I assume that this is a trunk link (802.1Q or ISL) that the Sniffer is connected to. Those are Per VLAN Spanning Tree+ (PVST+) BDPUs which are sent every hello time which by default is 2 seconds. If you have x VLANs, you will see (x-1)/2 PVST+ BPDUs every second. So if you have 100 VLANs you will see 49.5 PVST+ BPDUs/second on a trunk link
BPDUs on VLAN 1 are addressed to 0180C2000000 (this is the well known MAC address for IEEE STP BPDUs) which ths Sniffer is able to decode.
BPDUs on all other VLANs (if using PVST+, which is the default STP mode) are addressed to 01000CCCCCCD (this is the MAC address used by Cisco for PVST+ BPDUs). These packets are 802.1Q tagged and the Sniffer is probably not able to decode. Note that the SNAP type for PVST+ BPDUs is 0x0104.
In my previous posting, I stated that the SNAP type for PVST+ BPDUs is 0x0104 (which was not correct). 0x0104 is the SNAP type for PAgP frames. The SNAP type for PVST+ BPDUs is 0x010b (consistent with what was stated in the original posting)
We have 3 identical switches configured by someone else and would like to claim some of the Gigabit ports(G1/G2/G3/G4) for use on servers. When we try to change the wiring and configuration, we run in to connectivity issues. Attached is a des...
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...