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VLAN tagging on Access Port

HuyDC
Level 1
Level 1

Dear you all,

First of all, I would like to say thank you all in community, your posts are really helpful

I am wondering about VLAN tagging on Access port

In my opinion :

Ex: Client A- Fa0/1(Switch1)Fa0/2 - Access -Fa0/1(Switch2)Fa0/2- Client B

Fa0/1 & Fa0/2 are Access Port access VLAN 10

1. Client send the frame with no VLAN information

2. When switch received frame on Fa0/1, it will tagged VLAN ID 10 to this frame, look at Mac address tablet  to find out which port the frame need to forward to. It's Fa0/2

3. When Fa0/2 received frame, it check the VLAN ID, if it match with access VLAN on Fa0/2 port so it remove VLAN ID tag and sent out. So on the access link, frame has no VLAN tag

https://networkdirection.net/articles/network-theory/taggeduntaggedandnativevlans/#Untagged_VLANs 

But some discussion tell me that frame has not been tagged when it receive on Fa0/1 port & internally switch the frame are not tagged.

https://community.cisco.com/t5/switching/native-vlan-vs-trunk-vs-default-vlan-understanding/m-p/2673259/highlight/true#M321782 

So could you help me to define that which one is right. Does the frame has been tagged from fa0/1 until fa0/2 on Switch 1.

Thanks you all for your help.

15 Replies 15

Cisco switches support per-vlan mac-address tables.

Ports not assigned to any vlan will always exist in default vlan 1. vlan 1 cannot be deleted.

So .. if a port is assigned to a vlan, a switch can lookup the mac-address-table for MAC-Port-Vlan entry to forward the frames.

If the port is not assigned to a vlan it will have entry for MAC-Port-Vlan for vlan 1.

 

what's switchport access vlan 10 meaning on port.

As I understood now, after enter this command and plug the client in, switch will insert "MAC Port VLAN" into MAC address table. 

Thats right, to be 100% clear, the entry is added when the client generates some traffic.