I am using two cisco L2 switches. Both are connected by a trunk link. Unfortunately I configured different native vlan between two switches. Suddenly I got an error that native vlan mismatch. When I changed the configuration Now it's working fine. My question is that how one switch identify that native vlan mismatch(either by Bpdu, cdp or packet). Please mention which of the following used by switch to identify native Vlan mismatch.
Yes, and STP as well if you run a trunk between the two switches. PVST+ and RPVST+ BPDUs have a TLV in their trailer that carries the VLAN number for which the BPDU was originated. If the BPDU is received in a different VLAN (caused by a native VLAN mismatch), the receiving switch will be able to detect it.
Wireshark 1.12.x will be capable of displaying this TLV field in captured PVST+ and RPVST+ BPDUs. Until 1.12.x is released, you may want to try daily builds from:
CDP performs the detection on its own, independently of STP. If you disabled STP, CDP would still detect the mismatch and report it. However, as opposed to STP, CDP would take no action, while STP would block the offending pair of VLANs.
The STP-based detection works only on trunks where BPDUs for multiple VLANs are potentially sent and received. If the link interconnecting the switches operated as an access link, STP would use a standard BPDU format without the ability to detect native VLAN mismatches.
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.