Ethernet PDU
1. Introduction
1.1 Ethernet Protocol
1.2 What is PDU?
2. Ethernet PDU Structure
2.1 Ethernet Header
2.1.1 Preamble
2.1.2 Destination MAC Address
2.1.3 Source MAC Address
2.1.4 EtherType/Length
2.2 PDU Payload
2.2.1 Data Frame
2.2.2 Control Frames
3. Ethernet PDU Example
3.1 Basic Ethernet PDU
3.2 VLAN Ethernet PDU
4. Conclusion
1. Introduction
1.1 Ethernet Protocol
Ethernet is a widely used networking technology for transmitting data over a network. It follows a set of rules and standards known as the Ethernet protocol, which defines how data is transmitted and received.
1.2 What is PDU?
PDU stands for Protocol Data Unit. In the context of Ethernet, a PDU refers to the unit of data that is transmitted over the Ethernet network. It contains both the header and payload of the Ethernet frame.
2. Ethernet PDU Structure
2.1 Ethernet Header
The Ethernet PDU starts with a header, which includes essential information about the frame.
2.1.1 Preamble
The preamble is a sequence of alternating 1s and 0s that helps the receiving device synchronize with the incoming data. It consists of 7 bytes of data followed by a delimiter.
2.1.2 Destination MAC Address
The destination MAC address is the unique hardware address of the device intended to receive the frame. It is 6 bytes long and is used to identify the recipient.
2.1.3 Source MAC Address
The source MAC address is the unique hardware address of the device that generated the frame. It is also 6 bytes long and is used to identify the sender.
2.1.4 EtherType/Length
The EtherType/Length field specifies the type of the payload or the length of the payload in the frame. It helps the receiving device identify the protocol used in the payload.
2.2 PDU Payload
The payload is the actual data being transmitted in the Ethernet frame.
2.2.1 Data Frame
A data frame contains the payload data, which can be any type of data such as an email, file, or video. It is encapsulated within the Ethernet frame and is transmitted to the destination device.
2.2.2 Control Frames
Control frames are special types of frames that are used for network management and control purposes. They contain control information and are not associated with any payload data.
3. Ethernet PDU Example
3.1 Basic Ethernet PDU
An example of a basic Ethernet PDU would be a data frame containing a file being transmitted from one device to another. The header would include the MAC addresses of the sending and receiving devices, along with the EtherType/Length field. The payload would consist of the file data.
3.2 VLAN Ethernet PDU
In a VLAN (Virtual Local Area Network) Ethernet PDU, an additional tag is added to the Ethernet header. This tag identifies the VLAN to which the frame belongs and helps in segregating traffic within a network.
4. Conclusion
The Ethernet PDU is the unit of data transmitted over an Ethernet network. It consists of a header that includes the preamble, MAC addresses, and EtherType/Length field, along with the payload, which can be data or control frames. Understanding the structure of the Ethernet PDU is essential for network administrators and engineers working with Ethernet networks.
