9

VLAN

The type of screen you see here depends on the VLAN Type you selected in the Switch Setup screen. This chapter shows you how to configure 802.1Q tagged and port-based VLANs.

9.1 Introduction to IEEE 802.1Q Tagged VLANs

A tagged VLAN uses an explicit tag (VLAN ID) in the MAC header to identify the VLAN membership of a frame across bridges - they are not confined to the switch on which they were created. The VLANs can be created statically by hand or dynamically through GVRP. The VLAN ID associates a frame with a specific VLAN and provides the information that switches need to process the frame across the network. A tagged frame is four bytes longer than an untagged frame and contains two bytes of TPID (Tag Protocol Identifier, residing within the type/length field of the Ethernet frame) and two bytes of TCI (Tag Control Information, starts after the source address field of the Ethernet frame).

The CFI (Canonical Format Indicator) is a single-bit flag, always set to zero for Ethernet switches. If a frame received at an Ethernet port has a CFI set to 1, then that frame should not be forwarded as it is to an untagged port. The remaining twelve bits define the VLAN ID, giving a possible maximum number of 4,096 VLANs. Note that user priority and VLAN ID are independent of each other. A frame with VID (VLAN Identifier) of null (0) is called a priority frame, meaning that only the priority level is significant and the default VID of the ingress port is given as the VID of the frame. Of the 4096 possible VIDs, a VID of 0 is used to identify priority frames and value 4095 (FFF) is reserved, so the maximum possible VLAN configurations are 4,094.

TPID

User Priority

CFI

VLAN ID

2 Bytes

3 Bits

1 Bit

12 bits

 

 

 

 

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ZyXEL Communications metrogigabit switch manual Introduction to Ieee 802.1Q Tagged VLANs, 117, Tpid, CFI Vlan ID
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metrogigabit switch specifications

ZyXEL Communications has long been a prominent player in the networking hardware industry, providing innovative solutions that cater to both business and consumer markets. Among their notable offerings is the Metrogigabit switch, a device designed to meet the high demands of modern networks.

The ZyXEL Metrogigabit switch is primarily aimed at service providers and large enterprises, recognizing the need for seamless connectivity in an increasingly digital world. This switch is engineered for scalability, enabling users to effortlessly expand their network as their operational needs grow. With support for high bandwidth, it is particularly suited for environments requiring extensive data traffic management, such as data centers and campus networks.

One of the standout features of the Metrogigabit switch is its high-density gigabit Ethernet ports, which provide a backbone for reliable data transmission. The switch typically supports multiple 10G SFP+ uplinks, ensuring fast and efficient connections to upstream devices. This capability allows users to configure their networks to handle large volumes of data quickly and without interruption.

In terms of technology, the Metrogigabit switch leverages advanced Layer 2 and Layer 3 functionalities. This includes features such as VLAN support for traffic segmentation, Quality of Service (QoS) for prioritizing mission-critical applications, and robust multicast management. These capabilities contribute to enhanced network efficiency and performance.

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In summary, the ZyXEL Metrogigabit switch is an essential tool for organizations seeking robust performance, reliability, and security in their networking infrastructure. With its high-density ports, flexible configuration options, and comprehensive management features, it provides a strong foundation for building efficient and scalable networks. Whether for service providers or enterprises, this switch stands out as a reliable choice in the fast-evolving technological landscape.
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