Layer 3,4 and 7
Layer 3
Switches are on the second layer of the OSI model (Data Link); they do filtering based on host MAC addresses. You may also see a third layer switch; they not only provide all switching capabilities but some layer three routing capabilities too.
Data link layer
Protocol layers may be defined in such a way that the communications within a layer is independent of the operation of the layer being being used. This is known as "peer-to-peer" communication and is an important goal of the OSI Reference Model. Each layer provides a protocol to communicate with its peer. When a packet is transmitted by a layer, a header consisting of Protocol Control Information (PCI) is added to the data to be sent. In OSI terminology, the packet data (also known as the Payload) is called a Protocol Data Unit (PDU). The packet so-formed, called a Service Data Unit (SDU) is passed via a service access point to the layer below. This is sent using the service of the next lower protocol layer.
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.
Every layer add its relevant data, (required for various typical operations such as identify packet location, sender/ receiver addresses, App. ports, etc) along with actual data to transmit. Where as, every activities related to Packet is typically being performed in Network Layer/ IP layer.
Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.Packet switching is considered part of layer 3 of the OSI model.
The Network Layer
Different textbooks may give you different answers to this question. In several I've seen, the "packet" is complete in the data link layer (layer 2) and is known as a 'frame' in the physical layer (layer 1). Others may indicate a packet is the result of the physical layer (layer 1). In other descriptions the terms packet and frame are interchanged in the layer 1 and 2 of the OSI model.
Layer 4 (Transport) is responsible for correction.
Layer 3 of the OSI model. An ICMP header follows the IP header of the IP packet.
Decapsulation
Network - Always identifies the final destination of a packet
TheHub work on layer 1 i.e. Physical layer of OSI Model
LAPD
It depends on which textbook you are reading; some textbooks state that the frame is constructed in the data link layer (layer 2) and transmitted out the physical layer as a packet. Some other textbooks will say that the packet is created in layer 2 and transmitted out the physical layer as a frame.
Packet switching breaks the original data into smaller segments per packet before transmission. This is done in the layer 4 transport layer of the OSI model.
is responsible for packet forwading include routing through intermediate device