all links begin forwarding immediately then it would save time to configure globally correct? Yes if you configure it globally then all non-trunked links would be enabled for portfast, as for if you would use it in the lab comes to down to what the question says. For example if the question says put all access intefaces into portfast with a single command then you would use global
The differences are that globally it only works for port-fast enabled ports, but when configured on the interface it is on unconditionally, correct? Yes the global macro command enables BPDUguard on portfast enabled interfaces, again the language would either be use one command or as few commands as possible, it would be port config if it just wants a couple ports. Bpdufilter is basically the same logic as above, technically you're not disabling spanning tree on the port but you are filtering the bpdus so in effect your blocking spanning tree communication on router ports which would only be a concern if you are running a bridge on the router. Loopguard is the same kind of idea as UDLD, both detect unidirectional type problems the difference is Loopguard uses BPDUs to verify communication and is good for detecting STP software errors and UDLD uses its own protocol and is good for detecting things like fiber issues. Cheers, Donald Robb Productive Networks / Network Consultant ______________________________________________________________ CCIE Written, CCIP, CCSP, CCDP, CCNP, CCNA: Voice, JNCIP, SCP, MCSA 2003, Security+, CCSE.R65, PACE Experts-Exchange: Guru - R&S -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of marc abel Sent: Sunday, November 20, 2011 12:28 PM To: [email protected] Subject: [OSL | CCIE_RS] Spanning-tree options clarifications I have a hard time keeping some of the spanning-tree options straight, and would like to clarify that my current understanding is correct. You can configure portfast globally or per interface. These seem to be functionally identical, is this correct? So if my lab were to say make sure that all links begin forwarding immediately then it would save time to configure globally correct? Is this what you guys do? You can configure BPDU guard globally or per interface. The differences are that globally it only works for port-fast enabled ports, but when configured on the interface it is on unconditionally, correct? What language might lead you to choose one over the other? You can configure BPDU filter globally or per interface. The difference is that globally it only works for port-fast enabled ports, and it still sends a few bpdu's on startup. Configured locally it unconditionally enables on the port and it sends no BPDU's, correct? So I can see a scenario were they ask that NO bpdu's are sent or recieved, in this case you would have to configure on the port right? What language might they use if they wanted you to configure globally? I understand that functionally enabling bpdu filtering is the same as disabling spanning-tree on the port, something to watch out for. Also if anyone can provide further clarification on loopgaurd I would appreciate it. I read the sectio in the 3560 config guide but it still doesn't make sense to me, Thank you, Marc _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com Are you a CCNP or CCIE and looking for a job? Check out www.PlatinumPlacement.com To Unsubscribe from this list please visit the following link and follow the directions to unsubscribe. http://onlinestudylist.com/mailman/listinfo/ccie_rs
