From: John Jones (acer0001@gmail.com)
Date: Fri Feb 09 2007 - 11:29:38 ART
As a follow-up question, since dot1q traunking is used by the customer to
get vlans to the provider, what happens to the native vlan? Is it tagged by
the provider with no customer inside tag and transmitted like all others
tagged vlans?
John
On 2/7/07, Sree N <nsree.ca@gmail.com> wrote:
>
> The CDP and VTP part is not entirely true. Consider using L2 protocol
> tunneling for this purpose. Otherwise even with dot1q tunneling VTP and
> CDP
> frames will be terminated... not tunneled.
>
> On 2/5/07, Alex Ouraev <ualexv@gmail.com> wrote:
> >
> > Think about this from the service provider's perspective. You need to
> > carry
> > customer vlans/cdp/vtp unchanged between sites. How would you do that
> w/o
> > any knowledge as to how your customer does vlans. The answer is to
> > encapsulate it again into your own packet with your own tag at the
> source
> > switch, then carry it over to the destination customer site,
> de-capsulate
> > if
> > you may and spit out unchanged! I don't know who came up with this idea,
> > but
> > it's simple and brilliant to me... :)
> >
> > HTH
> >
> > Alex
> >
> > -----Original Message-----
> > From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> > Mohammad Saeed
> > Sent: Monday, February 05, 2007 1:07 PM
> > To: Cisco certification
> > Subject: dot1q tunnel mode
> >
> > Hi Evereybody,
> >
> > When we configure this on an interface on 3550 switch:
> >
> > switchport trunk encapsulation dot1q
> > switchport mode trunk
> >
> > that interface will tag all the frames coming from respective vlans
> > except the native vlan.
> >
> > But when we create dot1q tunnel and we configure on one interface that
> > is connected to Customer site to provide dot1q tunneling:
> >
> > switchport mode dot1q-tunnel
> > switchport access-vlan 1000
> >
> > Now as this port will be receiving traffic from multiple vlans, will
> > this interface tag all traffic with VLAN ID 1000 (theoratically it
> > shall not as we are not giving switchport trunk encapsulation dot1q)
> > or leave the traffic tagged with its original vlan. I am not clear in
> > what format this interface will receiving the traffic, will that be
> > normal ethernet frame or ethernet frame tagged with vlan id using
> > dot1q encapsulation. If any one can expalin a little bit, I will
> > appreciate that.....
> >
> > To me it looks like, all traffic will already be encapsulated using
> > dot1q and this interface will mark those frames with VLAN ID 1000 and
> > will pass on to other end of dot1q tunnel.....
> >
> > Regards,
> >
> > Mohammad Zahed Saeed
> >
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