What kinds of ports are VTP frames sent out of?

[Sam Brynes]

I'm playing around with PVLANs. I have two layer 3 switches connected with an Ethernet cable. The port on switch "A" has the private VLANs. Switch "B" is configured as a host, so I set its port as a layer 3 routed port ("no switchort"). Switch "A" is configured as a private VLAN host port (not promiscuous) and for a secondary community PVLAN.

I'm running VTP version 3 between the two switches, The single Ethernet cable is the only cable between the two switches.

Is switch "A" send out VTP frames over the link, and switch "B" ignoring them in this scenario since B's port is a routed port? And switch "A" is sending them out since it's a private VLAN (layer 2) port?

[Reza Sharifi]

Have a look at this document.

VTP Messages in Detail

VTP packets are sent in either Inter-Switch Link (ISL) frames or in IEEE 802.1Q (dot1q) frames. These packets are sent to the destination MAC address 01-00-0C-CC-CC-CC with a logical link control (LLC) code of Subnetwork Access Protocol (SNAP) (AAAA) and a type of 2003 (in the SNAP header). This is the format of a VTP packet that is encapsulated in ISL frames:

Link:

https://www.cisco.com/c/en/us/support/docs/lan-switching/vtp/10558-21.html

HTH

[Sam Brynes]

Thanks. I wonder if it still sends these frames out a routed port? If the port is a layer 2 access port, I wonder how a switch will process it if it is VLAN tagged?

[paul driver]

Hello

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@Sam Brynes wrote:

Thanks. I wonder if it still sends these frames out a routed port? If the port is a layer 2 access port, I wonder how a switch will process it if it is VLAN tagged?

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vtp is a L2 feature it wont traverse a L3 interface.

[paul driver]

Hello

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@Sam Brynes wrote:

I'm running VTP version 3 between the two switches, The single Ethernet cable is the only cable between the two switches.

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On a side note - What mode is it in, If i remember correctly the switches needs to be transparent when running with PVLANS