From: Reza Toghraee (reza@toghraee.com)
Date: Wed Oct 22 2008 - 18:50:12 ARST
Ok let me lab it up.
R1(f0/0)----VLAN100------(f0/1)_SW1_(f0/13)---.1Q_Native_100-------------.1Q
_Native_200--(f0/13)_SW2_(f0/2)------VLAN200----(f0/0)R2
Rack1R1(config-if)#do shr int f0/0
interface FastEthernet0/0
ip address 10.0.0.1 255.255.255.0
end
Rack1R2(config-if)#do shr int f0/0
interface FastEthernet0/0
ip address 10.0.0.2 255.255.255.0
end
SW1
interface FastEthernet0/1
switchport access vlan 100
switchport mode access
!
interface FastEthernet0/13
switchport trunk encapsulation dot1q
switchport trunk native vlan 100
switchport mode trunk
!
SW2
interface FastEthernet0/2
switchport access vlan 200
switchport mode access
end
!
interface FastEthernet0/13
switchport trunk encapsulation dot1q
switchport trunk native vlan 200
switchport mode trunk
end
04:28:51: %SPANTREE-2-RECV_PVID_ERR: Received BPDU with inconsistent peer
vlan id 100 on FastEthernet0/13 VLAN200.
04:28:51: %SPANTREE-2-BLOCK_PVID_LOCAL: Blocking FastEthernet0/13 on
VLAN0200. Inconsistent local vlan.
%CDP-4-NATIVE_VLAN_MISMATCH: Native VLAN mismatch discovered on
FastEthernet0/13 (100), with Rack1SW2 FastEthernet0/13 (200).
Oops, lets disable spanning-tree for vlan 200 on sw2 and vlan 100 on SW1
and CDP
SW1: no spanning-tree vlan 100
SW2: no spanning-tree vlan 200
SW1,SW2: no cdp run
Rack1R1#ping 10.0.0.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 10.0.0.2, timeout is 2 seconds:
.!!!!
Success rate is 80 percent (4/5), round-trip min/avg/max = 1/2/4 ms
Rack1R1#
Finish, no need to use "switchport nonegotiate" you are correct :)
Reza
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Scott M Vermillion
Sent: Thursday, October 23, 2008 12:28 AM
To: 'Reza Toghraee'; mihai.grigore@onlinehome.de; ccielab@groupstudy.com
Subject: RE: Re: Vlan dot1q tag Native
Hey Reza,
Here is the interface config from the little lab test I just posted
(should've included this output to begin with):
SW1#sh run int fa0/7
Building configuration...
Current configuration : 94 bytes
!
interface FastEthernet0/7
switchport trunk encapsulation dot1q
switchport mode trunk
end
So at least with my version of code and my hardware platform, 'switchport
nonegotiate' wasn't necessary (and that kind of makes sense if you think
about it - as long as both ends are hard-coded for 'mode trunk' there
shouldn't be any issues whether 'nonegotiate' is configured or not).
SW1#sh ver | inc image
System image file is
"flash:c3560-advipservicesk9-mz.122-40.SE/c3560-advipservicesk9-mz.122-40.SE
.bin"
Cheers,
Scott
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of Reza
Toghraee
Sent: Wednesday, October 22, 2008 1:06 PM
To: mihai.grigore@onlinehome.de; ccielab@groupstudy.com
Subject: RE: Re: Vlan dot1q tag Native
Mihai,
I did this long time ago.
It will work if :
1) disable DTP, trunks must be ON, and on no negotiate
2) disable spanning-tree
I don't remember exactly about spanning tree, but I think you must remove
the instance for both native vlans on both switches.
Reza
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
mihai.grigore@onlinehome.de
Sent: Wednesday, October 22, 2008 10:47 PM
To: ccielab@groupstudy.com
Subject: Re: Re: Vlan dot1q tag Native
Guys,
GREAT EXPLANATION !! Worth much more than the one in DOCCD... I read that
one
several times but did not get it... Now, I feel better about the native
vlan.
I have a question though: is it possible to configure different native VLANs
on
the ends of a trunk between Cisco switches ?
As far as I could see in the lab, as soon as I configure one end, the trunk
is
brought down and an error message pops up, something like: "native VLAN
mismatch... bringing down the trunk".
After I configure the SAME native vlan on the other end of the trunk, this
comes up. As far as I know, this is transmitted via CDP.
I guess scenario 3 does not work with Cisco switches. Maybe between Cisco
and
non-Cisco or between non-Ciscos...
TIA, Mihai
Blogs and organic groups at http://www.ccie.net
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