[c-nsp] Performance Difference NM-16ESW-1GIG and NME-16ES-1GIG

[Seth Mattinen]

On 9/23/10 2:32 AM, Jeffrey Denton wrote:
> Looking at getting a couple of 3945s.  NM-16ESW-1GIG is being
> recommended by one of my colleagues.  He prefers the easy of use, not
> having to session in to the module.  It's been pointed out that the
> router IOS will have to devote some of it's time to the module and
> perform the switching functions.  We would have to get the 3945 as the
> module is not supported in the 3945E.
> 
> The NME-16ES-1GIG is of course a newer generation.  The module runs
> it's own IOS image.
> 
> PoE is not a requirement.
> 
> Links to the data sheets:
> http://www.cisco.com/en/US/prod/collateral/routers/ps259/product_data_sheet09186a00801aca3e.html
> http://www.cisco.com/en/US/prod/collateral/routers/ps5855/product_data_sheet0900aecd8028d15f.html
> 
> How much does the older module affect the performance of the router
> itself when compared to the newer module?
> 

The two are completely different beasts that exist together, not
necessarily a replacement or upgrade for the other, so you need to pick
the one that meets your requirements the best.

If you get a NM module the ISR sees/manages it. You do L3 routing with
an SVI. L2 stays on the module, not through the router CPU. The
HWIC-4ESW or HWIC-9ESW modules are the same as a NM-16ESW, the
difference is port count. If you're primarily going to be doing a lot of
L2 traffic and little L3, then this variant will suit you fine. Pretend
it's like having a 2690 series switch in module form; you are saving
space and combining management into a single device.

If you get an NME module then you're effectively buying a 3750 that fits
into the router slot. It runs the 3750 IOS image. Treat it like it's an
external switch, not a module. The advantage is space saving, but they
are indeed two distinct devices.

~Seth