TRANSPORT LAYER
The transport layer ensures that messages are delivered error-free, in sequence, and with no losses or duplications. It relieves the higher layer protocols from any concern with the transfer of data between them and their peers.
The size and complexity of a transport protocol depends on the type of service it can get from the network layer. For a reliable network layer with virtual circuit capability, a minimal transport layer is required. If the network layer is unreliable and/or only supports datagrams, the transport protocol should include extensive error detection and recovery.
The transport layer provides:
Typically, the transport layer can accept relatively large messages, but there are strict message size limits imposed by the network (or lower) layer. Consequently, the transport layer must break up the messages into smaller units, or frames, prepending a header to each frame.
The transport layer header information must then include control information, such as message start and message end flags, to enable the transport layer on the other end to recognize message boundaries. In addition, if the lower layers do not maintain sequence, the transport header must contain sequence information to enable the transport layer on the receiving end to get the pieces back together in the right order before handing the received message up to the layer above.
Network Layer
network layer
Data Link Layer
It encapsulates with a header and a trailer to create a frame.
Session Layer traced lost Packets.
tunneling
Layer 2 or the 'Data' layer of the OSI model encapsulates either 'bits' from the physical layer (1)- moving up the TCP stack or 'Packets' from the Network layer (3)- going down the the stack. 7 - Application Layer DATA 6 - Presentation Layer DATA 5 - Session Layer DATA 4 - Transport Layer SEGMENT 3 - Network Layer PACKET 2 - Data Layer (Incorporating LLC and MAC) FRAME 1 - Physical Layer BIT A good nmemonic for remembering the data encapsulation in the OSI model is 'Don't Some Peolple Fry Bacon' - Data, Segments, Packets, Bits.
At which layer lost packets are traced?
Telegrams are sent in data packets. Bits packet frame segment data mean data packet and they belongs to Data link layer. Bye.
The Network layer (Layer 3, typically IP) will receive a segment from the Transport layer (Layer 4, typically TCP or UDP), and will add its own header to it to create a packet. The size of the packet will thus always be the size of the segment plus the Network layer header, the same as when the next layer down (the Data Link layer, layer 2, typically Ethernet) encapsulates the packet into a frame for transmission.
the network layer --> check your question. ^^^^^^^^^^^^^^^^^^^^^^^^^^^ That is totally not the right answer, how about you actually read the book for the course. It is the data link layer that does encapsulation. I agree - its the Data Link Layer which encapsulates the Network layer...NOT the Network Layer.
voip
Network Layer ( 3 )