[c-nsp] Nexus 2000 vs Catalyst 4948 for access layer

[Livio Zanol Puppim]

Yeah, You are right.

But I would like to use my nexus 5000 10GE/FCoE ports just for access
servers, maximizing it's use... The uplinks from Nexus 2000 could easially
go directly to my distribution/core. Unfortunally, nexus 2000 is just an
fabric extender and can ONLY be attached to Nexus 5000... Maybe CISCO
changes it's later...

Let's think:

10 nexus 2000 using all uplink ports = 40 ports. Yes, 40 ports that I must
use at my nexus 5000. That's more than 1 entirelly switch (1RU) and almost 1
switch (2RU).

I haven't figure out yet what's the advantage of having this design (nexus
2000 -> nexus 5000) other than the "old" one (catalyst 4948 -> nexus
7000/cisco 6500). That's what I'm talking about.

The only REAL advantage so far is the vPC...

2010/2/2 Brad Hedlund <brhedlun at cisco.com>

>
> True, the Nexus 2000 does not locally switch, but lets explore that for a
> second...
>
> 1) a typical enterprise Data Center is running applications that are not
> latency sensitive, where latencies in the 10s of microseconds are perfectly
> OK and nobody is really counting anyway. Only in the small minority of Data
> Centers running high frequency trading, grid computing, or some other ultra
> low latency application, every *nanosecond* matters and local switching with
> fewer hops is of paramount importance. Furthermore, these applications are
> quickly migrating away from 1GE to 10GE attached servers for the obvious low
> latency advantages.
>
> 2) the Nexus 2000 has 4x10GE uplink bandwidth versus the 2x10GE uplink for
> 4948.  This results in a possible 1:1.2 oversubscription ratio for Nexus
> 2000 to handle the additional uplink load that may otherwise not be present
> on a 4948.
>
> 3) The upstream Nexus 5000 implements cut-through switching, and the Nexus
> 2000 itself also uses cut-through for frames entering on 1GE and egressing
> on 10GE.  The two combined often results in port-to-port latencies similar
> to a Catalyst 6500, even without the "local switching".  If you are
> comfortable with your Catalyst 6500 local switching latencies, you can
> expect similar performance from a Nexus 2000/5000 combination.
>
>
> --
> Brad Hedlund, CCIE #5530
> Consulting Systems Engineer, Data Center
> bhedlund at cisco.com
> http://www.internetworkexpert.org
>
>
>
> On Jan 31, 2010, at 5:25 PM, David Hughes wrote:
>
> >
> > On 29/01/2010, at 6:54 AM, Livio Zanol Puppim wrote:
> >
> >> Can anyone please tell me the advantages of using Nexus 2000 over
> Catalyst
> >> 4948 as access layers switches?
> >> Using Nexus 2000, I have to use at least 2 ports at my Nexus 5000, that
> >> could be used by servers with 10GbE/FCoE servers.
> >
> > The N2K does no local switching so if you have any east-west traffic
> between ports on the same switch you'll be better served by a more
> "traditional" access switch.  Naturally the N2K offers centralised
> management etc etc but that may or may not be of interest depending on the
> size of your deployment.
> >
> >
> >
> > David
> > ...
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>
>


-- 
[]'s

Lívio Zanol Puppim