Ethernet frame size and VLAN tagging are two essential concepts in Ethernet networking. This blog post will explain what they are and why they are important.
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Ethernet Basics
Ethernet is a popular data link layer protocol that is commonly used in local area networks (LANs). It was originally developed by Xerox Corporation in the 1970s. Ethernet uses a Carrier Sense Multiple Access / Collision Detection (CSMA/CD) access method. This means that each node on the network (computer, printer, etc.) listens for traffic before sending any data. If two nodes send data at the same time, a collision occurs and both nodes stop sending data and wait a random amount of time before retrying.
Ethernet Frame Types
Ethernet uses frame types to control how the data is sent and received. There are three different frame types: Unicast, Multicast, and Broadcast.
Unicast frames are sent from one node to another specific node. The destination address in the frame header is the address of the specific node that the data is being sent to.
Multicast frames are sent from one node to a group of nodes. The destination address in the frame header is a special multicast address that identifies the group of nodes that the data is being sent to.
Broadcast frames are sent from one node to all nodes on the Ethernet network. The destination address in the frame header is a special broadcast address that identifies all nodes on the network.
Ethernet also uses two different frame sizes: Standard and Extended.
Standard Ethernet frames can be up to 1518 bytes long, including the preamble and CRC fields. Standard Ethernet frames use 64 byte data fields, which limits the maximum amount of data that can be carried in a single frame.
Extended Ethernet frames can be up to 1522 bytes long, including the preamble and CRC fields. Extended Ethernet frames use 80 byte data fields, which allows for more data to be carried in a single frame. Extended Ethernet frames are sometimes called jumbo frames.
Ethernet Frame Size
Ethernet uses a packet structure called a frame to encapsulate data for transmission. An Ethernet frame can carry a maximum of 1500 bytes of data. If the data to be sent is larger than this, it must be divided into smaller parts, each of which is then sent in a separate frame.
Ethernet also supports a feature called jumbo frames, which allows frames of up to 9000 bytes to be sent. Jumbo frames are primarily used on high-speed local area networks (LANs) where they can improve performance by reducing the overhead associated with sending smaller frames.
##Heading: VLAN Tagging
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In computer networking, a virtual LAN (VLAN) is a logical network that is created on top of a physical network. A VLAN can be used to segment an existing network into separate virtual networks, each of which can have its own security policy and routing rules.
VLANs are often used in large organizations that need to segregate different types of traffic onto separate networks for security or performance reasons. For example, a company might use VLANs to keep sensitive data traffic separate from public internet traffic.
VLANs are also sometimes used to create virtual private networks (VPNs), which allow remote users to securely connect to a private network over the internet.
VLAN Basics
In computer networking, a virtual LAN (VLAN) is a local area network (LAN) that groups together computers in a single broadcast domain. VLANs allow network administrators to segment their networks and reduce broadcast traffic. VLANs are also used to segregate sensitive traffic, such as credit card transactions, from other traffic on the network.
What is a VLAN?
A virtual LAN (VLAN) is a logical group of workstations, servers and networking devices that appear to be on the same LAN despite their geographical distribution. A VLAN has the same attributes as a physical LAN, but it allows for end stations to be grouped together even if they are not on the same network switch.
There are two types of VLANs — static and dynamic. Static VLANs are manually configured by a network administrator and do not change unless the administrator makes changes. Dynamic VLANs use software to automatically assign VLAN membership based on defined criteria such as MAC addresses, port numbers or user login information.
VLANs improve network performance and security by isolating traffic on a single LAN. They also allow for more flexible deployment of end devices since physical location is no longer a factor in determining which devices belong to which LAN.
VLAN Tagging
VLAN tagging is a process of attaching identifying metadata to packets of data to classify them into specific traffic types. This allows network administrators to segregate traffic on their networks and improve security and performance.
There are two types of VLAN tags:
-IEEE 802.1Q: This is the most common type of VLAN tag. It adds a 4-byte header to packets of data, which includes a 2-byte field for identifying the VLAN and a 2-byte field for identifying the priority of the packet.
-ISL (Inter-Switch Link): ISL is a Cisco proprietary protocol that adds a 3-byte header to packets of data. The header includes a 1-byte field for the VLAN ID and a 2-byte field for the CRC (cyclic redundancy check).
VLAN Tagging and Frame Size
When it comes to Ethernet frame size, there are two types of tags: Normal and Extended. VLAN tags are used to identify packets that belong to a specific virtual LAN. Ethernet frames that are untagged are called “native frames.” A VLAN tag is added to an Ethernet frame when the frame is encapsulated with a VLAN header.
VLAN Tagging and Ethernet Frame Size
VLAN tagging is a process that adds a tag, or label, to each Ethernet frame. This tag identifies the VLAN to which the frame belongs. Ethernet frames that are not tagged are automatically placed in the default VLAN, which is usually VLAN 1.
Ethernet frames can be either standard or extended. Standard Ethernet frames have a maximum size of 1518 bytes, while extended Ethernet frames can be up to 1522 bytes in size. Extended Ethernet frames are sometimes used for VLAN tagging, as they allow for a 4-byte tag to be added to the frame.
VLAN tags can be either placed in the header of an Ethernet frame (header-insertion method) or added as an additional field at the end of the frame (trailer method). The header-insertion method is more common, as it is easier to implement and does not require special hardware support.
The addition of a VLAN tag will increase the size of an Ethernet frame by 4 bytes. This means that if you are using extended Ethernet frames for VLAN tagging, the maximum frame size will be 1522 bytes. If you are using standard Ethernet frames, the maximum frame size will be 1518 bytes plus 4 bytes for the tag, for a total of 1522 bytes.
VLAN Tagging and Jumbo Frames
VLAN tags are used to identify traffic on a network. Frames that are untagged are sent to the default VLAN, which is usually the management VLAN. Tagged frames are sent to the VLAN that is specified by the tag.
Jumbo frames are larger than the standard Ethernet frame size of 1500 bytes. They can be up to 9000 bytes in size. Jumbo frames can improve network performance because they can carry more data.
VLAN tags can be used with jumbo frames, but they are not required. If you use VLAN tags, each frame must be tagged with the correct VLAN ID. If you use jumbo frames without VLAN tags, all frames will be sent to the same VLAN.
