
 stopbits 1
line aux 0
 stopbits 1
line vty 0 4
 password 7 070C285F4D06
 login
!
finish