From: Larry Letterman (lletterm@cisco.com)
Date: Wed Feb 19 2003 - 21:04:57 GMT-3
I am posting the reply here, because I think it belongs
here..
I am not surprised that your DC people dont want to be
bothered by your
questions, but we run the layer 2 campus lans at Cisco
exactly the way you
described...redundant trunks and STP blocking the redundant
paths....
Next time you see the cisco NSA guy, ask him why he cant
support you as a customer
using the same design his employer uses and sells to the
world....of course it could not be the
issue of politics, since his customer is in DC...
Larry Letterman
Network Engineer
Cisco Systems
----- Original Message -----
From: "jeff gercken" <jeffgercken@hotmail.com>
To: <ccielab@groupstudy.com>
Sent: Wednesday, February 19, 2003 7:40 AM
Subject: OT 6500 Topology question
> I'm hoping someone can help me understand this. I am a
network engineer for
> a gov't facility in Indiana. We have (32) 6509's
connected (Gig E) in hub
> fashion to two 6509 core switches w/ MSFC's (each having
priority of one of
> two hsrp gateways). There are also around 53 vlans
configured and
> statically trunked to various access-layer switches. Our
utilization is
> almost nothing with 'sh traffic' indicating a peak of 5%.
>
> Vlans that are only on 1 access-layer switch are not
trunked between the
> core switches meaning there are no STP blocked lines. The
DHCP server
> assigns the gateways by round-robin.
>
> I wanted to move to a topology using uplinkfast and
balancing by STP
> portvlan priorities. My reasoning was as much for
monitoring as for
> convergence. Right now I have no idea how the traffic is
flowing and trying
> to use a sniffer is about impossible.
>
> I've been overruled by the guys in DC who seem to believe
that a STP blocked
> link is just as bad as a loop. None will explain their
position, just a
> 'because I said so' answer. They also wouldn't let me
increase the core
> capacity using etherchannel. Our Cisco NSA Engineer(no,
not that NSA) was
> down pushing AVID so I took the opportunity to ask. He
took the same
> position as headquarters but really didn't/couldn't
explain why.
>
> Does any of this make sense to anyone? Would you please
help me to
> understand because it seems to sacrifice a lot just so you
can have 2
> gigabit links instead of 1.
>
> I don't mean to clog up the list with this so please reply
directly.
>
> Thanks in advance,
> Jeff
>
>
>
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