# Rapid Spanning-Tree Configuration

**URL:** https://forum.networklessons.com/t/rapid-spanning-tree-configuration/1139
**Category:** Lessons Discussion
**Created:** [December 27, 2016, 4:29pm UTC](https://forum.networklessons.com/t/rapid-spanning-tree-configuration/1139 "2016-12-27T16:29:05Z")
**Posts on this page:** 1
**Showing post:** 14

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### Author: ![lagapidis](https://cdn-forum.networklessons.com/user_avatar/forum.networklessons.com/lagapidis/32/4949_2.png) [@lagapidis](https://forum.networklessons.com/u/lagapidis)
#### Post date: [August 25, 2020, 8:42am UTC](https://forum.networklessons.com/t/rapid-spanning-tree-configuration/1139/14 "2020-08-25T08:42:36Z")

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Hello Abdul

> [@Moeedeng](#):
>
> Whats P2p in type ?

Take a look at this post:

> [@Rapid Spanning-Tree (RSTP)](https://forum.networklessons.com/t/rapid-spanning-tree-rstp/1138/90):
>
> Hello Abdul Yes, this is an important clarification that you are asking for. Regardless of RSTP, in general terms, a point to point interface is one that uses a point to point technology, such as a serial interface. On such an interface, only one single device can be connected on the other end of the circuit. Conversely, Ethernet is not considered a point to point technology, but a broadcast technology, because you can have multiple devices on a single network segment. Looking at these ter…

> [@Moeedeng](#):
>
> now sw2 is he root bridge not SW1 ?

Based on the debug output you have displayed here, it looks like on SW3, Fa0/14 was originally the root port of the switch, but it is “going down”. Therefore, a new root port had to be designated, and it looks like the switch chose Fa0/16 for the new root port.

On SW2, it looks like Fa0/14 went down on this switch as well. The initial result was that SW2 made itself the root bridge. But in the meantime, it received a superior BPDU on Fa0/16, which informed SW2 that another switch will become the root. Therefore, SW2 changes its own role (it is no longer the root bridge), and thus it must choose a root port, choosing Fa0/16 for this role.

So to answer your question, no SW2 is not the root bridge. It temporarily became the root bridge until it received a superior BPDU. Remember that these events take place quite quickly and can occur in a different order each time. SW3 didn’t get a chance to become root bridge, but immediately received the appropriate BPDU on Fa0/16 to make that root port. While SW2 decided to become the root bridge until a superior BPDU is received, which it was. But these things happen so quickly that the order doesn’t really matter. For users, the quickness of reconvergence is still quite fast.

> [@Moeedeng](#):
>
> how fa0/2 is designated in fa0/2 ?

Fa0/2 is a new port that just came up. It becomes designated immediately simply because it didn’t receive a superior BPDU on that port.

I hope this has been helpful!

Laz

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