User talk:Friday.jimoh1

JIMRealtek Computer Institute
CCNA LAB https://drive.google.com/file/d/1NLMew3ap0xVcMO8GbuQXN44oBbbOotm7/view?usp=sharing

NETWORK LAYER layer 3 of the OSI Model
IP ADDRESSING AND SERVICES A basic and required task for configuring IP is to assign IP addresses to network interfaces. Doing so enables the interface and also allows communication with hosts on those interfaces using IP. Associated with this task are decisions about subnetting and masking the IP addresses.

ASSIGNING IP ADDRESSES TO NETWORK INTERFACE CLASS	ADDRESS OR RANGE	STATUS A	0.0.0.0 1.0.0.0 to 126.0.0.0 127.0.0.0	Reserved Available Reserved B	128.0.0.0 to 191.254.0.0 191.255.0.0	Available Reserved C	192.0.0.0 192.0.1.0 to 223.255.254.0 223.255.255.0	Reserved Available Reserved D	224.0.0.0 to 239.255.255.255	Multicast group address E	240.0.0.0 to 255.255.255.254 255.255.255.255	Reserved Broadcast

An IP address identifies a location to which IP datagrams can be sent. Some IP addresses are reserved for special uses and cannot be used for host, subnets, or network addresses. The official description of IP addresses is found in RFC 1166, internet numbers. An interface can have one primary address. A mask identifies the bits that denote the network number in an IP address. When you use the mask to subnet a network, the mask is then referred to as a subnet mask.

CLASSFUL NETWORK DEFAULT SUBNET MASK IP ADDRESS CLASS	SUBNETMASK	RANGE OF ADDRESS A	255.0.0.0	1.0.0.0 to 126.0.0.0 B	255.255.0.0	128.1.0.0 to 191.254.0.0 C	255.255.255.0	192.0.1.0 to 223.255.254.0

MOST SIGNIFICANT BIT IP ADDRESS CLASS	BIT	RANGE OF ADDRESS A	01	1.0.0.0 to 126.0.0.0 B	10	128.1.0.0 to 191.254.0.0 C	11	192.0.1.0 to 223.255.254.0 D	1110	224.0.0.0 to 239.255.255.255 E	1111	240.0.0.0 to 255.255.255.255

PRIVATE IP ADDRESSES IP ADDRESS CLASS	RANGE OF ADDRESS A	Any addresses that fall within 10.x.x.x B	Any addresses that fall within 172.16.x.x C	Any addresses that fall within 192.168.0.x

UNDERSTANDING SUBNETTING Subnetting allows you to create multiple logical networks that exist within a single Class A, B, or C network. If you do not subnet, you will only be able to use one network from your Class A, B, or C network. Each data link on a network must have a unique network ID, with every node on that link being a member of the same network. If you break a major network (Class A, B, or C) into smaller networks, it allows you to create a network of interconnecting subnetworks. To subnet a network, extend the natural mask using some of the bits from the host ID portion of the address to create a subnetwork ID. Every Class of IP address has a default subnet. Subnet mask is an IP address that logically separate the network ID of the address from the Host ID address.

CLASSLESS INTER-DOMAIN ROUTING (CIDR) Classless Inter-Domain Routing (CIDR) is the method that Internet Service Provider (ISP) used to allocate IP addresses in block sizes. When you receive a blocks of IP addresses from an ISP, what you get will look something like 192.168.1.0/28, this is saying something about what the subnetmask of the IP address is. The slash(/) notation is also called the prefix notation and its telling us how many bits are turn ON in mask.

BORROWED BIT	BINARY VALUE	DECIMAL VALUE 1	10000000	128 2	11000000	192 3	11100000	224 4	11110000	240 5	11111000	248 6	11111100	252 7	11111110	254 8	11111111	255

S/N	SUBNETMASK	CIDR VALUE CLASS A	1. 255.0.0.0	/8	2.		255.128.0.0	/9	3.		255.192.0.0	/10	4.		255.224.0.0	/11	5.		255.240.0.0	/12	6.		255.248.0.0	/13	7.		255.252.0.0	/14	8.		255.254.0.0	/15 CLASS B	9. 255.255.0.0	/16	10.		255.255.128.0	/17	11.		255.255.192.0	/18	12.		255.255.224.0	/19	13.		255.255.240.0	/20	14.		255.255.248.0	/21	15.		255.255.252.0	/22	16.		255.255.254.0	/23 CLASS C	17. 255.255.255.0	/24	18.		255.255.255.128	/25	19.		255.255.255.192	/26	20.		255.255.255.224	/27	21.		255.255.255.240	/28	22.		255.255.255.248	/29	23.		255.255.255.252	/30	24.		255.255.255.254	/31 Broadcast 	25. 255.255.255.255	/32 Identifying the Network and Broadcast Addresses of a Subnet Work 1.	CIDR- Classless Inter-Domain Routing It represent the number of bit that are turn ON in 32bit address going from left to right e.g. CIDR value of /24 means 24bits are turn ON and that is the default subnetmask of Class C IP addresses.

2.	Network Address or Network ID This is the address that identifies the subnet of a Host e.g. 192.168.1.0/24

3.	Host Address This is the unicast addresses assigned to the end device network e.g. 192.168.1.1/24, 192.168.1.2/24, 192.168.1.3/24, etc

4.	Broadcast Address This is an IP address that allows information to be sent to all hosts in a given subnet.

5.	Binary This is a Base2 number system

6.	Binary Inversion This is the inversion of 1’s to 0’s. Binary Number	Binary Inversion 1	0 1	0 1	0 0	1 0	1 1	0 0	1 1	0

7.	Bitwise AND Operation This is represented by A&B symbol and this symbol returns in 1’s if both corresponding bit are one.

A (input)	B(Input)	Z(Output) 1	0	0 0	0	0 1	0	0 1	1	1 0	1	0 1	1	1 0	1	0 1	0	0

8.	Bitwise OR Operation This is represented by A/B symbol and it returns in 1’s if any of both of the corresponding bit are one

A (input)	B(Input)	Z(Output) 1	0	1 0	0	0 1	0	1 1	1	1 0	1	1 1	1	1 0	1	1 1	0	1

STEPS TO IDENTIFYING THE NETWORK AND BROADCAST ID

A.	GETTING NETWORK ID 1.	Convert the IP address and CIDR to binary. 2.	Use Bitwise AND Operation on the IP address and CIDR to return corresponding values of the IP and CIDR address, this will give us network ID.

Example

IP Address: 	192.168.1.15 CIDR:		255.255.255.0 (/24)

IP ADDRESS/CIDR CONVERSION IN BINARY AND USING BITWISE AND OPERATION

IP Address in Binary:   11000000  10101000  00000001  00001111 CIDR in Binary:              11111111  11111111  11111111  00000000 Network ID in Binary: 11000000  10101000 00000001 00000000 192	     168	           1                0

Therefore, the network ID is 192.168.1.0/24

This means that 192.168.1.15/24 belongs to the network of 192.168.1.0/24.

B.	GETTING THE BROADCAST ADDRESS 1.	To get the broadcast address, first of all carryout the Binary Inversion of the CIDR. 2.	Then, carryout a Bitwise OR Operation on the Binary Network and the Inverted CIDR address to get out Broadcast address.

Example BINARY INVERSION ON CIDR

CIDR in Binary:  	11111111  11111111  11111111  00000000 Inverted CIDR:		00000000 00000000  00000000  11111111

USING THE BITWISE OR OPERATION

Network ID: 		11000000  10101000  00000001  00000000 Inverted CIDR:		00000000 00000000  00000000  11111111 Broadcast ID:		11000000 10101000 00000001 11111111 NETWORK ADDRESS 		= 	192.168.1.0/24 HOST ADDRESS		=	192.168.1.15/24 BROADCAST ADDRESS	=	192.168.1.255/24

VARIABLE LENGTH SUBNET MASK (VLSM) It is a technique that allows network administrators to divide an IP address into subnets of different sizes. It could be referred to as a way of subnetting a subnet.

Example Assuming we have received a block of IP addresses from an ISP in the form of 192.168.1.0/24. This is clearly a Class C addresses and we want to setup networks with this block of IP addresses with three different locations (A, B, and C).

LOCATION A 	=	50 hosts LOCATION B	= 	30 hosts LOCATION C	=	10 hosts

CHEAT TABLE Bit Value	128	64	32	16	8	4	2	1 Borrowed Bit	1	2	3	4	5	6	7	8 Subnetmasks	128	192	224	240	248	252	254	255 Prefix/CIDR	/25	/26	/27	/28	/29	/30	/31	/32 Source: CLASS C Cheat Table

SOLUTIONS

LOCATION A	 = 	50 Hosts •	The Bit value 64 is closer to 50 in the cheat table. •	We are borrowing 2bits which is under 64. •	Prefix/CIDR is /26 in our cheat table. •	Only one network is available from ISP which is 192.168.1.0/24

ISP Network address in Binary: 11000000  10101000  00000001  00000000 ISP CIDR in Binary: 	           	    11111111   11111111  11111111  00000000

BINARY INVERSION CIDR/PREFIX OF /26 in our cheat table is 255.255.255.192

CIDR in Binary: 11111111   11111111  11111111  11000000 Inverted CIDR:  00000000   00000000   00000000  00111111

USING BITWISE OR OPERATION ISP Network address: 192.168.1.0

ISP Network address in Binary: 11000000  10101000  00000001  00000000 Inverted CIDR:  			    00000000  00000000  00000000  00111111 First Usable Host Address:	   11000000 10101000 00000001 00111111

Location A First Usable Host IP Address in Decimal: 192.168.1.63/26

LOCATION B	 = 	30 Hosts •	The Bit value 32 is closer to 30 in the cheat table. •	We are borrowing 3bits which is under 32. •	Prefix/CIDR is /27 in our cheat table. •	Only one network is available from ISP which is 192.168.1.0/24

ISP Network address in Binary: 11000000  10101000  00000001  00000000 ISP CIDR in Binary: 	           	    11111111   11111111  11111111  00000000

BINARY INVERSION CIDR/PREFIX OF /26 in our cheat table is 255.255.255.224

CIDR in Binary: 11111111   11111111  11111111  11100000 Inverted CIDR:  00000000   00000000   00000000  00011111

USING BITWISE OR OPERATION ISP Network address: 192.168.1.0

ISP Network address in Binary: 11000000  10101000  00000001  00000000 Inverted CIDR:  			    00000000  00000000  00000000  00011111 First Usable Host Address:	   11000000 10101000 00000001 00011111

Location B First Usable Host IP Address in Decimal: 192.168.1.31/27

LOCATION C	 = 	10 Hosts •	The Bit value 16 is closer to 10 in the cheat table. •	We are borrowing 4bits which is under 16. •	Prefix/CIDR is /28 in our cheat table. •	Only one network is available from ISP which is 192.168.1.0/24

ISP Network address in Binary: 11000000  10101000  00000001  00000000 ISP CIDR in Binary: 	           	    11111111   11111111  11111111  00000000

BINARY INVERSION CIDR/PREFIX OF /26 in our cheat table is 255.255.255.224

CIDR in Binary: 11111111   11111111  11111111  11110000 Inverted CIDR:  00000000   00000000   00000000  00001111

USING BITWISE OR OPERATION ISP Network address: 192.168.1.0

ISP Network address in Binary: 11000000  10101000  00000001  00000000 Inverted CIDR:  			    00000000  00000000  00000000  00001111 First Usable Host Address:	   11000000 10101000 00000001 00001111

Location B First Usable Host IP Address in Decimal: 192.168.1.15/27

Therefore: LOCATION A FIRST USABLE HOST IP ADDRESS IS 192.168.1.63/26 LOCATION B FIRST USABLE HOST IP ADDRESS IS 192.168.1.31/27 LOCATION C FIRST USABLE HOST IP ADDRESS IS 192.168.1.15/28

Assignment

Given network of 204.15.5.0/24, develop a subnetting scheme using VLSM

Net A	=		62 Hosts Net B	=		126 Hosts Net C	=		2 Hosts Net D	=		14 Hosts Net E	=		6 Hosts

Determine what mask allows the required number of hosts using the Cheat Table.

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