From: ccie2be (ccie2be@nyc.rr.com)
Date: Fri Sep 12 2003 - 13:08:28 GMT-3
Hi Chuck,
Thanks for getting back to me on this.
Your question, "Can the router bridge ISL or dot1q?" is at the heart of this
issue, but I don't know the answer. Switches understand VTP and process VTP
messages and generate VTP frames. I don't think a router does even if it's
bridging fast ethernet interfaces together. But, what does a router do when
a VTP frame comes in on interface configured as a trunk that's bridged to
another interface configured as a trunk? Does it drop the frame even if
it's less than 1518 bytes long? You seem to imply that it does. Or, does
it switch the vtp frame to the other trunk?
Can a router be configured somehow to understand VTP and behave like a
Catalyst when it's bridging trunks?
If it can, then the switches can be in the same VTP domain.
If it can't, but it passes the vtp frames over to other bridged interfaces,
then the switches can still be in the same VTP domain.
If I had the equipment, these questions would be fairly easy test, but,
unfortunately I don't.
Thanks again.
dt
----- Original Message -----
From: "Charles Church" <cchurch@wamnet.com>
To: "ccie2be" <ccie2be@nyc.rr.com>; "Group Study" <ccielab@groupstudy.com>
Sent: Friday, September 12, 2003 9:52 AM
Subject: RE: VTP and bridged interfaces on routers
> Keep in mind that VTP will only travel over trunks, and use VLAN 1 whether
> it's ISL or dot1q. Can the router bridge ISL or dot1q? Keep in mind that
> all ISL and all non-default VLAN dot1q frames will be dropped by the
router
> if it's not expecting frames larger the 1518 bytes.
>
> Chuck Church
> CCIE #8776, MCNE, MCSE
> Wam!Net Government Services
> 13665 Dulles Technology Dr. Ste 250
> Herndon, VA 20171
> Office: 703-480-2569
> Cell: 703-819-3495
> cchurch@wamnet.com
> PGP key: http://pgp.mit.edu:11371/pks/lookup?search=chuck+church&op=index
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
> ccie2be
> Sent: Friday, September 12, 2003 9:07 AM
> To: Group Study
> Subject: Re: VTP and bridged interfaces on routers
>
>
> Hi Daniel,
>
> Thanks for getting back to me. It was the document at that link that made
> me wonder about whether VTP messages could transit bridged interfaces on a
> router. Unfortunately, this document doesn't address that question and I
> wasn't able to find any documents that say anything about this.
>
> I wish I had the equipment to test this.
>
> dt
>
> ----- Original Message -----
> From: "Daniel Sheedy" <dansheedy@gmx.net>
> To: <ccielab@groupstudy.com>
> Cc: "ccie2be" <ccie2be@nyc.rr.com>
> Sent: Friday, September 12, 2003 7:02 AM
> Subject: Re: VTP and bridged interfaces on routers
>
>
> > Hi dt,
> >
> > I found an interesting link here:
> >
> >
>
http://www.cisco.com/en/US/tech/tk389/tk689/technologies_tech_note09186a0080
> 094663.shtml
> >
> > It uses IRB to span a VLAN over a router, and seems to be fairly well
> > explained. I looks like the similar setup to what you are trying to
> > achieve.
> > It even gives the config which is handy. Not too many commands are
> needed,
> > and nothing to tricky.
> >
> > Daniel Sheedy
> >
> >
> > ----- Original Message -----
> > From: "ccie2be" <ccie2be@nyc.rr.com>
> > To: "Group Study" <ccielab@groupstudy.com>
> > Sent: Thursday, September 11, 2003 10:59 PM
> > Subject: VTP and bridged interfaces on routers
> >
> >
> > > Hi all,
> > >
> > > I'm unable to test this so I'm posting this question.
> > >
> > > Assume the following:
> > >
> > > Switch1---trunk------fa0/0 router fa0/1----trunk----Switch2
> > >
> > > On the router the 2 fa interfaces are bridged together.
> > >
> > > Switch1 is a vtp server and Switch2 is a vtp client.
> > >
> > > Question? Will vtp messages get from Switch 1 to Switch 2 without
any
> > > special configuration on the router other than bridging the 2
> fastethernet
> > > interfaces together?
> > >
> > > If some configuration is needed on the router to make this work, what
> > needs to
> > > be done?
> > >
> > > Thanks in advance, dt
> > >
> > >
> > >
This archive was generated by hypermail 2.1.4 : Wed Oct 01 2003 - 07:24:27 GMT-3