[c-nsp] Cat6500 with SUP720-3B or SUP720-3BXL memory question?

[Gary Buhrmaster]

On Thu, Jun 9, 2011 at 19:19, Howard Leadmon <howard at leadmon.net> wrote:
....
> Now maybe I am reading this wrong, but it sounds like upgrading the RP and SP
> RAM to 1G on the 3B will effectively make it a 3BXL, is this correct?

The upgrade kit includes two parts, the RAM, and a replacement
PFC module, which includes TCAM with more memory lines
enabled(*).  The RAM provides more space for BGP tables, and
the TCAM for the actual hardware forwarding table.  You need
both to get to the larger table sizes with hardware forwarding.

It was my recollection that more recent shipping 720's already
have 1GB of RAM, but some of the older ones do not, so it
is included in the upgrade kit (even if you do not need it).

Gary

(*) The early PFCs were clearly different, and presumable
    were differently manufactured.  It was (for the time) a
    rather large chip, and yields probably varied.  The more
    recent Bs and BXLs seem to look suspiciously similiar,
    and while some binning may occur (just like Intel CPU)
    for partial operation, I also suspect that with a die
    shrink and todays newer fabs that some BXL parts
    simply have some perfectly good TCAM disabled and
    sold as B.  This is conjecture.  Do not take this as
    anything more than conjecture.  But it would be
    consistent with common practice.