Confusion around RSTP 802.1w disabled role

[daan-ce]

Hi

Studying for the CCNA, I'm a bit confused about the definition of the RSTP disabled role

I find multiple sources stating that "disabled" means that the port is administratively disabled.

However, in the official course guide a few paragraphs later it is explained that if a root port has failed, it will become a disabled port although not administratively disabled.

So should the definition of "disabled port" be "any port in the RSTP topology that is not root, alternate or designated port, possibly because it's admin disabled"?

Thanks

[ashok_boin]

Hi,

You are right. The port gets admin disabled but the port state is still "Discarding" state in 802.1w than calling it as "disabled" state. When you enabled the port, then the port may move from discarding to listening, learning and forwarding states.

STP (802.1D) Port State RSTP (802.1w) Port State Is Port Included in Active Topology? Is Port Learning MAC Addresses?

Disabled	Discarding	No	No
Blocking	Discarding	No	No
Listening	Discarding	Yes	No
Learning	Learning	Yes	Yes
Forwarding	Forwarding	Yes	Yes

Please find the following link for detailed study on this.

Understanding Rapid Spanning Tree Protocol (802.1w) - Cisco

Regards..

Ashok.

[daan-ce]

By admin disabled, you mean the shutdown command under interface configuration mode? Or is RSTP able to put ports in an admin disabled state that is different from admin disable using the shutdown command?

Because this is where it gets confusing to me.

[ashok_boin]

Admin disabled - shutdown command. In RSTP, the port state is "discarding" even if you admin disable it.