Example 3, 1D Trunk Connection to 802.1Q VLAN Network

3.When Switch 2 receives the tagged frame on its Port 2, it checks the frame’s VLAN Tag Header and determines that the frame is classified as belonging to the Red VLAN, and that the frame is a broadcast frame. Switch 2 forwards the frame to all ports in the Red VLAN Forwarding List excluding Port 2, which received the frame. In this example, the only eligible port is Port 3, which connects to Bridge 4. Switch 2 checks its Forwarding List, which specifies that the VLAN frame type for that port is untagged. Switch 2 then updates its Source Address Table in FID 3 for MAC address “Y” if necessary. The untagged frame is then transmitted out Port 3 to Bridge 4. Bridge 4 forwards the frame out all its ports because it is a broadcast frame, and the server receives it as shown in Figure 4-6.

Figure 4-6 Transmitting to Bridge 4

Floor 3

Blue Industries

 

Redco

 

 

 

2

File Server

Bridge 3

2

Bridge 4

3

 

1

 

Blue VLAN

 

Red VLAN

 

Floor 2

 

 

 

 

 

 

2263_16

4.The File Server responds with a unicast frame to User A. All switches between the File Server and User A have an entry in their respective Source Address Tables identifying which port to use for forwarding the frame to User A, MAC address “Y” in FID 3. All switches update their Source Address Tables for the File Server’s MAC address “Z” as the frame is forwarded through the switch fabric to User A. The 802.1D switches update their Source Address Tables based on the source MAC address and receive port and the 802.1Q switches update their databases based on the source MAC address, VLAN, and receive port.

5.The frame from the File Server is received on Switch 2, and forwarded to Switch 1 as a tagged frame classified as belonging to the Red VLAN. Switch 1 removes the tag and forwards the frame to Bridge 1, which in turn forwards the frame out of the port attached to User A. All subsequent frames between User A and the File Server are forwarded through the switch fabric in the same manner.

4.3EXAMPLE 3, 1D TRUNK CONNECTION TO 802.1Q VLAN NETWORK

This example illustrates the use of a 1D Trunk to connect a device to a network of 802.1Q VLAN switches.

4-8Examples

Page 68
Image 68
Enterasys Networks manual Example 3, 1D Trunk Connection to 802.1Q Vlan Network, Transmitting to Bridge

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.