Place the steps of IEEE 802.1Q frame processing in sequential order, starting from when a host sends traffic on VLAN 20 until it is delivered to a host on another switch across an 802.1Q trunk link.
- 1The ingress switch receives an untagged Ethernet frame from the source host on an access port configured for VLAN 20.
- 2The ingress switch inserts a 4-byte 802.1Q tag header containing the VLAN 20 identifier into the frame.
- 3The ingress switch transmits the tagged Ethernet frame across the 802.1Q trunk link.
- 4The egress switch receives the tagged frame and inspects the 802.1Q header to identify the target VLAN.
- 5The egress switch strips the 4-byte 802.1Q tag from the Ethernet frame header.
- 6The egress switch forwards the original untagged Ethernet frame out the VLAN 20 access port to the destination host.
Answer
The sequence starts when the ingress switch receives an untagged frame from a host on a VLAN 20 access port, inserts a 4-byte 802.1Q tag into the frame header, transmits the tagged frame over the trunk link, the egress switch reads the VLAN ID from the tag, removes the 802.1Q header, and delivers the untagged frame out the access port to the destination host.
When a frame traverses an IEEE 802.1Q trunk link, the ingress switch inserts a 4-byte tag into the frame header to identify the originating VLAN (unless it is the native VLAN). The frame travels across the physical trunk link carrying this tag. Upon reaching the remote switch, the egress switch inspects the tag to determine the VLAN association, strips the 4-byte tag header, and delivers the original untagged Ethernet frame to the destination device connected to an access port in that VLAN.
Step-by-Step Solution
Key Concept
IEEE 802.1Q Frame Encapsulation, Tagging, and Decapsulation Mechanics