[nsp] VLAN settings on 2950s/2610s

[Jack.W.Parks at alltel.com]

The native VLAN is untagged.  Either place your VLAN1 configs on the
physical interface or change the native VLAN on the switch to something
different. 

EXAMPLE 1(change router): Placing your VLAN 1 (or any untagged VLAN)
configuration under the physical interface.

interface FastEthernet0/0
 description VLAN 1
 ip address 1.1.1.1 255.255.255.0
 speed 100
 full-duplex
!
interface FastEthernet0/0.10
 description VLAN 10
 encapsulation dot1Q 10
 ip address 10.10.10.1 255.255.255.0

EXAMPLE 2(change switch):  Changing the native VLAN to something
different than VLAN1 - VLAN1 will now be tagged and you can place it
under a subinterface (like you are trying to do). 

interface FastEthernet0/9
 description 2950 Switch w/ new native VLAN
 switchport trunk native vlan 900
 switchport mode trunk
 no ip address



Jack W. Parks IV
Sr. Network Engineer
ALLTEL Communications
jack.w.parks at alltel.com
Work: 501-905-5961
Cell: 501-680-3341

-----Original Message-----
From: Security [mailto:security at cytanet.com.cy] 
Sent: Saturday, May 10, 2003 1:48 PM
To: Sharan Harkisoon
Cc: cisco-nsp at puck.nether.net
Subject: Re: [nsp] VLAN settings on 2950s/2610s


The use of the native command did not help. I used it on the
subinterface of the cisco2610 and also on the trunk port on the switch.
The only way to make trunking work was to configure two VLANs on the
2950 switch without using VLAN1. I am thinking to proceed and upgrate
the switch software and/or the router IOS to see what will happen.


>This is correct, I've had this issue when switching from a 7206 to a 
>3620. I think the the 7206 didn't require "native" on the VLAN1 
>interface, and worked fine.  Could have been a firmware issue.
>
>Just make sure to add the "native" command on the end like Ryan 
>suggested.
>
>interface FastEthernet4/0.1
> encapsulation dot1Q 1 native
>
>
>Sharan
>
>----- Original Message -----
>From: "Ryan O'Connell" <ryan at complicity.co.uk>
>To: <security at cytanet.com.cy>; <cisco-nsp at puck.nether.net>
>Sent: Friday, May 09, 2003 10:25 AM
>Subject: Re: [nsp] VLAN settings on 2950s/2610s
>
>
>> At 09/05/2003 16:12, Security wrote:
>> >I spend several hours working with catalyst2950 switch and a 
>> >Cisco2610 router trying to configure VLAN trunking using 802.1q. I 
>> >Discover that
>when
>> >one of the VLANs is the default (VLAN1) trunking is not working. 
>> >Using other vlans e.g vlan2 and Vlan3 trunking is working perfectly.
According
>to
>> >Cisco Documentation trunking should also work with VLAN1 as one of 
>> >the VLANs.
>> >
>> >Can anyone advise? I am thinking of a bug on the software of the 
>> >switch
>but
>> >your advice will be appreciated
>>
>> Make sure you have Native (default) VLANs set properly both sides - 
>> switches have a default native VLAN and router don't. Anything in the

>> native VLAN doesn't get tagged when being sent out, so the router 
>> will
>drop
>> it when receiving it unless one subinterface has been marked 
>> "native".
>>
>>  From memory, by default on the 2950 the default native VLAN is 1 so 
>> you need to make sure you use "encapsulation dot1q 1 native" on the 
>> 2610 for the appropriate subinterface. (This is from memory though, I

>> may have it
>wrong)
>>
>> _______________________________________________
>> cisco-nsp mailing list  cisco-nsp at puck.nether.net 
>> http://puck.nether.net/mailman/listinfo/cisco-nsp
>> archive at http://puck.nether.net/pipermail/cisco-nsp/
>>
>
>
>
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