From: Brant I. Stevens (branto@branto.com)
Date: Tue Feb 21 2006 - 14:15:14 GMT-3
I'd imagine that traffic on the native VLAN would be passing, but I don't
think this is a case of trunking occurring between the 2 protocols, as
someone else said, they have different frame formats.
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Brantley, Charles
Sent: Tuesday, February 21, 2006 11:51 AM
To: Ivan; ccielab@groupstudy.com
Subject: RE: OT: dot1Q and ISL
Well, somehow it is configured in my network. Just to let you know, before
I got here....
I just implemented syslogging, and I am receiving these messages:
2006 Feb 21 10:49:24 CST -06:00 %SPANTREE-2-RX_1QNON1QTRUNK: Rcved 1Q-BPDU
on non-1Q-trunk port 3/6 vlan 4
2006-02-21 08:30:00 2006 Feb 21 08:57:22 CST -06:00
%SPANTREE-2-RX_1QNON1QTRUNK: Rcved 1Q-BPDU on non-1Q-trunk port 3/7 vlan
999
Look up what they meant, and Cisco reports that trunks are configured
different on each end.
%SPANTREE-2-RX_1QNON1QTRUNK: Rcved 1Q-BPDU on non-1Q-trunk port
[chars] vlan [dec] from [chars]
This message indicates that the non-1Q-trunking (ISL) port has received at
least one 1Q-tagged spantree BPDU frame on the receiving VLAN. [dec] is the
module number, [chars] is the port number, [dec] is the VLAN number, and the
second [chars] is the source MAC address of the BPDU.
Recommended Action: Either reconfigure the non-1Q-trunking port into a
1Q-trunking port, or reconfigure the peer 1Q-trunking port into the
corresponding non-1Q-trunking port.
Does anyone know what would happen if this is the case...what traffic would
get passed and/or dropped...? I am not receiving any complaints about
problems so I am assuming something is working correctly.
Chuck Brantley
-----Original Message-----
From: Ivan [mailto:ivan@iip.net]
Sent: Tuesday, February 21, 2006 10:44 AM
To: ccielab@groupstudy.com; Brantley, Charles
Subject: Re: OT: dot1Q and ISL
no.
It's impossible.
Size dot1q tag is 4 bytes
ISL - 20 byte
And different algoritm used to encapsulate payload.
ISL: there is header and footer(CRC) for payload packet.
dot1q: this tag inject after src dst mac addreses and before remain packet.
> Is it possible to have to switches trunking with one another using
> dot1q on one side and ISL on the other...?
>
> i.e
> SW1 port 3/6 (ISL) --> SW2 port 1/2 (dot1Q)
>
> Thanks
>
> Chuck Brantley
>
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-- Ivan
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