uplinkfast and backbonefast

[jonk34567]

uplinkfast and backbone fast  can be used only in stp

portfast can be used on both stp and Rstp 

Are those statements are correct  ? 

[Julio E. Moisa · Accepted solution]

Hi

Uplink Fast : This is to enable the blocked port when the root port link is failed.

For example, you can enable uplinkfast on C when the normal link betwen B and A goes down, or on B when the normal link goes down between C and A. So you will be saved in such kind of situations.

Backbone. Fast:- This can be enabled when the switch doesn't have blocked port and root port receives inferior BPDU.

If the inferior BPDU arrives on the root port and there are no blocked ports, the switch assumes that it has lost connectivity to the root bridge, causes the maximum aging time on the root to expire, and the switch then becomes the root switch according to normal spanning-tree rules.

Reference: https://supportforums.cisco.com/discussion/9133731/backbone-fast-vs-uplink-fast.

About the portfast, this feature is used in Spanning tree to connect the hosts immediately instead to be waiting for listening and learning states, so it will be moved to forward states. Normal STP has 5 port states but when you are enabling Rapid STP, it optimize the states to use 3 instead 5.

Please dont forget to rate the comment if it is useful.

:-)

[Joseph W. Doherty]

Are those statements are correct  ? 

Believe so.

Understand uplinkfast and backbone fast are proprietary features available in some/most versions of Cisco's STP.

As standard rapid-STP includes similar features, they are not needed with Cisco's rapid-STP either.

Portfast was also a proprietary feature within Cisco's STP.  Standard rapid-STP, I believe, has a similar feature that Cisco chose to enable still using the Portfast command.  (Also understand, many of standard rapid-STP features "borrowed" from Cisco's proprietary STP enhancements.)