[c-nsp] What is the lowest latency switch?

[Keegan Holley]

On Thu, Mar 17, 2011 at 3:50 AM, chetan r <chetan.pesit at gmail.com> wrote:

> Why not this?
>
> http://www.cisco.com/en/US/prod/collateral/ps6418/ps6419/ps6421/product_data_sheet0900aecd8029fdf7.html
>


>
> <
> http://www.cisco.com/en/US/prod/collateral/ps6418/ps6419/ps6421/product_data_sheet0900aecd8029fdf7.html
> >The
> data sheet says that it has "<200 nano-second port-to-port latency".
>

You can't really compare infinband to ethernet.  It's kind of comparing a
sports car and a space shuttle.  Infiniband has much higher throughput and
much lower latency in general.


> On Wed, Mar 16, 2011 at 5:42 PM, Soon Lee <leekorean at gmail.com> wrote:
>
> > Hi
> >
> > Lowest latency switch hahaha.
> >
> > according to this document(
> >
> http://www.cisco.com/en/US/prod/switches/ps5718/ps6021/stac_report_cisco_catalyst_4900m_10gige_switch.pdf
> > )
> >
> > Latency of C4900M is 19 microseconds.
> >
> > I'm looking for any other vender switch which is low latency switch.
> >
> > If you guys inform me then I will test it with Smartbit or something like
> > that.
> >
> > And cisco says,
> >
> > Examples of Cisco Low-Latency Layer 2 Switches
> > The Cisco Nexus 5000 Series access-layer switch is an example of a
> > low-latency cut-through single-stage fabric implementation that will meet
> > the requirements of all except ultra-low latency applications. The Cisco
> > Nexus 5000 Series uses VOQs to minimize port contention.
> > Another platform that meets most low-latency application requirements is
> > the Cisco Catalyst® 4900M Switch, a store-and-forward switch that fits in
> > the data center access and distribution layers. The Cisco Catalyst 4900M
> > uses a shared-memory architecture with an ultra-low-latency ASIC design.
> >
> >
> >
> http://www.cisco.com/en/US/prod/collateral/switches/ps9441/ps9670/white_paper_c11-465436.html
> >
> > does it mean C4900M is lower latency switch than Nexus 5000 ?
> >
> >
> > Thanks
> >
> > Soon Lee
> > CCIE# 17724
> >
> > -----Original Message-----
> > From: Peter Rathlev [mailto:peter at rathlev.dk]
> > Sent: Wednesday, March 16, 2011 6:09 PM
> > To: Soon Lee
> > Cc: cisco-nsp at puck.nether.net
> > Subject: Re: [c-nsp] What is the lowest switch?
> >
> > On Wed, 2011-03-16 at 18:02 +0900, Soon Lee wrote:
> > > What is the lowest switch?
> >
> > The one at the bottom of the rack? ;-)
> >
> > > I heard C4900M is low latency switch
> > >
> > > Do you know any other vender?
> > >
> > > Please let me know.
> >
> > I guess the standard Cisco answer to low latency would be the cut-through
> > switching Nexus platform. Nexus 5000 would probably fit the description.
> The
> > 4900 is (AFAIK) store-and-forward and thus has slightly higher forwarding
> > latency.
> >
> > Beware that the latency differences are quite small and most peoply have
> no
> > need to the lower.
> >
> > --
> > Peter
> >
> >
> >
> > _______________________________________________
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>
>
>
>
> --
> Chetan R
> Network Consulting Engineer
> Cisco Systems Inc
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