From: Emad (emad@zakq8.com)
Date: Fri Jul 11 2003 - 17:21:00 GMT-3
No if I put only one vlan allowed on each trunk , when one link fail the
other trunk will not carry the other vlan which is not specified from
the beginning , I think I should define the two vlans under the trunk on
each link , shouldn't I?
-----Original Message-----
From: Larry Letterman [mailto:lletterm@cisco.com]
Sent: Friday, July 11, 2003 11:19 PM
To: 'Emad '; 'Larson, Chris'; boby2kusa@hotmail.com;
ccielab@groupstudy.com
Subject: RE: Switching: OT network design
Each is a trunk and can carry one vlan to the core switch...
One trunk carries vlan a to core 1, one trunk carries vlan b
To core 2..if a trunk link fails , both vlans go up the other
Trunk...
Larry Letterman
Cisco Systems
-----Original Message-----
From: Emad [mailto:emad@zakq8.com]
Sent: Friday, July 11, 2003 1:11 PM
To: 'Larry Letterman'; 'Larson, Chris'; boby2kusa@hotmail.com;
ccielab@groupstudy.com
Subject: RE: Switching: OT network design
Importance: High
will each link carry only one vlan or will be trunk?
-----Original Message-----
From: Larry Letterman [mailto:lletterm@cisco.com]
Sent: Friday, July 11, 2003 11:09 PM
To: 'Emad '; 'Larson, Chris'; boby2kusa@hotmail.com;
ccielab@groupstudy.com
Subject: RE: Switching: OT network design
Each core switch is the root for one vlan and the secondary for the
other.. That takes care of redundancy
Larry Letterman
Cisco Systems
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
Emad
Sent: Friday, July 11, 2003 12:56 PM
To: 'Larson, Chris'; boby2kusa@hotmail.com; ccielab@groupstudy.com
Subject: RE: Switching: OT network design
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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