Adding an existing untagged member port of vlan Default as tagged can cause STP configuration loss.


Userlevel 1
New to Extreme switches, and using EXOS version 22. Why do I see this message when adding the same port tag and untagged. Adding an existing untagged member port of vlan Default as tagged can cause STP configuration loss.

8 replies

Userlevel 2
I believe MSTP is enabled on 22.x by default. By default, the Default untagged VLAN is used as the Carrier VLAN for the s0 STP domain. However, once ports are removed from the Default VLAN or the VLAN is disabled, a tagged Carrier VLAN must be defined if STP will be enabled in the network. I think this is the reason you get the warning message.
Userlevel 7
Sushruth Sathyamurthy wrote:

I believe MSTP is enabled on 22.x by default. By default, the Default untagged VLAN is used as the Carrier VLAN for the s0 STP domain. However, once ports are removed from the Default VLAN or the VLAN is disabled, a tagged Carrier VLAN must be defined if STP will be enabled in the network. I think this is the reason you get the warning message.

that has been introduced with 22.2. You need to start with a default factory config from that version (or above) to see it by default.
Userlevel 2
You can refer to this article. Hope it helps - https://gtacknowledge.extremenetworks.com/articles/Q_A/What-is-a-STP-Carrier-vlan
Userlevel 1
What is the impact of the statement? Also, how can I avoid this from happening again.
Userlevel 2
nola saint wrote:

What is the impact of the statement? Also, how can I avoid this from happening again.

I do not believe this statement has an impact. It is merely a warning message as per your carrier VLAN configuration. The Default untagged VLAN is the carrier VLAN for the s0 STP domain. If you change that, this warning message will appear as carrier VLAN must be present for all STP protected ports.
Userlevel 1
Thanks, it helps a little. Do you have any real-world examples of why, when, where and how to implement this?
Userlevel 2
nola saint wrote:

Thanks, it helps a little. Do you have any real-world examples of why, when, where and how to implement this?

I'm not sure I understand your question. Are you needing configuration example in a switch? https://gtacknowledge.extremenetworks.com/articles/How_To/How-to-configure-RSTP-in-EXOS
Userlevel 1
After configuring other switches I read again one of your post and I think I understand that its just a warning.

[img]https://www.gravatar.com/avatar/2352c1b2b41515286ae626b77fd1b477?d=identicon&s=100&r=PG[/img]

Sushruth Sathyamurthy, Employee

  • 784 Points [img]https://d2r1vs3d9006ap.cloudfront.net/badges/4/500_badge_2x_thumb.png[/img]

I do not believe this statement has an impact. It is merely a warning message as per your carrier VLAN configuration. The Default untagged VLAN is the carrier VLAN for the s0 STP domain. If you change that, this warning message will appear as carrier VLAN must be present for all STP protected ports.
  • Like

Reply