Layer 2 vs. Layer 3 to TOR

Brandon Galbraith brandon.galbraith at gmail.com
Thu Nov 12 14:49:37 CST 2009


On Thu, Nov 12, 2009 at 2:40 PM, Bulger, Tim <Tim_Bulger at polk.com> wrote:

> If you use stackable switches, you can stack across cabinets (up to 3 with
> 1 meter Cisco 3750 Stackwise), and uplink on the ends.  It's a pretty solid
> layout if you plan your port needs properly based on NIC density and cabinet
> size, plus you can cable cleanly to an adjacent cabinet's switch if
> necessary.
>
> Slightly off-topic.. Consider offloading 100Mb connections like PDUs,
> DRAC/iLO, etc. to lower cost switches to get the most out of your premium
> ports.
>

Agreed. We use Netgear gigabit unmanaged switches for what Tim suggests to
save the higher-cost-per-port switchports for server gear.

-brandon



> -Tim
>
> -----Original Message-----
> From: Seth Mattinen [mailto:sethm at rollernet.us]
> Sent: Thursday, November 12, 2009 3:20 PM
> To: 'nanog at nanog.org'
> Subject: Re: Layer 2 vs. Layer 3 to TOR
>
> Steve Feldman wrote:
> >
> > On Nov 12, 2009, at 2:48 PM, Raj Singh wrote:
> >
> >> Guys,
> >>
> >> I am wondering how many of you are doing layer 3 to top of rack
> >> switches and what the pros and cons are. Also, if you are doing layer
> >> 3 to top of  rack do you guys have any links to published white papers
> >> on it?
> >
> > Dani Roisman gave an excellent talk on this subject at NANOG 46 in
> > Philadelpha:
> >
> >
> >
> http://www.nanog.org/meetings/nanog46/abstracts.php?pt=MTQwOCZuYW5vZzQ2&nm=nanog46
> >
>
>
> I'd always wondered how you make a subnet available across racks with L3
> rack switching. It seems that you don't.
>
> ~Seth
>
>


-- 
Brandon Galbraith
Mobile: 630.400.6992
FNAL: 630.840.2141



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