ICND2: Portfast, BPDU Guard and Etherchannel

Portfast:  Configured at Access layer – ports which end hosts use.

BPDU Guard: puts port in error if another switch with STP connected

Configure Portfast and BPDU Guard on Switch 2, int fa0/2

Switch#conf t

Enter configuration commands, one per line. End with CNTL/Z.

Switch(config)#int fa0/2

Switch(config-if)#spanning-tree portfast

%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 FastEthernet0/2 but will only

have effect when the interface is in a non-trunking mode.

Switch(config-if)#switchport mode access

Switch(config-if)#switchport access vlan 1

Switch(config-if)#exit

Switch(config)#int fa0/2

Switch(config-if)#spanning-tree bpduguard enable

Switch(config-if)#exit

——————————————————

Etherchannel

The commands to configure an etherchannel:

int range fa0 – 3
switchport mode trunk
channel-group 1 mode active

The choices of etherchannel type:

–active Enable LACP unconditionally

–auto Enable PAgP only if a PAgP device is detected

–desirable Enable PAgP unconditionally

–on Enable Etherchannel only

–passive Enable LACP only if a LACP device is detected

Switch 0 running config:

interface FastEthernet0/1

channel-group 1 mode active

switchport mode trunk

!

interface FastEthernet0/2

channel-group 1 mode active

switchport mode trunk

!

interface FastEthernet0/3

channel-group 1 mode active

switchport mode trunk