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native vlan vs vlan 1

Hi

I have a few switches ( let's say 3550/3560) with all port as a trunk. On every port i have different native vlan, other than 1. What tag, on trunk ports,  switch uses for transmit normal STP frames ? or VTP, LACP, PaGP ? It's vlan 1 ? i have to have vlan 1 on my trunks as tagged ? I'm just wondering about that. Thanks for explanation.

4 REPLIES
VIP Super Bronze

native vlan vs vlan 1

Vlan 1 can not be deleted.  It can only be disabled, but even when it is disabled, it continues to send and receiver control protocols such as CDP, VTP, PAGP, etc...

HTH

Silver

Re: native vlan vs vlan 1

Hello Peter, Reza, Milan

Thanks for your inputs. Allow me also to add this link regarding specifities between STP IEEE/[R]PVST+ in regards to the native vlan (VLAN1 or not).

http://www.cisco.com/en/US/tech/tk389/tk621/technologies_tech_note09186a00801d11a0.shtml#topic1

This list shows how (R)PVST+ interoperates with IEEE 802.1Q or IEEE 802.1D =>

If the Native VLAN on an IEEE 802.1Q trunk is VLAN 1:

  • VLAN 1 STP BPDUs are sent to the IEEE STP MAC address (0180.c200.0000), untagged.
  • VLAN 1 STP BPDUs are also sent to the PVST+ MAC address, untagged.
  • Non-VLAN 1 STP BPDUs are sent to the PVST+ MAC address (also called the Shared Spanning Tree Protocol [SSTP] MAC address, 0100.0ccc.cccd), tagged with a corresponding IEEE 802.1Q VLAN tag.

If the Native VLAN on an IEEE 802.1Q trunk is not VLAN 1:

  • VLAN 1 STP BPDUs are sent to the PVST+ MAC address, tagged with a corresponding IEEE 802.1Q VLAN tag.
  • VLAN 1 STP BPDUs are also sent to the IEEE STP MAC address on the Native VLAN of the IEEE 802.1Q trunk, untagged.
  • Non-VLAN 1 STP BPDUs are sent to the PVST+ MAC address, tagged with a corresponding IEEE 802.1Q VLAN tag.Note: Native VLAN STP BPDUs are sent untagged.

Best regards.

Karim

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