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1 Rookie

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32 Posts

5248

April 8th, 2021 01:00

Configure tagged native vlan and untagged on S4048-ON

Hello,

I am trying to achieve a particular thing:

 

Every untagged packet should be tagged as VLAN 100

Every tagged packet of VLAN 101 should pass by.

 

I have tried the following configuration:

 

interface port-channel123
  no shutdown
  switchport mode trunk
  switchport access vlan 100
  switchport trunk allowed vlan 101
!
interface ethernet 1/1/1
  no shutdown
  channel-group 123
  no switchport
!

 


In this case the tagged 101 vlan works well. But the untagged traffic does not get tagged as 100.

Any suggestions what am I missing?

3 Apprentice

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73 Posts

April 9th, 2021 08:00

Hi nikog,

the configuration on your Dell switch is correct and matches the Cisco setting.

You may confirm this by checking MAC addresses learned on port-channel 23:

show mac address-table interface port-channel 23

 

This command should display MAC addresses in both VLANs.

I think the problem is the egress (outgoing) port then as VLAN 100 traffic will get tagged internally in the switch

but needs a destination port with "switchport trunk allowed vlan 100" to get these frames out tagged with VLAN 100.

Tim

Moderator

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3.8K Posts

April 8th, 2021 09:00

Hello,

what OS version are you using?

Thanks

Marco

1 Rookie

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32 Posts

April 8th, 2021 10:00

Hi, when I run `show running-configuration` it says: 

Version 10.5.2.0P1

Moderator

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9.2K Posts

April 8th, 2021 11:00

Is the traffic staying untagged on VLAN 100? The switchport access vlan 100 should mean the untagged traffic uses VLAN 100, but it doesn’t tag the traffic it just passes it as untagged.

 

1 Rookie

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32 Posts

April 8th, 2021 13:00

The traffic which is tagged with VLAN 101 goes through as expected.

Untagged traffic does not seem to do it.
What I would like to achieve is that the untagged traffic (without VLAN) is tagged as VLAN 100.

I come from Cisco background and this is how I do it on a Cisco switch

 

 

interface Ethernet1/2
  switchport
  switchport mode trunk
  switchport trunk native vlan 100
  switchport trunk allowed vlan 100-101
  no shutdown

 

 


That way the traffic without VLAN is passed as VLAN 100.
 
I am trying to do the same with my Dell switch

Moderator

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9.2K Posts

April 8th, 2021 13:00

What is the output of show vlan?

1 Rookie

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32 Posts

April 18th, 2021 05:00

Hi,


Tim, your suggestion was correct - mostly.


The issue I faced was because I had a cisco <-> dell switch trunk port connection, but I had configured the dell wrongfully. 

However, it really helped me to hear that I was on the right path and the configuration I have put is the correct. I was reading the docs but I was not completely sure about that.

1 Rookie

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17 Posts

January 18th, 2023 08:00

Hi

I have related issue and this is between DELL S4148T--Arista 7050 uplink. I have DELL as Top of the Rack with vlan 10 untagged on all the port-channel. This is the config for the uplink port channel to the Arista leaf switch:

DELL SWITCH 

interface port-channel20
no shutdown
switchport mode trunk

switchport access vlan 10 (untagged)

switchport trunk allowed vlan 20,30(tagged)
vlt-port-channel 20

 

ARISTA SWITCH

interface Port-Channel14
switchport mode trunk
switchport trunk allowed vlan 10,20,30
mlag 14

Does vlan 10 need to be configure as untagged on the uplink? or it need to be configure as tagged?

1 Rookie

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17 Posts

January 18th, 2023 09:00

Thanks for the response. It is still about to go into testing environment but as it stands, I have all the vlan tagged on the uplink. Like you suggested if it does not work I will untagged only vlan 10 on the uplink. 

Moderator

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9.4K Posts

January 18th, 2023 09:00

Haryortheyji,

 

It really depends on your environment, usually uplink ports have everything tagged, but if for some reason you have untagged traffic passing through the uplink on vlan 10 you can set it to untagged.

Now in my opinion if it is working you shouldn't change it, if it isn't working then you should try it as untagged. 

 

Let me know if this helps.

 

 

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