MikroTik​​​​​ ISO Model

OSI MODEL

            Open Systems Interconnection was developed by ISO in 1977.

-Why a layered Network Model?

            -Reduces complexity

            -Standardizes interfaces

            -Facilitates modular engineering

            -Ensures interoperable technology

            -Accelerates evolution

            -Simplifies teaching and learning

 LAYER 2-MAC ADDRESS

-Media Access Control Address is a 48-bit length address in Data Link Layer (Layer 2)
 of the OSIModel.

-MAC Address in physical address, typically burned-in to hardware at the factory and should be Unique.

-In a computer, MAC address is usually address of Network Interface Card (NIC) or wireless adaptor.

-Expressed as 6 groups of 2 hexadecimal digits, separated by hyphens (-) or colons (:)

            - The first 6 digits are Organizationally Unique Identifier (OUI), represent the vendor.

            - The rest of the digits are vendor-assigned end-station address for identifying the     
               thernet Hardware.

 -     For example: 02-00-4D-4F-00-50

LAYER 3- IP ADDRESS

-IP (Internet Protocol) address is address in Network Layer (Layer 3) of the OSI model.

-Different from MAC address, IP address is logical and flexible, mean that we can change and adjustIt.

-There are 2 kind of IP Address

            - IPv4

                        - 32 bits length.

                        - Totally 2 ^{^} 32 = 4,294,967,296 (4.2 billion) address.

            -IPv6

                        -128 bits length.

                        -Totally 2 ^{^} 128 = 340,282,366,920,938,463,374,607,431,768,211,456 (340  
                          decllion)  Addresses.

IPv4 ADDRESSING

-IPv4 has 32-bit of address length.

-Expressed in dotted decimal notation, divided into 4 pieces of 8-bit (octet):

            - For example:                       192.168.1.1

            - Binary:                                 11000000 10101000 00000001 00000001

            - Each octet’s value:            00000000~11111111 (0~255)

            - IPv4 range:                         0.0.0.0~255.255.255.255

IPv4 SUBNETTING

-Subnetting is a way to separate and distribute IP addresses into multiple blocks (subnets):

            - Smaller networks are easier to manage.

            -Overall traffic is reduced.

            - You can more easily apply network security policies.

-Hosts that located in the same subnet can communicate with each other directly without involvement Of the router.

IPv4 SUBNETTING (Cont.)

-Subnet Mask is used to determine the size and IP range of the subnet:

            - Network ID or Network IP is the first IP address of a subnet, used for identifying a network.

            - Broadcast IP is the last IP address of a subnet, use for sending broadcast traffic to all hosts

            In the subnet.

            -Host IPs are IP addresses that we can actually assign on end hosts, it is between Network ID

            And Broadcast IP.

-Subnet Mask uses the same notation as IPv4 address:

            -For example:            255.255.255.0

            -Binary:                      111111111111111111111111 00000000

            -This subnet mask is 24 bits.

CALCULATE AN IP RANGE

-Let’s try this example:

            -IP Address:              192.168.1.1

            -Subnet Mask:          255.255.255.0

-Calculation steps:

            1. Convert IP Address and Subnet Mask to Binary.

            2. Count how many “1” in Subnet Mask bits, remain particular number of bits in IP Address

            Unchanged and use them as IP Prefix.

            3. Replace the rest bits in IP Address to 0 to find Network ID.

            4. Replace the rest bits in IP Address to 1 to find Broadcast IP.

            5. Convert Network ID and Broadcast IP back to Decimal.

            6. Host IPs are between Network ID and Broadcast IP.

DECIMAL TO BINARY CONVERSION

192.168.1.1

128     64        32        16        8          4          2          1

1          1          0          0          0          0          0          0

1          0          1          0          1          0          0          0

0          0          0          0          0          0          0          1

0          0          0          0          0          0          0          1

Result: 11000000 10101000 00000001 00000001

BINARY TO DECIMAL CONVERSION

            
 11000000 10101000 00000001 00000001

            128     64        32        16        8          4          2          1

            1      1      0      0      0      0      0      0

        128 + 64 = 192

            1      0      1      0      1      0      0      0

        128 + 32 + 8 = 168

            0      0      0      0      0      0      0      1
         
         0      0      0      0      0      0      0      1

Result: 192.168.1.1

CALCULATE AN IP RANGE (CONT.)

-Convert to Binary

            -IP Address:                 11000000 10101000 00000001 00000001

            -Subnet Mask:             11111111 11111111 11111111 00000000

-Subnet Mask has 24 “1”, so IP Prefix is 24-bit length:

            -IP Prefix:                    11000000 10101000 00000001

            -Network ID:                11000000 10101000 00000001 00000000

            -Broadcast IP:              11000000 10101000 00000001 11111111

-Convert back to Decimal:

            -Network ID:                192.168.1.0

            -Broadcast IP:              192.168.1.255

            -Host IPs:                     192.168.1.1 ~ 192.168.1.255

            -Total Addresses:        256

            -Usable Addresses:      256 – 2 = 254

IP CALCULATION TOOLS

-Calculator in Windows

            -Use Programmer Mode

-Online IP / Subnet Calculators:

            - http://www.subnet-calculator.com

- http://www.subnet-calculator.org

- http://www.subnetmask.info