10-13-2009 09:54 PM - edited 03-06-2019 08:06 AM
Hi,
In practical Scenario when to use MSTP and PVST.
What is difference between bpdugard and Bpdufilter.
10-13-2009 11:33 PM
Bpdufilter is typically used in conjunction with portfast. When bpdufilter is enabled you do not send any bpdus out the interface. If you hear a bpdu you take the port out of portfast state.
With bpduguard if you hear a bpdu you put the interface in err-disabled state.
The bpdufilter feature is available so you can say spanning-tree portfast default to make every port a portfast port. Ports that receive bpdus will be non-portfast.
Bpduguard should be used on ports that you know should never be connected to devices running spanning-tree on the other end of the link.
The difference between the two is the action. Bpdufilter is to revert to non-portfast state, while bpduguard is to revert to err-disabled state.
10-13-2009 11:34 PM
Hello Nasr,
MST 802.1s provides:
higher scalability: it can handle better hundreds to thousands of vlans
multi-vendor support: being a standard can be the best solution in multivendor contexts when all devices support it.
drawbacks:
configuration has to be replicated manually everywhere and requires careful planning.
because you can associate non-existing vlans to instances it is recommended to do so: divide the 4094 possible vlans in 64 subsets and freeze MST config.
When a new Vlan is needed depending on desired topology pick up one in the subset associated to a specific MST instance.
PVST+ or Rapid PVST:
cisco proprietary
less scalable
more user friendly: that is adding a new vlan doesn't require planning and it can be done without impact on the production network.
Bpdu filter:
blocks sending of BPDUs out of a port.
never use it on access port of an enterprise it is useful only for service providers to avoid to join their STP with customer's STP.
bpdu guard:
the right tool for access ports in enterprise:
if a bpdu is received on the port the port is placed in error disable.
This can detect users connecting unauthorized switches to the network.
Hope to help
Giuseppe
10-14-2009 10:17 PM
Hi,
Is bpduguard a global command. On interface of switch I can configure as
interface fa0/1
switchport mode access
switchport access vlan 2
spanning-tree portfast
If a router/switch is connected to fa0/1
then the port gets disabled.
What happens if a bridge is connected to this port.
10-14-2009 10:27 PM
bpduguard can be configured globally or per interface:
glogally:
Causes all PortFast-configurd interfaces to become in error-disabled state if they receive a BPDU frame.
Switch(config)# spanning-tree portfast bpduguard default
Per interface:
Causes one interface to become in error-disabled state if it receives a BPDU frame.
Switch(config-if)# spanning-tree bpduguard enable
10-14-2009 10:57 PM
This is very helpful.
what happens if a Cisco WLAN access-point is connected.
BackboneSwitch====connected=====EdgeSW
int gi0/10
switchport trunk encap dot1q
switchport mode trunk
Are there any other best-practice configuration to have on trunk interfaces
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