09-23-2009 10:34 AM - edited 03-06-2019 07:51 AM
I am curious if there is a way to block loops between ports.
Here is a situation:
client orders 3 network lines. they decide to plug all three lines into an unmanaged switch that they did not inform us about.
I am guessing that storm-control broadcast level x is my best option and use errdisable detect storm-control enabled without errdisabled storm-control recovery enabled.
Edge switches are 3560 running 12.2(44)SE1
Here are some snippets from and edge switch config:
#sh spanning-tree summary
Switch is in rapid-pvst mode
Root bridge for: VLAN0201
Extended system ID is enabled
Portfast Default is disabled
PortFast BPDU Guard Default is disabled
Portfast BPDU Filter Default is disabled
Loopguard Default is enabled
EtherChannel misconfig guard is enabled
UplinkFast is enabled but inactive in rapid-pvst mode
BackboneFast is disabled
Configured Pathcost method used is short
Guest port setting:
interface GigabitEthernet0/1
description port1
power inline never
switchport access vlan 24
switchport mode access
switchport port-security
switchport port-security aging time 5
switchport port-security violation restrict
srr-queue bandwidth limit 10
priority-queue out
no mdix auto
storm-control broadcast level 10.00
storm-control multicast level 40.00
storm-control action shutdown
storm-control action trap
macro description ROLLBACK
no cdp enable
spanning-tree portfast
spanning-tree bpdufilter enable
spanning-tree bpduguard enable
spanning-tree guard loop
ip dhcp snooping limit rate 90
end
Thanks,
Eric
09-23-2009 10:45 AM
Hello Eric,
I strongly recommend to remove the following line:
spanning-tree bpdufilter enable
this can cause only problems here.
have two links with STP bpdu filter enabled and you are in good position to get a loop.
spanning-tree bpduguard + broadcast storm-control
spanning-tree loop guard looks for the opposite events in comparison to STP bpdu guard.
BPDU guard reacts to the fact of receiving unexpected BPDUs on a port.
BPDU root guard can be of help instead of BPDU guard if you need to connect a third-party switch to the port.
BPDU root guard reacts to receiving BPDUs that would cause a change of Root Bridge ID.
BPDU loop guard reacts to the fact that BPDUs stop to be received on an uplink by putting the port in inconsistent state instead of moving the port to forwarding state.
so the right tool if a switch will be connected should be root guard.
loop guard is useful on uplinks.
on user ports bpdu guard
Hope to help
Giuseppe
09-23-2009 10:55 AM
Thanks, I will update all our guest ports
Discover and save your favorite ideas. Come back to expert answers, step-by-step guides, recent topics, and more.
New here? Get started with these tips. How to use Community New member guide