On Thu, 27 Jul 2000 [EMAIL PROTECTED] wrote:
>
> Since we seen to be doing the Spanning Tree simulations today... Imagine
> what happens when you have two instances of STP running, one per VLAN on
> VLAN 100 and VLAN 200, and then hook both VLAN 100 and VLAN 200 to the same
> hub. :-)
if you just had it like this:
/---------Hub----------\
| |
| |
vlan 100 vlan 200
then I don't think it would be too bad since I don't see where a storm
could happen. But if you had like this:
/---------Hub----------\
| |
| |
vlan 100 vlan 200
| |
| |
\----switch/hub--------/
then that would be pretty evil
>
> Have fun! <evil grin>
>
> Karen E Young
> Network Engineer
> ELF Technologies, Inc
> [EMAIL PROTECTED]
>
>
>
>
>
>
> Brian
>
> <signal@shrev To: Marc Quibell <[EMAIL PROTECTED]>
>
> e.net> cc: [EMAIL PROTECTED]
>
> Sent by: Subject: Re: Connecting Switches,
>hubs..
> nobody@groups
>
> tudy.com
>
>
>
>
>
> 07/27/00
>
> 07:40 AM
>
> Please
>
> respond to
>
> Brian
>
>
>
>
>
>
>
>
> On Thu, 27 Jul 2000, Marc Quibell wrote:
>
> > STP does not work with hubs. It only works in a completly switched
> network.
> > Hubs do not run STP, hence the switch does not get BDPU's from the hub
> and
> > does not recognize the non-STP connected ports in order to put the port
> into
> > to a mode such as blocking mode.
>
> correct.
>
> >
> > That said, let's say you do have 2 switch ports (1&2) connected to a same
>
> > hub. A broadcast occurs, which comes in on ports 1&2, but since a
> switched
> > port does not return traffic to the source port, the broadcasts coming in
> on
> > ports 1&2 will not get re-broadcasted back onto themselves...
> >
>
> but broadcasts going out port 1 will still goto port 2 (which isn't
> itself), and vice versa. With no STP, this would create looping.
>
> Brian
>
>
> >
> > >From: Brian <[EMAIL PROTECTED]>
> > >To: Marc Quibell <[EMAIL PROTECTED]>
> > >CC: [EMAIL PROTECTED]
> > >Subject: Re: Connecting Switches, hubs..
> > >Date: Wed, 26 Jul 2000 20:16:32 -0500 (CDT)
> > >MIME-Version: 1.0
> > >Received: from [208.206.76.23] by hotmail.com (3.2) with ESMTP id
> > >MHotMailBB48D86F008DD820F3DAD0CE4C17101E0; Wed Jul 26 18:16:32 2000
> > >Received: from mercury.shreve.net (IDENT:[EMAIL PROTECTED]
> > >[208.206.76.23])by mercury.shreve.net (8.9.3/8.9.3) with ESMTP id
> > >UAA13766;Wed, 26 Jul 2000 20:16:32 -0500
> > >From [EMAIL PROTECTED] Wed Jul 26 18:21:17 2000
> > >In-Reply-To: <[EMAIL PROTECTED]>
> > >Message-ID:
> <[EMAIL PROTECTED]>
> > >
> > >On Wed, 26 Jul 2000, Marc Quibell wrote:
> > >
> > > > Actaully, I did another test in the lab and the STP has nothing to do
>
> > >with
> > > > hubs, so BOTH switch ports were able to plug into both hub ports, no
> > > > problem. Now my next question is: Do I now have an aggregate
> bandwidth
> > >of
> > > > 20mbs?
> > >
> > >Actually STP is important in your example.
> > >
> > >if you have a switch with two ports connected to a hub, say ports 1 and
> > >5. A broadcast sent to port 5, will come back into the switch on port
> > >1. Since switches forward broadcasts, it will go back out port 5, and
> > >back in port 1, and this will continue infinitly if STP is not enabled.
> > >
> > >In multilayer switching networks, you can actually have your broadcasts
> > >magnified, and things can get REAL ugly.
> > >
> > >Brian
> > >
> > >
> > >
> > > >
> > > > TIA!
> > > >
> > > > Marc
> > > >
> > > >
> > > > >From: Brian <[EMAIL PROTECTED]>
> > > > >To: Marc Quibell <[EMAIL PROTECTED]>
> > > > >CC: [EMAIL PROTECTED]
> > > > >Subject: Re: Connecting Switches, hubs..
> > > > >Date: Wed, 26 Jul 2000 12:11:21 -0500 (CDT)
> > > > >MIME-Version: 1.0
> > > > >Received: from [208.206.76.23] by hotmail.com (3.2) with ESMTP id
> > > > >MHotMailBB4866B7003DD82197E9D0CE4C1712E90; Wed Jul 26 10:11:20 2000
> > > > >Received: from mercury.shreve.net (IDENT:[EMAIL PROTECTED]
> > > > >[208.206.76.23])by mercury.shreve.net (8.9.3/8.9.3) with ESMTP id
> > > > >MAA04159;Wed, 26 Jul 2000 12:11:22 -0500
> > > > >From [EMAIL PROTECTED] Wed Jul 26 10:13:33 2000
> > > > >Newsgroups: groupstudy.cisco
> > > > >In-Reply-To: <8lmv6b$do7$[EMAIL PROTECTED]>
> > > > >Message-ID:
> > ><[EMAIL PROTECTED]>
> > > > >References: <8lmv6b$do7$[EMAIL PROTECTED]>
> > > > >
> > > > >On Wed, 26 Jul 2000, Marc Quibell wrote:
> > > > >
> > > > > > I have a simple question, and one which I cannot readily answer
> at
> > >this
> > > > > > time. Can I safely connect TWO switch ports from a Cisco 5509
> (two
> > > > >different
> > > > > > switch blades) to a hub to increase the hub's crossconnection
> > >bandwidth,
> > > > > > without having a looping problem? The hub is actually a DEC
> > >multi-blade,
> > > > > > with a swithced backplane. The hub is also connect on two
> different
> > > > >blades,
> > > > > > but the same backplane. TIA!
> > > > > >
> > > > > > btw, I have already done this and I figured if spanning tree
> found a
> > > > >looping
> > > > > > problem, it wouldv'e set one of the ports to a non-forwarding
> > >state..
> > > > >
> > > > >Correct, so long as you have STP enabled you are ok.
> > > > >
> > > > >Brian
> > > > >
> > > > >
> > > > > >
> > > > > >
> > > > > > ___________________________________
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> > > > >
> > > > >--
> > > > >-----------------------------------------------
> > > > >Brian Feeny, CCNA, CCDA [EMAIL PROTECTED]
> > > > >Network Administrator
> > > > >ShreveNet Inc. (ASN 11881)
> > > > >
> > > >
> > > >
> ________________________________________________________________________
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> > > >
> > >
> > >--
> > >-----------------------------------------------
> > >Brian Feeny, CCNA, CCDA [EMAIL PROTECTED]
> > >Network Administrator
> > >ShreveNet Inc. (ASN 11881)
> > >
> >
> > ________________________________________________________________________
> > Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com
> >
>
> -----------------------------------------------
> Brian Feeny, CCNA, CCDA [EMAIL PROTECTED]
> Network Administrator
> ShreveNet Inc. (ASN 11881)
>
> ___________________________________
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-----------------------------------------------
Brian Feeny, CCNA, CCDA [EMAIL PROTECTED]
Network Administrator
ShreveNet Inc. (ASN 11881)
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