VLAN Terms

1.4VLAN TERMS

To fully understand the operation and configuration of port based VLANs, it is essential to understand the definitions of several key terms.

VLAN ID

A unique number (between 1 and 4094) that identifies a particular VLAN.

VLAN Name

A 32-character alphanumeric name associated with a VLAN ID. The VLAN Name is intended to make user-defined VLANs easier to identify and remember.

Filtering Database Identifier (FID)

Addressing information that the device learns about a VLAN is stored in the filtering database assigned to that VLAN. Several VLANs can be assigned to the same FID to allow those VLANs to share addressing information. This enables the devices in the different VLANs to communicate with each other when the individual ports have been configured to allow communication to occur.

The configuration is accomplished using the Local Management VLAN Forwarding Configuration screen. By default a VLAN is assigned to the FID that matches its VLAN ID.

Tag Header (VLAN Tag)

Four bytes of data inserted in a frame that identifies the VLAN/frame classification. The Tag Header is inserted into the frame directly after the Source MAC address field. Twelve bits of the Tag Header represent the VLAN ID. The remaining bits are other control information.

Tagged Frame

A data frame that contains a Tag Header. A VLAN aware device can add the Tag Header to any frame it transmits.

Untagged Frame

A data frame that does not have a Tag Header.

Default VLAN

The VLAN to which all ports are assigned upon initialization. The Default VLAN has a VLAN ID of 1 and cannot be deleted or renamed.

Forwarding List

A list of the ports on a particular device that are eligible to transmit frames for a selected VLAN.

1-4Virtual Local Area Networks

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Enterasys Networks 802.1Q manual Vlan Terms, Vlan ID

802.1Q specifications

Enterasys Networks, a subsidiary of the Siemens Group, is widely recognized for its comprehensive networking solutions, with a strong emphasis on security, reliability, and performance. One of the key technologies offered by Enterasys is 802.1Q, a critical component of Ethernet networking that establishes standards for VLAN (Virtual Local Area Network) tagging. This technology is essential for enhancing network performance and managing traffic efficiently.

The primary feature of 802.1Q is its ability to create VLANs, which segment a physical network into multiple logical networks. This segmentation improves network security by isolating sensitive data and restricting access to specific users or devices. With VLANs, organizations can reduce broadcast traffic, thereby enhancing overall network efficiency. Different departments within an organization can operate on their own VLAN, ensuring that their traffic is kept separate from others.

One significant technological aspect of 802.1Q is its tagging method. When a frame passes through a switch port configured for IEEE 802.1Q, the switch appends a VLAN tag to the frame. This tag contains important information, such as the VLAN ID, enabling switches and devices throughout the network to identify which VLAN the frame belongs to. This tagging is especially critical in environments where multiple VLANs share the same physical infrastructure.

Another characteristic of Enterasys Networks' implementation of 802.1Q is interoperability with existing network standards and protocols. This means that organizations can implement VLAN tagging without requiring major upgrades or replacements of their switch hardware. Enterasys ensures that its switches are compliant with various industry standards, making it easier for enterprises to integrate these solutions into their existing network settings.

Security is another vital feature of Enterasys Networks’ 802.1Q offering. By leveraging VLANs, organizations can enforce stricter access controls and policies, reducing the risk of unauthorized access to sensitive network segments. This is particularly beneficial for industries with stringent compliance requirements, such as finance and healthcare.

In summary, Enterasys Networks' 802.1Q technology plays a pivotal role in modern networking by facilitating VLAN creation, enabling efficient traffic management, ensuring interoperability, and bolstering network security. As organizations increasingly rely on connected devices and data-driven processes, technologies like 802.1Q are essential for building robust, scalable, and secure networking environments.