From: keith tokash (ktokash@hotmail.com)
Date: Sat Dec 08 2007 - 17:56:01 ART
Our rep has been pushing VSS aggressively, but I'm not sold. It sounds nice,
but our data centers have fully-redundant paths everywhere - from the rack
switches to the distribution (L2) and from the dist to the core (L2). One
half is shut down by STP obviously, but to be honest I like it that way.
Being active/passive as opposed to active/active (as in the case of VSS)
throws a technical barrier between management's tendency to ignore or downplay
the necessity of keeping redundant links under 50% utilization.
If you go active/active and things creep up to 60%, you may not catch it, or
management may not feel like spending the money to upgrade. When something
fails (chassis, sup, line card, optic, someone kicks a fiber jumper walking
past...) you start dropping packets. Depending upon the character of your
management, you may find yourself quickly under a bus. If money is tight, I
would use VSS after making sure everyone and their mothers knew the risks - in
writing (read: very public email thread, very clear wording).
I'm also concerned that junior network engineers won't grasp the subtleties of
port-channeling across multiple chassis, specifically that port-channeling is
all about STP's view of your interfaces. STP has a reputation, IMO, as one of
the most underestimated core technologies, and one that requires multiple
revisits. People tend to "get it", then a month later have no idea how a
failure scenario will play out.
So I suppose my concerns are more about politics and opex than the technology,
which I think is pretty cool.
With a few exceptions, secrecy is deeply incompatible with democracy and with
science.
--Carl Sagan
> Subject: RE: qs - 6500 VS
> Date: Thu, 6 Dec 2007 09:55:30 -0500
> From: mikraus@cisco.com
> To: pahujat@gmail.com; l3type@gmail.com
> CC: ccielab@groupstudy.com
>
> Be cautious with service modules, most all service modules are not yet
> supported within VSS today. So, if you need service module support, I'd
> talk to your Cisco SE to understand the timelines of when support will
> be available for the service module in question.
>
> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
> Tarun Pahuja
> Sent: Thursday, December 06, 2007 8:24 AM
> To: l3type
> Cc: ccielab@groupstudy.com
> Subject: Re: qs - 6500 VS
>
> VSS is a Win Win solution if you have the money for it.
>
> http://www.cisco.com/application/pdf/en/us/guest/products/ps9336/c2134/c
> dccont_0900aecd806ee2d4.pdf
>
> "VSS increases operational efficiency
>
> 1) Single point of management including configuration
> 2) Single gateway IP address (eliminates Hot Standby Router Protocol
> (HSRP)/ Virtual Router Redundancy Protocol (VRRP)/ Gateway Load
> Balancing Protocol
> (GLBP))
>
> 3) Multi-chassis EtherChannel(R) (MEC) creates simplified loop-free
> topologies, eliminating the dependency on Spanning Tree Protocol (STP)
>
> 4) Flexible deployment options in terms of location of the underlying
> physical switches as they are connected via standard 10 Gigabit Ethernet
> interfaces."
>
> HTH,
> Tarun
>
>
> On 12/6/07, l3type <l3type@gmail.com> wrote:
> >
> > Guys, I know this is a switching question but wanted to get the
> > opinion of esteemed experts on this board
> >
> >
> >
> > I want to know when should I recommend the 6500 VSS and when to
> > recommend the plain 6500's? If there are only advantages to going with
>
> > VSS, why would anybody recommend the separate 6500's at the core
> > solution?
> >
> >
> >
> > Also, is there a risk going with a new product like the VSS or does
> > Cisco have some documented case studies with customers already running
> it?
> >
> >
> >
> >
> >
> > Or would the best thing to do is to recommend a client to buy
> > VSS-capable parts at the moment but run the switches in standalone
> > mode which is supposed by Cisco
> >
> >
> >
> > Thanks all
> >
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