From: Elias Hill (Elias.Hill@xxxxxxxxxxxxxxxx)
Date: Thu Mar 01 2001 - 15:01:52 GMT-3
New inquiry about 802.1Q:
In regard to dot1q, I was playing around with a Cat6509 and noticed GARP and
GVRP. Looking a little further, it looks like it supplies similar services
as VTP (i.e VLAN configuration exchange between switches). Has anyone
tinkered with this?
-----Original Message-----
From: Russ Meyer [mailto:rmeyer@cisco.com]
Sent: Thursday, March 01, 2001 9:02 AM
To: ccielab@groupstudy.com
Subject: RE: ISL Trunking vs dot1q
Importance: Low
Dot1Q does not encapsulate the native vlan. The Catalyst 4000/2948G won't
run ISL so if you have any of those in your network, you may want to use
dot1q, but you can also mix and match if you had too. For more see:
http://www.cisco.com/warp/customer/473/#Trunking
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Yi Fang
Sent: Thursday, March 01, 2001 11:50
To: Halaska, David; andrew.2.shore@bt.com; lm_nguyen@hotmail.com;
ccielab@groupstudy.com
Subject: Re: ISL Trunking vs dot1q
As far as I remember, it's ISL who does not tag the native vlan. This is the
reason when you setup trunking port, you need to make sure their native vlan
are the same on both ends. Otherwise, your trunking messed up. On the other
hand, dot1q inserts a field into frame header, it doesn't care which vlan it
is. Are I right here?
Yi Fang
----- Original Message -----
From: "Halaska, David" <David.Halaska@getronics.com>
To: <andrew.2.shore@bt.com>; <lm_nguyen@hotmail.com>;
<ccielab@groupstudy.com>
Sent: Thursday, March 01, 2001 9:27 AM
Subject: RE: ISL Trunking vs dot1q
> One drawback to dot1q is that it does not tag the native vlan. Its better
> for your native vlan to be a bogus vlan if using dot1q. ISL encapsulates
> the packet where dot1q actually alters the packets itself and runs a new
CRC
> on the packet. ISL is Cisco proprietary but I think other companies like
> Lucent have tried to implement it. However, some Cisco switch platforms
> were made by companies that Cisco bought, so they only run dot1q.
>
> Hope this helps
> David
>
> -----Original Message-----
> From: andrew.2.shore@bt.com [mailto:andrew.2.shore@bt.com]
> Sent: Thursday, March 01, 2001 8:29 AM
> To: lm_nguyen@hotmail.com; ccielab@groupstudy.com
> Subject: RE: ISL Trunking vs dot1q
>
>
> WS2948G can only support dot1q trunks which is very starange as its a
cisco
> switch !
>
> isl is better if you only have cisco switches. multiply spanning-tree
> instances is the main reason to use it plus its the default :)
>
> Andrew Shore
> BTcd
> Information Systems Engineering
> Internet & Multimedia
>
>
> -----Original Message-----
> From: Blade Of Darkness [mailto:lm_nguyen@hotmail.com]
> Sent: 01 March 2001 14:20
> To: ccielab@groupstudy.com
> Subject: ISL Trunking vs dot1q
>
>
> Group,
>
> Has anyone experience the pros and cons of isl vs dot1q? I am asking
about
> performance-wise and all equipments are ciscos. Why would one chose to
use
> isl instead of dot1q? And can the cisco WS2948G (only G)
> use isl? I only see dot1q supported.
> Thanks.
>
> Blades of Darkness.
>
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