[c-nsp] Hardware limitations on SUP32 with LDP and full routing table

[Jon Lewis]

On Fri, 23 Jan 2009, Phil Mayers wrote:

>> If RIB and FIB differ and by that forwarding isn't done along the
>> paths the protocols selected it is a bug. Either there's a
>> 'fail-over' mode into software when TCAM is full - which is what
>> documentation and error message say - or there isn't.
>
> I can't speak for the 6500 BU, but they've told me in the past:
>
> "If it isn't supported in hardware, it's not supported."

"supported" and "intended to work" can be two different things.

> I suspect the software forwarding path is simply not supported on a 6500.

I think it's "supposed to work" at least for IPv4, but my understanding 
has been that on any platform, MPLS/tag-switching absolutely requires CEF, 
which on the 6500 I suspect means hardware forwarding.

> I do not think your expectations match the intent of the 6500 BU, based on 
> what I've been told in the past.

As has been said before...it's unfortunate cisco decided not to do a 
Sup32-3bxl.  It renders the Sup32 unsuitable for use in networks where a 
Sup2 doesn't cut it, but Sup720-3bxl is overkill.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
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