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Community Member

Access Port Vlan ID

Hi,

Why is the vlan ID for the access ports connecting 2 switches do no need to be the same, yet traffic still flow through?

I understand if they are trunk ports, the vlan id have to be matched.

Cheers,

Pei

2 ACCEPTED SOLUTIONS

Accepted Solutions
Bronze

Access Port Vlan ID

Hi Pei,

If switches are connected together using access ports, then VLAN IDs don't have any effect.

An access port sends all traffic out UNTAGGED, so to a connected device, there is no knowledge of VLANs.

So  Switch1 G1/0/1 Access Port VLAN100  <-> Switch2 G1/0/1 Access Port VLAN200  will work absolutely fine...  infact what you are actually doing is BRIDGING VLAN100 on one switch to VLAN200 on the other switch.

You should be careful doing this in a live environment though as you may not want this bridging to occur for security reasons.

Hope That Helps!

Nick

Purple

Access Port Vlan ID

Hi,

for trunks the native vlan must be the same on both ends and CDP will let you know if you misconfigured but for access ports as there are no tags you can put them into 2 different vlans but it is considered bad practice.But communication will only work in certain cases.

Regards.

Alain

Don't forget to rate helpful posts.
2 REPLIES
Bronze

Access Port Vlan ID

Hi Pei,

If switches are connected together using access ports, then VLAN IDs don't have any effect.

An access port sends all traffic out UNTAGGED, so to a connected device, there is no knowledge of VLANs.

So  Switch1 G1/0/1 Access Port VLAN100  <-> Switch2 G1/0/1 Access Port VLAN200  will work absolutely fine...  infact what you are actually doing is BRIDGING VLAN100 on one switch to VLAN200 on the other switch.

You should be careful doing this in a live environment though as you may not want this bridging to occur for security reasons.

Hope That Helps!

Nick

Purple

Access Port Vlan ID

Hi,

for trunks the native vlan must be the same on both ends and CDP will let you know if you misconfigured but for access ports as there are no tags you can put them into 2 different vlans but it is considered bad practice.But communication will only work in certain cases.

Regards.

Alain

Don't forget to rate helpful posts.
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