Portfast: With conventional STP operation a laptop computer after booting have to wait at least 30 secs ( fifteen listening ,fifteen learning ) for transmit and or receive data . Portfast facilitate the laptop computer to be online going past the listening & learning state of switch port .
To configure the PortFast in Switch use the below command:
Switch(config-if)# spanning-tree portfast.
Alternate command with same result-
Switch(config-if)# switchport host.
An access-layer switch which has redundant uplink connections to 2 distribution-layer switches . Usually , one uplink could be in the Forwarding state so the other could be in the Blocking state . In the event that the primary uplink went down , about 50 secs could elapse before the redundant uplink could be used . The UplinkFast feature on Cisco switches helps in leaf-node switches and or switches at the ends of the spanning-tree branches to possess a functioning root port whilst maintaining more than one of the redundant or potential root ports in Blocking mode . Any time the primary root port uplink fails , another one blocked uplink instantly can be brought up for use .
To configure Uplinkfast in Switches use the below command:
Switch(config)# spanning-tree uplinkfast [max-update-rate pkts-per-second]
In the network backbone , or even core layer , a totally different method would be used to shorten STP convergence . BackboneFast operates by having a switch actively determine whether or not alternative paths are available to the root bridge , in the event the switch detects an indirect link failure . Indirect link failures happen when a link which is not directly connected to a switch fails . A switch detects an indirect link failure any time it receives inferior BPDUs from its designated bridge on both its very own root port or a blocked port .(Inferior BPDUs are sent from a designated bridge that has lost its connection to the root bridge , which makes it declare itself as the new root)
To configure the BackboneFast in Switch use the below command:
Switch(config)# spanning-tree backbonefast.
When ever used , BackboneFast has to be enabled on all switches in the network as
BackboneFast require the use of the RLQ Request and Reply mechanism to tell switches of Root Path stability . The RLQ protocol is active only if BackboneFast is enabled on a switch . By default , BackboneFast is disabled .