[c-nsp] Cisco RSTP interop with 802.1w equipment
Phil Bedard
philxor at gmail.com
Sat Oct 17 19:19:52 EDT 2009
If you change the native VLAN on the cisco, it will still only send to
the IEEE STP MAC on VLAN 1. If you were using PVST+ on the Cisco
changing the native vlan will tell it to send PVST+ BPDUs to the Cisco
MAC untagged on that VLAN.
Phil
On Oct 16, 2009, at 7:45 AM, Marian Ďurkovič wrote:
> On Fri, Oct 16, 2009 at 12:06:39PM +0100, Phil Mayers wrote:
>>> Aren't Cisco switches supposed to send BPDUs also to IEEE STP MAC
>>> address
>>
>> Generally, no. Vlan 1 is treated specially.
>>
>>> on 802.1Q trunks? Or is there any special config needed for this?
>>
>> Vlan number 1 will interop, so if you do this:
>>
>> int Gi1/1
>> switchport mode trunk
>> switchport trunk native vlan 1
>> switchport trunk allowed vlan 1,2,3
>>
>> ...then vlan 1 will form an 802.1w adjacency with the neighbour,
>> vlans 2
>> and 3 will just pass straight through it.
>
> Is that ultimately limited to vlan #1, or could it be done with the
> native
> vlan on trunk (e.g. vlan #1520) as well?
>
> We're removing vlan #1 from all trunks by principle for obvious
> reasons...
>
> Thanks & kind regards,
>
> M.
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