[c-nsp] Hardware Question

[Saku Ytti]

On (2012-07-29 09:59 -0400), Joseph Hardeman wrote:

> I have been asked an interesting question, if I put a WS-X6724-SFP line
> card (without the DFC3BXL daughter card) in with a SUP720-3BXL, does it
> slow the SUP720 down to the SFP card limits?  And I am curious if there is
> a command that would show me that it did or didn't do this.

You can see PFC operating mode with 'show plat hard fpc mode'. But CFC
won't affect PFC operating mode. And PFC operating mode won't affect speed
it'll affect loookup features.

CFC means you're using SUP PFC for lookups, DFC means you're using linecard
DFC for lookups.

With CFC your lookup rate is limited by how many packets you can send over
DBUS from linecard to supervisor. DBUS is 62.5MHz @ 32B per cycle. IPv4
lookup is 2 cycles and IPv6/MPLS are 3 cycles.
This means 62.5/2 = 31.25Mpps or 62.5/3 = 20.83Mpps limits for CFC based
system.

Some features require recirculation, which will negatively affect the
lookup rate.

-- 
  ++ytti