Hi, Have a client with 2 x 6500/720 Collapsed Core Dsitribution and 60+ legacy access switches. The legacy access switches provide a loop free topology (normally!)and the client is keen to disable Spanning Tree. I'm not happy with this and would prefer spanning tree enabled even in the absence of a looped topology. What are your views, is the Cisco recommendation to always enable STP?
Not running spanning tree at all is asking for it. If every port was a routed port including all the edge ones then I would do it.
Even if you configure everthing perfectly some stupid user will get you. All they need to do is plug a cross cable between 2 ports and that vlan is gone. HP switches and many consumer ones will now auto negotiate the straight/cross cable. So users can loop your network with straight cable.
If there is no redundancy in the network, you can have them enable portfast everywhere. A simple global command, spanning-tree portfast default, allows you to do that (well, it will still have to be manually configured on trunks). This way, you will keep the simple behavior and immediate convergence speed of a network without spanning-tree, while keeping spanning-tree in case of a configuration error (bad cabling etc...). If the number of vlans is an issue (cat6k supports thousands of vlans even in PVST mode, check the release notes), you can simply switch to MST mode. Again, if there is no redundancy in the network, there is no need for any STP configuration.
If they really don't want STP after that, it's purely for religious reasons... Some people are convinced STP creates bridging loops, maybe it's not a bad idea to let them disable it and check by themselves;-)
Thanks for all the replies. For clarity I should have said that the legacy access switches are non Cisco with dual uplinks from either single access or dual access switches. They support a L2 link failover feature that does not rely on spanning tree. My concern is if that feature fails or a patching error occurs then spanning tree saves the day. There are approx 100 vlans so no problem with pvst mode.
This is actually a pretty cool feature, i didn't even know it existed until I was looking for a solution to advertise a subnet (prefix in BGP talk), only if a certain condition existed. This is exactly what conditional advertisements does
j ai une question j ai achete un routeur cisco 887VA-k9 , je le configuré avec la configuration ci- dessous
si je le lier avec mon pc portable sur l un de ses ports directement ça marche toute est bien ( la connexion internet + m...
Attached policy provides CLI access to the Cisco 4G router over text messaging. Two files are in the attached .tar file:
2. PDF with instructions on how to load and use the .tcl file.