From: Carter, Lee (Lee.Carter@CommerceBank.com)
Date: Sat Sep 13 2003 - 14:55:29 GMT-3
To answer the first question below:
SW1 --- (ISL) ---- SW2 ---- (DOT1.Q) ----- SW3
(server) (client) (client)
same vtp domain.
Yes this configuration works just fine. The only special consideration I can
think of (but you wouldn't see this on the lab)..
SW1 - Cisco Device (has to be (ISL)
Sw2 - Cisco Device (has to be (ISL)
SW3 - NON Cisco device (like some bay piece of @!@#$%)
The Dot1.q trunk link between SW2 and SW3 will only have one instance of
vlan spanning tree for any and all vlans that are trunked across it. If a
single vlan were to bounce on SW3 it would send one TCN (topology change
notification) to Sw2 without a specific VLAN (since it does not support per
vlan spanning-tree) SW2 would then send out a TCN for each and every vlan to
SW1 since it does not know which vlan bounced on SW3. (I have seen this in 3
different large networks and this has caused serious layer 2 outages).
My suggestion to fix this would be to run a layer 3 link between SW2 and SW3
and stop the trunking or to use the same vendor throughout.
-----Original Message-----
From: MADMAN [mailto:dmadlan@qwest.com]
Sent: Friday, September 12, 2003 3:34 PM
To: ccie2be
Cc: Group Study
Subject: Re: VTP and ISL and 802.1q trunks
I know I have both encap types on the same swithes in the lab and
some customers have both encaps, ISL from legacy days and 802.1q cause
some platforms only support dot1q.
I can't honestly say I recall a setup as you describe but I think it
would work. Would I do this for a customer, no.
HTH
Dave
ccie2be wrote:
> Hey Dave,
>
> Thanks for getting back to me.
>
> Are either of the below scenarios, scenarios that you've actually
> implemented and know from 1st hand knowledge?
>
> If you were able to implement the 1st scenario, did you do any vlan load
> balancing between the 2 switches, for example, make sw1 the root for vlan
> 1,3, and 5 and make sw2 the root for vlan 2,4, and 6.
>
> Also, I've got one more interesting scenario regarding VTP and trunking.
>
> Sw1 -----ISL trunk------router--------802.1q trunk----------Sw2
>
> Assume Sw1 is a VTP server and Sw2 is a VTP client. On the router, the 2
> fast ethernet interfaces are bridged together. Q? Do VTP frames transit
> the router from Sw1 to Sw2 and enable Sw2 to be in the same VTP domain as
> Sw1?
>
> Q? If this doesn't work when the 2 trunks are different, like above, will
> it work if the 2 trunks are ISL? 802.1q?
>
> As you say, in a production network, it would be better for both trunks to
> be the same, but Cisco doesn't care about that in the lab.
>
> dt
>
>
> ----- Original Message -----
> From: "MADMAN" <dmadlan@qwest.com>
> To: "ccie2be" <ccie2be@nyc.rr.com>
> Cc: "Group Study" <ccielab@groupstudy.com>
> Sent: Friday, September 12, 2003 12:57 PM
> Subject: Re: VTP and ISL and 802.1q trunks
>
>
>
>> no though I tend to use 802.1q, try to keep configs consistant.
>>
>> Dave
>>
>>ccie2be wrote:
>>
>>
>>>Hi,
>>>
>>>Are there any problems or issues when both ISL and 802.1q trunks are
>
> used in
>
>>>the same VTP domain?
>>>
>>>For example, suppose the following:
>>>
>>> ----ISL trunk --------
>>>Sw1 Sw2
>>> ----802.1q trunk----
>>>
>>>Is the above a valid configuration? If so, do any special precautions
>
> need to
>
>>>be taken related to STP or VTP because one trunk is ISL but the other
>
> one is
>
>>>802.1q?
>>>
>>>
>>>Example 2: Assume Sw1 is VTP server and sw2 and sw3 are VTP clients all
>
> in
>
>>>the same VTP domain.
>>>
>>>
>>>Sw1----ISL trunk--------Sw2-------802.1q trunk--------Sw3
>>>
>>>Is this a valid configuration? Any gotcha's I need to be aware of?
>>>
>>>I know that these aren't preferred configs but the Cisco lab is reputed
>
> to
>
>>>test valid config's even if they're not good config's.
>>>
>>>Thanks, dt
>>>
>>>
>>>_______________________________________________________________________
>>>You are subscribed to the GroupStudy.com CCIE R&S Discussion Group.
>>>
>>>Subscription information may be found at:
>>>http://www.groupstudy.com/list/CCIELab.html
>>>
>>
>>--
>>David Madland
>>CCIE# 2016
>>Sr. Network Engineer
>>Qwest Communications
>>612-664-3367
>>
>>"Emotion should reflect reason not guide it"
>>
>
>
>
-- David Madland CCIE# 2016 Sr. Network Engineer Qwest Communications 612-664-3367"Emotion should reflect reason not guide it"
***Get your CCIE and a FREE vacation: Shop.GroupStudy.com***
This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:27 GMT-3