Re: OT : What is Best Practice to avoid Spanning Tree Loops

If you don't have access to more recent technologies as mentioned by
Alexander, you could look at building star type topologies using dynamic
signalled (LACP or PAGP) etherchannels which can mitigate needing to break
loops using STP.

If you have to use STP, root placement is important - make it deterministic
don't rely on chance to get an optimal tree - the same with the secondary
root - personally I prefer to make the root one of the more powerful and
central devices (you could tentatively look at influencing where blocking
occurs as well but that might be taking things a bit far). Also consider
utilising tools like mac move notification if your device supports and use
SNMP to monitor the TCN count

Cheers,
Adam

On Thu, Nov 22, 2012 at 8:41 PM, Alexander Lim <cisco.alexand_at_gmail.com>wrote:

> Avoid using STP altogether, use TRILL or FabricPath in DC, use routed
> access in Campus. :)
>
> Regards,
> Alexander Lim
>
> On 21 Nov, 2012, at 6:18 AM, Tony Singh <mothafungla_at_gmail.com> wrote:
>
> > This is just my advice others may differ, but I'd be looking to deploy
> MST and only look a two instances if you want to load balance the vlans
> from access to core switches, any server facing ports put as portfast thus
> any tcn's it will not flush these ports
> >
> > Carefully plan where you place features such as loop guard & udld on
> fibre ports (no bpdu's received on a port which can cause loops)
> >
> > Also bpduguard where you are not expecting to receive any bpdu's and if
> you do then the port will be disabled.
> >
> > Place root guard around the border of your root switch so that another
> switch cannot send it inferior bpdu's
> >
> > Just my 2cents and by the way I haven't seen your diagram
> >
> > --
> > BR
> >
> > Tony
> >
> > Sent from my iPhone on 3
> >
> > On 15 Nov 2012, at 20:03, Akber Ali Mirza <akberali.cisco_at_gmail.com>
> wrote:
> >
> >> Dear Experts,
> >>
> >>
> >> Can somebody please share your valuable inputs on my below query.
> >>
> >> ~ Akber Mirza.
> >>
> >> On Tue, Nov 13, 2012 at 11:41 AM, Akber Ali Mirza
> >> <akberali.cisco_at_gmail.com>wrote:
> >>
> >>> Dear Friends,
> >>>
> >>>
> >>>
> >>> I want to know what is the best design for avoiding spanning tree
> Loops .
> >>>
> >>> I want to brief you about the our network .
> >>>
> >>>
> >>>
> >>> We have core-sw1 and core-sw2 which are running with Layer3 routing
> >>>
> >>> Core-sw1 is running with Vtp Server and core-sw2 is running with VTP
> >>> client mode.
> >>>
> >>> Core-sw 1 is Primary root and core-sw2 is Secondary root.
> >>>
> >>> All the Access-switches are running in VTP Client mode.
> >>>
> >>>
> >>>
> >>> All Access-switches are directly connected to core1 and core2 switches
> as
> >>> we do not have any distribution switches in our network
> >>>
> >>> to connec the Access switches.
> >>>
> >>>
> >>>
> >>> All the Production servers & Baldecentre switches are connected
> direcly
> >>> to the Core-sw1 instead connecting to a Server Farm Switch. as we donot
> >>> have any ServerFarm switch.
> >>>
> >>>
> >>>
> >>> However , We would like to make changes to our network to avoid or
> reduce
> >>> the Laey2 loops effecting the production traffic .
> >>>
> >>>
> >>>
> >>> I want to know what are the new hardware required to have further best
> >>> desing to avoid Layer 2 loops.
> >>>
> >>>
> >>>
> >>> 1) Distribution switches 4900 ( hardware available) -2 what all we
> >>> need to configure.
> >>>
> >>> 2) Server Farm switch with which sup engine -- what all we need to
> >>> configure.
> >>>
> >>> 3) Are we supposed to connect the Blade switches directly to Core-sw1
> >>> incase if we agree to have server farm (6500) switch can we directly
> connect
> >>>
> >>> the Balde centre switches to Server Farm (6500 ) with access port or
> >>> trunk mode .
> >>>
> >>>
> >>>
> >>> 4) Suppose if i want to configure vlan2 & vlan 222 as my serverfarm
> switch
> >>> , I believe we need to have only these Layer 2 vlans and their
> relevant L3
> >>> vlans. When I do this I guess we will not have any impact on the
> servers
> >>> incase if any loop occurs in the access-switches which are connected to
> >>> Distribution switches. Please correct me if i am wrong ?
> >>>
> >>>
> >>>
> >>>
> >>>
> >>> I am attaching the diagram of our existing setup and please recommend
> me
> >>> the best design to avoid L2 loops .
> >>>
> >>>
> >>>
> >>> Appreciate your quick and valuable response.
> >>>
> >>>
> >>> Regards,
> >>>
> >>> Akber Mirza.
> >>
> >>
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Received on Thu Nov 22 2012 - 21:01:23 ART