Notes
Frames
What are frames?
A frame is a digital data transmission unit in computer networking and telecommunication. In packet switched systems, a frame is a simple container for a single network packet. In other telecommunications systems, a frame is a repeating structure supporting time-division multiplexing.
In the OSI_Model of computer networking, a frame is the protocol data unit at the data link layer. Even in TCP_IP .
Why we use frame?
A frame typically includes frame synchronization features consisting of a sequence of bits or symbols that indicate to the receiver the beginning and end of the payload data within the stream of symbols or bits it receives. If a receiver is connected to the system during frame transmission, it ignores the data until it detects a new frame synchronization sequence.
Diagram
Headers change as per frame types. This is ethernet frame headers.
- Preamble , SFD : 7 bytes info that says frame is coming and where frame starts to NIC.
- Destination MAC address : MAC address of receiver(Next node to transfer).
- Source MAX address : MAC address of sender(Changes as per node to node)
- Length : Length of data
- Data : payload or IP packet (Atleast 46 bytes)
- Frame check sequence : Error checking mechanism.