Lets assume there is a following setup: http://img844.imageshack.us/img844/9133/stp.png
ISP manages "R1", "C3550-24-A", "C-355-24-B" and "C2950-24-A". "Customer-SW" is fully under customer control. As you can see, there are two paths to "Customer-SW". What are the risks with such setups in general? I'm able to name two disadvantages: 1) in case customer configures (accidentally) "spanning-tree bpdufilter enable" on his ports Fa0/23 - 24 there will be L2 loop which causes very high PPS and CPU load in ISP devices 2) in case customer switch is a STP root(it's easy to become root switch by changing priority when "root guard" on ISP side is not configured) and customer VLAN is through many ISP switches, non-optimal paths for traffic can take place Are there some other possibilities for L2 loop? Or anyone seen a hub/switch which handles 802.1d/802.1w BPDU's somewhat abnormally and might create a L2 loop(under certain circumstances)? Any other disadvantages which might arise with setups like this? regards, martin _______________________________________________ cisco-nsp mailing list [email protected] https://puck.nether.net/mailman/listinfo/cisco-nsp archive at http://puck.nether.net/pipermail/cisco-nsp/
