Today we’ll comment on the two features that work as a complement to the Spanning-Tree. The edged-port command gathers many benefits to the STP, for example, the timeout prevention concerning the DHCP process. As for the bpdu-protection, it prevents loop in the “edged” configured ports within the network via HUBs, “Switches HUB”, etc.
Edged-port
The edged-port feature allows the interface to skip the Listening and Learning states of the Spanning-Tree Protocol, setting the ports into the Forwarding state immediately. The STP’s configuration edged-port enable, forces the interface to ignore the convergence states of the STP, including the notification of topology change messages (TCN messages).
The command must be applied to the access ports connected to servers, workstations, printers, etc.
Configuration
[Switch]interface gigabitethernet 1/0/1 [Switch-GigabitEthernet1/0/1]stp edged-port enable [Switch-GigabitEthernet1/0/1]quit [Switch]interface gigabitethernet 1/0/2 [Switch-GigabitEthernet1/0/2]stp edged-port enable [Switch-GigabitEthernet1/0/2]quit
PS: When a port is configured as a edged-port receives a BPDU, the interface will return to participate on the STP like any other interface.
PS:An Edged-port send BPDUs normally. The edged-port feature is also known as Portfast.
BPDU Protection
The utilization of the edged-port feature is restricted to ports connected to the final equipment such as servers and workstations. When we connect a HUB or Switch to the access ports configured as stp edged-port enable, we take the risk of generating a network loop or thus, affecting the topology stabilization.
The stp bpdu-protection command, protect the ports configured as edged-port from receiving BPDUs. When receiving one, the port will be shutdown.
Configuration
With the example below, we configure the switch as stp bdpu-protection and connect a HUB to the Giga port 1/0/14 configured as stp edged-port enable. We have set a loop in the equipment with a copper cable. The scenario will force the HUB to send back the BPDU messages generated by the Switch in the configured port as edged-port. The bpdu-protection command shall block the connect port to the HUB.
[Switch]stp bpdu-protection [Switch]interface g1/0/14 [Switch-GigabitEthernet1/0/1] stp edged-port enable
After configuration ,the port state will be changed to down.
Display
[Switch]display stp down-port
Down Port Reason
GigabitEthernet1/0/14 BPDU-Protected
Activating the port
In order to set the port again into UP state it is important to remove the HUB’s loop and apply the shutdown command and undo shutdown on the gigabitethernet 1/0/14
[Switch-GigabitEthernet1/0/14]shut [Switch-GigabitEthernet1/0/14]undo shut #Apr 26 12:05:47:785 2000 4800G MSTP/1/IVBPDU:hwPortMstiBpduGuarded: BPDU-Protec tion port 14 received BPDU packet! %Apr 26 12:05:48:364 2000 4800G IFNET/4/LINK UPDOWN: GigabitEthernet1/0/14: link status is DOWN #Apr 26 12:07:43:906 2000 4800G IFNET/4/INTERFACE UPDOWN: Trap 1.3.6.1.6.3.1.1.5.4: Interface 9437197 is Up, ifAdminStatus is 1, ifOperStatus is 1 #Apr 26 12:07:44:108 2000 4800G MSTP/1/PFWD:hwPortMstiStateForwarding: Instance 0's Port 0.9437197 has been set to forwarding state! %Apr 26 12:07:44: 271 2000 4800 G IFNET/4/LINK UPDOWN: GigabitEthernet1/0/14: link status is UP %Apr 26 12:07:44:398 2000 4800G MSTP/2/PFWD:Instance 0's GigabitEthernet1/0/14 h as been set to forwarding state!
PS: For the uplink ports we shall remove the stp edged-port command
[Switch-GigabitEthernet1/0/x]undo stp edge-port
In order to the deactivate the bpdu protection from the Switch, utilize the following command:
[Switch]undo stp bpdu-protection
See you soon!