When connecting equipment to a CISCO Switch, the port will flash for 30 seconds in "Orange" before switching to "Green."
The Spanning-tree protocol will check if this connection is not going to create a loop in our network.
Why 30 seconds?
When we plug equipment into a Switch, it will be in two separate states:
If no BDPU frame is received on this port, the switch will put it in the stable state "Forwarding"
We're going to check this out.
I activate the debugging on the spanning tree
Switch debug spanning-tree events Spanning Tree event debugging is on
I plug a customer into the FastEthernet Port 0/1
Switch STP: VLAN0010 Fa0/1 - listening STP: VLAN0010 Fa0/1 - learning STP: VLAN0010 Fa0/1 - forwarding
We can see that our port goes through the Listening /Learning and Forwarding states.
Consequences of his 30 seconds?
These 30 seconds can have serious consequences.
When you log on to a domain, not all GPOs may be executed. If the link is bagote, it will be 30 seconds before the port is in working condition again.
Putting customer access ports directly into the "Forwarding" state with portfast
We have a Switch 24 ports FastEthernet 2 Ports GigaBitEthernet:
FastEthernet ports will serve as our customer access port
GigaBitEthenet ports are going to be our Trunk ports.
We want to activate portfast at all our customer access ports.
To do this, two solutions:
Activate portfast port by port
Switch (config) - range interface Fa 0/1 - 24 Switch (config-if) spanning-tree portfast
Activate Portfast for all Switch ports
Switch (config) spanning-tree portfast default Switch (config) - range interface Gi 1/1 - 2 Switch (config-if) - spanning-tree portfast disable
The spanning-tree portfast default allows the PortFast to be activated on all ports of the switch.
The disable portfast spanning-tree control disables the previously activated PortFast.
As soon as the Portfast is put in place, your equipment will send you a warning message:
%Warning: portfast should only be enabled on ports connected to a single host. Connecting hubs, concentrators, switches, bridges, etc. to this interface when portfast is enabled, can cause temporary bridging loops. Use with CAUTION %Portfast has been configured on FastEthernet0/1 goal will only have effect when the interface is in a non-trunking mode.
% Warning: Portfast should only be activated on ports connected to a single host. Connecting Switches, Hub, Bridges, Concentrators to this interface when the portfast is activated, can cause temporary network loops.
Use with PRECAUTION!
% The Portfast has been configured on FastEthernet0/1 but will only have effect if the interface is in non-trunking mode.
Consequences of Portfast
Our port goes up instantly!!
Now our ports are rising instantly thanks to portfast.
Except that our ports:
– Always consider the BPDU frames received
– Send BPDU frames to these ports.
These ports are considered customer ports! So they don't have to send and receive BPDU frames!
To do this, we will set up:
Hoping this article has been helpful to you! Don't hesitate to let me know!!
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