Labs

Lab13/Lab 13 Subnetting Worksheet(3).docx

Liberty University

CSIS 331

Lab 13 Subnetting Worksheet

Topology

Requirements

IPv4 Addressing

· Create subnets that meet the host requirements using 192.168.100.0/24.

NOTE: You may use the table on the last page as a reference to assist you.

Step 1: Subnet the 192.168.100.0/24 network into the appropriate number of subnets.

a. Based on the topology and host requirements, how many subnets are needed? _____

NOTE: Donʻt forget the routers need one subnet to talk to each other. So far your Subnet Bitmap looks like this: nnnnnnnn.nnnnnnnn.nnnnnnnn.hhhhhhhh (n=network bits covered by subnets mask h = host bits)

b. How many bits, if any, must be borrowed to support the number of subnets needed in the topology table?

n =____ (Formula is 2n = subnets). n being the number of subnet bits.

NOTE: Remember you have a 24 bit subnet mask (Class C). The binary form looks like this 11111111.11111111.11111111.00000000. How many bits do you need get the amount of subnets you need?Try to use the formula 2n to calculate close to what you need. For example you donʻt need 62 subnets.

c. How many subnets does this create? ____ = 2 n

d. How many usable hosts does this create per subnet? _____

NOTE: Always subtract 2 host IPʻs for Network and Broadcast IP addresses. You already have 2 8 - 2 = 254 hosts before subnetting but you do not need that many hosts per subnet. (n=network/mask bits covered by subnets mask, s=subnet bits h = host bits) Your binary bitmap should now look something like this. nnnnnnnn.nnnnnnnn.nnnnnnnn.sssshhhh (n=network/mask bits covered by subnets mask, s=subnet bits h = host bits). However many bits you borrowed you add to the CIDR of /24. For example if you borrowed 4 extra bits then your CIDR would be /28.

e. Calculate the binary value for the first five subnets.. The first subnet is already shown. List them in the table below.

Remember these binary values: 128 64 32 16 8 4 2 1. Subtract from left to right to get your binary answer. If there is a remainder that matches closely to binary column enough to subtract mark a 1 in that column otherwise mark a 0. You should have eight 0 and 1s

1st Octet:

Can you subtract 128 from 192? Yes. Place a 1 in the 1st binary column. Remainder is 64.

Can you subtract 64 from 64? Yes. Place a 1 in the 2nd binary column. Remainder is 0.

Mark six zeroes for the rest of the binary columns as you cannot subtract further.

2nd Octet:

Can you subtract 128 from 168? Yes. Place a 1 in the 1st binary column. Remainder is 40.

Can you subtract 64 from 40? No.Place a 0 in the 2nd binary column.

Can you subtract 32 from 40? Yes. Place a 1 in the 3nd binary column. Remainder is 8.

Can you subtract 16 from 8? No. Place a 0 in the 4th binary column.

Can you subtract 8 from 8? Yes. Place a 1 in the 5th binary column. Remainder is 0 .

Mark three zeroes for the rest of the binary columns as you cannot subtract further.

3rdOctet:

Can you subtract 128 from 100? No. Place a 0 in 1st binary column.

Can you subtract 64 from 100? Yes.Place a 1 in the 2nd binary column. Remainder is 36.

Can you subtract 32 from 36? Yes. Place a 1 in the 3nd binary column. Remainder is 4.

Can you subtract 16 from 4? No. Place a 0 in the 4th binary column.

Can you subtract 8 from 4? No. Place a 0 in the 5th binary column.

Can you subtract 4 from 4? Yes. Place a 1 in the 6th binary column. Remainder is 0 .

Mark two zeroes for the rest of the binary columns as you cannot subtract further.

f. Calculate the binary and decimal values of the new subnet mask. Mark them in the Mask 4th octet columns in the table below. Begin with Network 0. Note: You may not need to use all rows.

	IP	Mask
	1st Octet	2nd Octet	3rd Octet	4th Octet	1st Octet	2nd Octet	3rd Octet	4th Octet
Network 0 “Zero Subnet”	192 11000000	168 10101000	100 01100100	0 00000000	255 11111111	255 11111111	255 11111111
Network 1	192 11000000	168 10101000			255 11111111	255 11111111	255 11111111
Network 2	192 11000000	168 10101000			255 11111111	255 11111111	255 11111111
Network 3	192 11000000	168 10101000			255 11111111	255 11111111	255 11111111
Network 4
Network 5
Network 6
Network 7
Network 8
Network 9
Network 10

g. Fill in the Subnet Table, listing the decimal value of all available subnets, the first and last usable host address, and the broadcast address. Repeat until all addresses are listed.

Note: You may not need to use all rows.

Subnet Table

Example shows 192.168.1.0/27 subnet mask (blocks of 32).

Subnet Number	Subnet Address	First Usable Host Address	Last Usable Host Address	Broadcast Address
Example	ex. 192.168.1.0	ex.192.168.1.1	ex. 192.168.1.30	ex. 192.168.1.31
	ex. 192.168.1.32	ex.192.168.1.33	ex. 192.168.1.62	ex. 192.168.2.63
0
1
2
3
4
5
6
7
8
9
10

Step 2:Assign the subnets to the network shown in the topology.

a. Assign Subnet 0 to the LAN connected to the GigabitEthernet 0/0 interface of R1. Mark here the subnet range:

b. Assign Subnet 1 to the LAN connected to the GigabitEthernet 0/1 interface of R1. Mark here the subnet range:

c. Assign Subnet 2 to the LAN connected to the GigabitEthernet 0/0 interface of R2. Mark here the subnet range:

d. Assign Subnet 3 to the LAN connected to the GigabitEthernet 0/1 interface of R2. Mark here the subnet range: :

e. Assign Subnet 4 to the WAN link between R1 to R2. Mark here the subnet range:

Step 3: Addressing Table

a. Assign the first usable IP addresses to R1 for the two LAN links and the WAN link.

b. Assign the first usable IP addresses to R2 for the LANs links. Assign the last usable IP address for the WAN link.

c. Assign the second usable IP addresses to the switches.

d. Assign the last usable IP addresses to the hosts.

NOTE: Do not use the Subnet address or Broadcast address of each subnet as they are not usable addresses to assign to a host.

Addressing Table

Device	Interface	IP Address	Subnet Mask	Default Gateway
R1	G0/0
	G0/1
	S0/0/0
R2	G0/0
	G0/1
	S0/0/0
S1	VLAN 1
S2	VLAN 1
S3	VLAN 1
S4	VLAN 1
PC1	NIC
PC2	NIC
PC3	NIC
PC4	NIC

Ping Table:

Ping From Device	Ping to Device IP	Possible Y/N	If no, Why Not? What did you do to resolve?
R1	S3
R1	PC4
S3	PC4

R1 Show Run Output

S3 Show Run Output

CIDRs for mask 0.0.0.0	/1	/2	/3	/4	/5	/6	/7	/8
CIDRs for mask 255.0.0.0	/9	/10	/11	/12	/13	/14	/15	/16
CIDRs for mask 255.255.0.0	/17	/18	/19	/20	/21	/22	/23	/24
CIDRs for 255.255.255.0	/25	/26	/27	/28	/29	/30	/31	/31
Subnet Mask	128	192	224	240	248	252	254	255
Magic Number	128	64	32	16	8	4	2	1
# of Subnets or Hosts Needed	255	127	63	31	15	7	3	1
Bits Borrowed	1	2	3	4	5	6	7	8

Source: https://www.interfacett.com/blogs/subnetting-tcpip-network-using-magic-box-method/