11-26-2021 03:09 AM
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
11-26-2021 04:04 AM
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.
11-26-2021 05:59 AM
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.
11-27-2021 08:40 AM
Admin disabled - shutdown command. In RSTP, the port state is "discarding" even if you admin disable it.
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