MSTP BPDUs are sent untagged on 1Q trunk (I'm trying to avoid the term native vlan, which is not exactly correct). On ISL links, they are sent on vlan 1 afaik.
Rapid-PVST, which is the PVST version of RSTP, is sending one BPDU per vlan. The BPDU for vlan 1 is sent untagged on 1Q trunks (with the regular IEEE STP mac address as a destination), while the other vlans (!=1) have their BPDUs sent tagged, to a cisco proprietary mac address.
On ISL trunks, the BPDUs for all the vlans are sent in their respective vlan, with the IEEE mac address as a destination.
Untagged frames are not really sent on a "native vlan", they just don't have an 802.1Q header. If you want, vlans are just an additional layer on the top of the mac layer. Not a great analogy, but for instance, UDP works on the top of IP and you don't call an IP packet a "native UDP frame";-)
Bridges that are not 1q capable just ignore the 1q tag, while 1q bridges classify the untagged frames they receive in a given vlan. STP untagged control frames are received by the control protocol even before the switch gets to classify untagged frames into a particular vlan. That's why I would not say they belong to "the native vlan" (btw, the concept of a unique native vlan is Cisco specific, in theory several vlans could be sent untagged on a particular port).
Hi everyone, I would like to thank you in advance for any help you can provide a newcomer like myself!
Im studying the 100-105 book by Odom and am currently on the topic of Port security. I purchased a used 2960 and I'm trying to follow a...
While deploying a number of 18xx/2802/3802 model access points (APs), which run AP-COS as their operating platform. It can be observed on some occasions that while many of their access points were able to join the fabric WLC withou...
I am going to design and build an LAN network under a tunnel underground with long distance between the switches.
I will have 2 Catalyst switches and 8 Industrial IE3000, and they will be connected with fiber.
For now I am planning on use Layer-2 s...