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
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> >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)
> >
>
> ________________________________________________________________________
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>
-----------------------------------------------
Brian Feeny, CCNA, CCDA [EMAIL PROTECTED]
Network Administrator
ShreveNet Inc. (ASN 11881)
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