By default, interfaces on most Cisco switches are set to dynamic desirable mode. (Catalyst 2950 and 3550 switches.) Desirable mode will create a trunk link if the neighboring interface is set to desirable, trunk, or auto mode. Because both interfaces by default are in desirable mode, this means a link between two Cisco switches will automatically become a trunk link unless configured otherwise. It is reccomended that all switch ports be set to access mode for security.
I have found this note in the book "Cisco field manual: Catalyst switch configuration" by Hucaby and McQuerry:
"Cisco 2950 and 3500XL switches do not support DTP and are always in a mode similar to nonegotiate.If you turn trunking on for one of these devices, it will not negotiate with the other end of the link and requires that the other link be configured to on or nonegotiate."
I imagine that this note come from a real world experience, also because the 2950 official configuration guide says that the default should be dynamic desirable.
That is incredible! Is it possible that also the official document is not clear about this argument?
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.