DataLink Layer

 DataLink Layer by GateSmasher:

• The datalink layer is used for hop to hop delivery i.e from one node to another node.
• In the below pic if a packet has to be sent from a host(Eg:A3) in network A to anothet node (Eg:B4) in network B,Its responsibilty of network layer to send data across network.
• Datalink reposibiliy is to send data from A2 to Router 1 and Router 1 to Router 2 and Router 2 to B4.
  
  
  
  

• Other Main Functions DataLink layer

1. Flow Control 

• Stop and wait
• Goback N
• Selective Repeat

     2. Error Control

• Parity
• CRC(Cyclic Redundancy Check)
• Checksum

     Note:Above 3 are used for deteching error,we use Hamming Code for error correction

  3. Access Control:   

• Aloha(Pure Aloha and Slotted Aloha)
• CSMA/CD(Carrier Sense Multiple Access/Collision Detection ) and CSMA/CA(Carrier Sense Multiple Access/Collision Avoidance)
• Token Ring etc