Extracted from course materials.
"VIDs are associated with only those frames that traverse a trunk link. When a frame enters or exits the switch on an access link, no VID is present. The ASIC on the switch port assigns the VID to a frame as it is placed on a trunk link and also strips off the VID if the frame exits an access switch port."
1) "When a frame enters or exits the switch on an access link, no VID is present." If there is no VID on a frame when it enters an access port, why was it even mentioned that there is no VID when the frame exits the access port? OR does it mean that a frame is tagged with a Vlan ID whenever it enters an access port but the Vlan ID is removed when the frame exits an access port?
2) "The ASIC on the switch port assigns the VID to a frame as it is placed on a trunk link and also strips off the VID if the frame exits an access switch port." Isn't the VID removed as soon as the frame reaches the receiving end of the trunk link? The sentence seems to imply that the VID is not removed at the end of the trunk link, and is only removed when the frame exits an access port.
Any effort to clarify the confusion would be deeply appreciated!
1) Frame entering an access port is NOT tagged with any Vlan ID. That in turn implies that any frame exiting access ports do not have any Vlan ID.
2) Frame entering a trunk link will be tagged with the Vlan ID that is based on the access port that the frame enters. ie. If the frame enters an access port configured for Vlan 10, then the frame will be tagged with a Vlan 10 tag before entering a trunk link.
3) When a tagged frame reaches the end of the trunk link on the receiving switch, the frame will be stripped of its Vlan ID tag. Based on the Vlan ID that the frame had just before it exits the trunk link, the untagged frame is then flooded out on all access ports that are configured with the same Vlan ID.
Yes, IF the destination MAC address does not exist in the switch's MAC address table. If it does, it will forward the packet out the corresponding port.
4) However, if the trunk is encapsulated with dot1q, the frame will not be tagged if the frame had entered an access port that is configured with a vlan that is part of the dot1q trunk's native vlan. At the receiving end of the dot1q trunk, the untagged frame will be then be flooded out on all access ports that are configured with vlan that is the same as the dot1q trunk's native vlan.
Yes, but be aware that a lot of native vlan traffic is generated by the switch itself, like CDP packets and STP BPDUs.
As for the flow you have given: Remeber that flooding only occurs if the destination MAC address is not in the MAC address table.
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