RE: 3550 reconciling requirement to solution

From: asadovnikov (asadovnikov@comcast.net)
Date: Wed Oct 01 2003 - 21:51:19 GMT-3


It looks like they are making native VLAN 999, which does not exist in the
scenario nor is permitted on the trunk. Sloppy solution if you ask me, but
shall work.

Best regards,
Alexei

-----Original Message-----
From: ccie2be [mailto:ccie2be@nyc.rr.com]
Sent: Wednesday, October 01, 2003 8:27 PM
To: Group Study; asadovnikov
Subject: Re: 3550 reconciling requirement to solution

I'm sorry. I clicked "send" too soon and forgot to include the solution. I
sent the solution right afterwards. And, in the solution, there's no
command like "dot1q tag native".

interface Port-channel1
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 999
 switchport trunk allowed vlan 1,10,20,30,40,55,70,100 switchport mode
trunk no ip address

interface FastEthernet0/23
 switchport trunk encapsulation dot1q
 switchport trunk native vlan 999
 switchport trunk allowed vlan 1,10,20,30,40,55,70,100 switchport mode
trunk no ip address udld enable channel-group 1 mode on ! interface
FastEthernet0/24 switchport trunk encapsulation dot1q switchport trunk
native vlan 999 switchport trunk allowed vlan 1,10,20,30,40,55,70,100
switchport mode trunk no ip address udld enable channel-group 1 mode on

----- Original Message -----
From: "asadovnikov" <asadovnikov@comcast.net>
To: "'ccie2be'" <ccie2be@nyc.rr.com>; "'Group Study'"
<ccielab@groupstudy.com>
Sent: Wednesday, October 01, 2003 6:59 PM
Subject: RE: 3550 reconciling requirement to solution

There is a command on 3550 ("dot1q tag native" or something alone this
lines) which will make 3550 to send frames on the native VLAN of dot1q trunk
with the tug.

Best regards,
Alexei

-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
ccie2be
Sent: Wednesday, October 01, 2003 6:30 PM
To: Group Study
Subject: 3550 reconciling requirement to solution

Hi,

2 3550's are connected back to back via Fa0/23 and 0/24 ports on both Cat's.

The requirement is this:

Config the 2 interfaces (Fa0/23 and Fa0/24) connecting the 3550's to appear
as 1 link to STP....

This link should allow all vlan's to travel across with their vlan ID
intact. You can not use Cisco's proprietary protocol to achieve this. Every
packet that traverses the link must have the vlan ID, no exceptions.

I'm OK with everything except the last 2 words, "no exceptions". Since we
can't use ISL, 802.1q has to be used, but that means packets in the native
vlan aren't tagged and thus don't have a vlan ID. The solution is below,
but I'm hoping someone can explain how that solution meets the above
requirement and maybe what would be a good way to think through this
problem.

Thanks, dt

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