kloppyo wrote: » I noticed you are not planning on using any of the course books (OCG or FLG). I was wondering is because the e-learning contains all the same material as those books and is a comprehensive overview of the info required to help pass the exam? Thanks
MustafaIT wrote: » I hope we can pass after 3 months. Good luck
clarson wrote: » hello every one, I'm studying for the switch exam also. I came across a question about the implementation of where to place stp root guard. But I've gotten different answers. So, lets discuss it and get an answer for everyone. What I've been able to find out is this: 1) enable root guard on all ports where the root bridge should not appear. this would mean all access ports. And, access ports should set up with portfast and bpduguard. This leaves all the links and that won't allow stp to reconverge if there is a root failure 2) enabled on all the designated interfaces. again how does this effect reconvergance if there is a root failure 3) portfast/bpduguard on all access ports and root guard on ports towards the customer (other organization). no where else in your environment. inside your own network, using Root Guard is a questionable practice. Your network can be considered trustworthy and there is no rogue root switch to protect against. Using Root Guard in your own network could cause your network to be unable to converge on a new workable spanning tree if any of the primary links failed, and it would also prevent your network from converging to a secondary root switch if the primary root switch failed entirely. 4) at the distribution layer facing the access layer. no access layer switch can become the root bridge and only distribution and core layer switches can. and core switches probably aren't running stp. if the links between the HSRP primary and standby fails. The access switches are sending superior BPDUs but the secondary distribution switch will block the link due to Root Guard being implemented. This means that any traffic arrivingat the secondary distribution switch destined for the access layer switches will be black holed. so what are your thoughts on this?
negru_tudor wrote: » It all comes down to policy: what and how you want / need things implemented in your environment. Points 3 and 4 are kind of accurate but also leave it up to you to make up your mind depending on the environment you're in. From STP's perspective, one thing to note at point 4 is that even if the link between your HSRP nodes fails the topology can reconverge and redundant paths are put into forwarding state. Your topology would look like an N for example. Not sure why you would have those access switches even send out superior BPDUs. Usually you'd hardcode the priority on your root and backup root nodes to something low enough (4096 or 8192) that the access switches will not be able to beat by default (32768 ). You wouldn't need Root Guard if you wouldn't have a trust boundary in your switched topology (ex. interconnect to another vendor or department's switched/L2 topology); working around wacky STP elections can be done if you're deliberately assigning STP priorities on your root/backup root nodes. Root Guard as a concept in itself makes sense and can easily be labed / observed but the use cases really depend on what your requirements are and environment looks like.
clarson wrote: » yes, it does seem to be very dependent on the topology. which makes it a good test question. there isn't just one answer. Your given a topology. now do you know what you are doing.