From: Larry Letterman (lletterm@cisco.com)
Date: Fri Jul 11 2003 - 17:35:30 GMT-3
Its easier than that..
Make core-1 root primary for vlan X
Make core-1 root secondary for vlan Y
Do the opposite on core-2
Larry Letterman
Cisco Systems
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
boby2kusa@hotmail.com
Sent: Friday, July 11, 2003 1:30 PM
To: Larson, Chris; 'Emad '; ccielab@groupstudy.com
Subject: Re: Switching: OT network design
for example,
6509 ----isl/dot1q----4506
| |
| isl/dot1q
|-------isl/dot1q-----4506
Before anyone say that Cat4K does not support ISL, I am assuming that
the sup is Sup3 or Sup4 which both support ISL and dot1q
The 6509 is the root only one of this port going to 4506 will be
forwarding for both vlans, so in order to achive load balancing you have
to make one port going to one 4506 forwarding for that vlan and blockign
for the other vlan. The same should be done for the other trunk but the
opposite vlan. I believe you can accomplish by changing the root port
cost or root port priority for each vlan.
I do not think pruning a vlan on a trunk would make it forward that vlan
if the other link goes down since it's being pruned.
----- Original Message -----
From: "Larson, Chris" <CLarson@usaid.gov>
To: "'Emad '" <emad@zakq8.com>; "Larson, Chris" <CLarson@usaid.gov>;
<boby2kusa@hotmail.com>; <ccielab@groupstudy.com>
Sent: Friday, July 11, 2003 1:21 PM
Subject: RE: Switching: OT network design
> Yes both uplinks will be trunked, but one of the vlans will be
> blocked.
ie.
> on the uplink to core 1 even would be blocked, but it coudl carry both
> 1
and
> 2 (failure of core 2). So they will all be trunked.
>
> > -----Original Message-----
> > From: Emad [SMTP:emad@zakq8.com]
> > Sent: Friday, July 11, 2003 3:56 PM
> > To: 'Larson, Chris'; boby2kusa@hotmail.com; ccielab@groupstudy.com
> > Subject: RE: Switching: OT network design
> > Importance: High
> >
> > Larson
> > U are right in this point and I already know it , but I don't know
> > how we will treat the two uplinks of the 4000 switch to the two core
> > switches , will each link carry only one vlan or will be trunk?
> > Because I need redundancy also , if one link or one core switch
> > failed , I need the another link to carry the traffic of both vlans
> > to the another core switch
> >
> > Regards
> >
> > -----Original Message-----
> > From: Larson, Chris [mailto:CLarson@usaid.gov]
> > Sent: Friday, July 11, 2003 10:41 PM
> > To: 'boby2kusa@hotmail.com'; Emad; ccielab@groupstudy.com
> > Subject: RE: Switching: OT network design
> >
> > If each access layer switch has 2 vlans and a 1 gig uplink to 2 core
> > switches then the simplest thing to do is to make 1 core switch root
> > for 1 of the vlans on each access layer switch and the other core
> > root for the other vlan on each access-layer switch. Etherchannel is
> > not appropriate because etherchannel can only be done to a single
> > switch.
> >
> > In the Cisco switching guides they use even and odd vlans as an
> > example. So for instance if each access switch has consecutive vlans
> > ie. AccessSwitch1
> > = Vlan1, Vlan2 AccessSwitch2 = Vlan2, Vlan 3
> >
> > Then the config on core 1 is along the lines of
> >
> > set spanning root vlan 1,3,5,7,9
> > set spanning root vlan 2,4,6,8 secondary
> >
> > And on Core 2
> >
> > set spanning root vlan 2,4,6,8
> > set spanning root vlan 1,3,5,7,9
> >
> >
> >
> > Then you will "load balance" across both uplinks from each closet
> > switch to the core.
> >
> >
> >
> >
> >
> >
> >
> > > -----Original Message-----
> > > From: boby2kusa@hotmail.com [SMTP:boby2kusa@hotmail.com]
> > > Sent: Friday, July 11, 2003 3:22 PM
> > > To: Emad ; ccielab@groupstudy.com
> > > Subject: Re: Switching: OT network design
> > >
> > > ----- Original Message -----
> > > From: "Emad " <emad@zakq8.com>
> > > To: <ccielab@groupstudy.com>
> > > Sent: Friday, July 11, 2003 11:49 AM
> > > Subject: Switching: OT network design
> > >
> > >
> > > > Folks,
> > > >
> > > > I just wanna share an idea with you all ,
> > > >
> > > > I have 4506 switch in a network acting as the access layer and
> > connected
> > > > to two 6513 core switches with 2G uplink per each one,
> > > >
> > > > Each 4506 switch has 2 vlans and I want to have both uplinks to
> > > > the
> > core
> > > > switches working in load balance , how can we guarantee that:
> > > >
> > > > - By STP layer2 load balance? If yes , plz tell me how?
> > > Do you mean load balance the traffic thoughput between the 2 gig
> > uplinks
> > > or
> > > load balance the switches load?
> > > Load balancing between the 2 gig link can be accomplished by
> > channeling
> > > the
> > > uplinks. Load balancing the the switch's load (for a lack of a
> > > better
> > > term)
> > > can be accomplished by having the one or the other as the bridge
to
> > the
> > > root
> > > (which should be the 6509). For example, 2 vlans, vlan 1 will be
> > > forwarding on 4506 A while blocking the vlan 2 and vice versa for
> > > the other
> > switch.
> > > This would be manipulating either the RP cost or the RP priority,
> > somebody
> > > will correct me if this is the wrong way to manipulate which
> > > switch
> > should
> > > the vlan take on it's way to the root.
> > >
> > > > - By enabling routing protocol between the access layer and the
> > > > core layer , but how?
> > > This would be load balancing on layer 3 and you would load balance
> > > according to the destination of the traffic, routers look at the
> > > routing table
> > to
> > > forward the packet.
> > >
> > > >
> > > > I read the good paper of CISCO AVVID network infrastructure but
> > > > I
> > didn't
> > > > get it because most of scenarios are depending on one vlan and
> > > > redundancy between the two uplinks not load balancing and 2
> > > > vlans,
> > > >
> > > > Plz advice
> > > >
> > > > Thanx
> > > >
> > > >
> > > >
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