Networking Concept

Mac address

• Media control access
• It is physical address to identify the devices
• it identify the NIC of each divices (NIC–> Network identification card)
• ex:- ether 00:0c:49:0a:43:03
• Mac work in the second and third layer of the OSI model
• Specially it is related to the switches

TCP –VS– UDP

TCP

• Transmission COntrol Protocol
• Connection oriented protocol
• used in HTTPS/SSH/TelNet/SMTP/FTP
• provide the more security and relailablity
• it form one-to-one connection and it gurantee the complete delivery of data
• Three way hand shake
• SYN -> SYN-ACK -> ACK
• it is slow due to three-way-handshake, it take time to complete and establis the connection
• Use port to establish the connection
• During hand-shake it acknowldge your machine to the requested server
• contains the 20Byte packet

UDP

• User Datagram Protocol
• Connection less Protocol
• it provide the fast transmission
• Broadcast or multicast the message and the complete delivery of data is note guarnted
• Streamming on voice-over-io(VOIP), DHCP,DNS
• Used for streaming the data like procast, video
• contains the 8Byte packet

Comman Ports and Protocol

TCP

  PROTOCOL/SERVICE                            PORT'S
    FTP                                        21
    SSH                                        22                                     
    TelNet                                     23
    SMTP                                       25
    DNS                                        53
    HTTP/HTTPS                                 80/443   
    POP3                                       110
    SMB                                        139+445
    IMAP                                       143

UDP

  PROTOCOL/SERVICE                            PORT'S
    DNS                                        53  
    DHCP                                       67.68
    TFTP                                       69
    SNMP                                       161

The OSI Model

• Open Systems Interconnection(OSI)

• Learn this mnemonic to to know the seven layer sequence

• Please Do Not Throw Sausage Pizza Away

• OSI seven layers are

    1. Physical                               (P)Please
    2. Data link                              (D)Do
    3. Network                                (N)Not
    4. Transport                              (T)Throw
    5. Session                                (S)Sausage
    6. Presentation                           (P)Pizza
    7. Application                            (A)Away
  

• OSI Model Explain REF

  Layers                                        For
  1. Physical --                               Provide the connection between computer and network, it includes physical datacable,server
  2. Data Link --                              Make sure the data-transfer is error-free between different node, when data packet arrive at network layer then data link layer(DLL) deliver that packet to the requested host using MAC address.
  3. Network --                                Transmitt the data from one host to other, in different netwroks.It also place the reciver/sender ip address in header of packet.
  4. Transport --                              Data packet referred as Segment, it is responsible for the end-to-end delivery of complete message without any error/packet loss.
  5. Session --                                Responsible for the establishing the session,maintaining and also ensure the security
  6. Presentation ---                          Data from application layer(layer 7) is extracted here and manipulate as per the required to transmit over network.
  7. Application ---                           Used by the end user software such as web browser and email clients.

While Receiving the data from network model work from layer 1 –> layer 7

While sending the data from machine model work from layer 7 –> layer 1

Networks

• IP address are work with the third layer of the OSI Model

• There are two types of ip address

  • IPv4 : 192.168.34.123
  • IPv6 : 23:s3:3w:34:dw:23:2d

• In IPv4 each section after delimeter(.) is contain the 8 bits each (0 & 1)

• The total of complete ip address is 32 byte.

• the total in terms of the bits is 256 that is from 0 to 255.

• There are many network around you and your system and all are having the very specific identity number that is known as IP address.

• Types of ip address in a network

  Class	Start ip	End ip	Subnet Mask	Netwroks(max)	Hosts(max)
  A	0	127	255.0.0.0	126	16,646,144
  B	127	191	255.255.0.0	16,383	15,024
  C	192	223	255.225.255.0	2097,151	254

• IP address in the binary format

  • 11111111.11111111.11111111.0 == 255.255.255.0
  • == 192.168.15.

• Some Standard Slash Network

  • /24 Network

    128	64	32	16	8	4	2	1
    1	0	0	0	0	0	0	0

  • /25 Network

    128	64	32	16	8	4	2	1
    1	1	0	0	0	0	0	0

Links

It is getting hard for me to write and draw the ahed so i am adding some link of my document go through them, Some link to internet resources

1. 7_second_subnating
2. subnet_execl_sheet
3. my_hand_written_notes