Contents
What are duplicate packets?
Duplicate packets are packets that are captured twice or multiple times by Observer. Typically, duplicates are a result of how data is sent to Observer . For a switch, the use of a SPAN/mirror port and/or trunk is required to capture data.
How is data transported at the data link layer?
Data-link layer takes packets from Network Layer and encapsulates them into Frames. Then, it sends each frame bit-by-bit on the hardware. At receiver’ end, data link layer picks up signals from hardware and assembles them into frames. Data-link layer provides layer-2 hardware addressing mechanism.
How are IP packets transmitted through the data link layer?
When the packet arrives on the receiving host, the packet travels through the TCP/IP protocol stack in the reverse order from which it was sent. The physical network layer receives the packet in its frame form. The physical network layer computes the CRC of the packet, then sends the frame to the data link layer.
Where does the data link layer take packets?
network layer
The data link layer takes the packet from the network layer and breaks it into frames. The header in this layer provides the source and destination MAC addresses.
What happens at the data link layer?
The data link layer takes the data bits and “frames,” and creates packets of the data to guarantee reliable transmission. This layer adds source and destination addresses to the data stream as well as information to detect and control transmission errors.
What are the duties of data link layer?
The duties of data link layer include packetizing, adderssing, error control, flow control, medium access control. Answer: The data link layer is responsible for logical link control, media access control, hardware addressing, error detection and handlingand defining physical layer standards.
What is the purpose of the data link layer?
What is the data link layer responsible for?
The data link layer is responsible for multiplexing data streams, data frame detection, medium access, and error control. It ensures reliable point-to-point and point-to-multipoint connections in a communication network.
What does the data link layer do?
Layer 2 of The OSI Model: Data Link Layer provides the functional and procedural means to transfer data between network entities and to detect and possibly correct errors that may occur in the physical layer.
What happens when a duplicate ACK is sent in TCP?
After seeing duplicate ACK, the sender knows that 3 is lost and sends packet 3 again immediately. The receiver receives ACK with sequence number 7. SACK is an option in TCP, which enables the receiver to send an acknowledgment packet with the range (block) of sequence numbers over a connection.
When to send duplicate ACK to the receiver?
When the receiver receives packet 6. it sends ACK with sequence number 3 (Expecting next packet). After seeing duplicate ACK, the sender knows that 3 is lost and sends packet 3 again immediately. The receiver receives ACK with sequence number 7.
What is the header in the data link layer?
The header in this layer provides the source and destination MAC addresses. It is the data link layer that will convert the data into binary digits such as 1 and 0 and then prepare them for the physical layer. This layer has to be aware of what type of network interface card (NIC) is being used in order to prepare the packet in a certain way.
What kind of devices are at the data link layer?
The data link layer combines data bits into entities called frames. Network topologies like Ethernet exist at the data link layer. Network switches are the most common network devices that exist at the data link layer. View chapter Purchase book