[c-nsp] Cisco 10G gear

Chris Knipe savage at savage.za.org
Sat Jan 17 03:53:01 EST 2015

On Sat, Jan 17, 2015 at 10:21 AM, Michael Loftis <mloftis at wgops.com> wrote:
> Basically, yes, you need DFC to get your target rates. And it's more about
> pps than bps. CFC in non classic mode is 30Mpps for the whole chassis. If
> you have any classic cards you'll be stuck at half that (because the packet
> headers are larger in this mode), 15Mpps. ... I don't think you can get a
> SUP720 entirely without the PFC...as that's basically the bit that's doing
> all the CFC decision making. The system will be limited in scale and
> features to the lowest common denominator between your DFC(s) and PFC. This
> is all in the FAQ below

I'm still confused :-( Sorry.  The only other line card in the chassis
would be one WS-X6748-GE-TX which is a 48 Port 10/100/1000 card.

Yes, the SUP720 comes with MSFC3/PFC3 standard (we will be upgrading
memory on the SUP as well as the MFC to 1G, the max supported), and it
states it can deliver up to 40Gbps per slot.  But from what you've
mentioned, we will thus now be limited to 15Mpps which is clearly not
going to be enough.

The SUP720-3B is perhaps also an option, but if I have to start
looking at the 720-3BXL then it's becoming very expensive, yet again.
Do I then also understand correctly that in the case of a SUP720-3B I
need to purchase a WS-X6708-10G-3C and in the case of a SUP720-3BXL we
are talking about a WS-X6708-10G-3CXL (there are no 4-port line card
available with a DFC daughter card), or are these special versions
with the daughter cards only required to lower the impact of the
contention on the 8-port cards?

Would the same also hold true then on a SUP720-3B or SUP720-3BXL in
the case of a WS-X6704-10GE, or would the bigger (better) SUP have no
problem with smashing the 15/30Mpps to pieces and deliver true 10Gbps
per port?  I'm not after 100% guaranteed 10Gbps per port on the line
card, but I most certainly don't want to spend all this money and only
get like ~3Gbps per port either.

What other options (except Nexus) would there be that can deliver ~8 x
10GE (fiber) and 48 x 1GE at an affordable rate?  Nexus is WAY over my
budget (and the reason why we're looking at the 6500 instead), and it
would seem (to me at least) I am stuck between a rock and a hard place
in terms of acquiring a low port density 10G switch at an affordable

Sorry for all the questions, in my 15 odd years of networking, this is
the first time that I will be entering the 10GE arena, so I really
want to just make sure that I get the correct kit from the start.
These toys aren't cheap :-(


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