How many bytes is an 802.1Q tag in length?

How many bytes is an 802.1Q tag in length?

• A. 2 bytes
• B. 4 bytes
• C. 6 bytes
• D. 8 bytes

Answer: (B)

An 802.1Q tag is precisely 4 bytes in length. This tagging is crucial in Ethernet networking as it allows for virtual LAN (VLAN) identification and helps in the management of traffic over a network. The tag consists of several fields: a 2-byte Tag Protocol Identifier (TPID) that identifies the tag as an 802.1Q tag, and a 2-byte Tag Control Information (TCI) field containing information about the VLAN ID and priority. The combination of these fields adds up to the total of 4 bytes, enabling switches and routers to recognize and correctly handle frames associated with different VLANs. Understanding this structure is essential for configuring and troubleshooting VLANs in a network environment.

An 802.1Q tag is precisely 4 bytes in length. This tagging is crucial in Ethernet networking as it allows for virtual LAN (VLAN) identification and helps in the management of traffic over a network.

The tag consists of several fields: a 2-byte Tag Protocol Identifier (TPID) that identifies the tag as an 802.1Q tag, and a 2-byte Tag Control Information (TCI) field containing information about the VLAN ID and priority. The combination of these fields adds up to the total of 4 bytes, enabling switches and routers to recognize and correctly handle frames associated with different VLANs. Understanding this structure is essential for configuring and troubleshooting VLANs in a network environment.