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

[Phil Mayers]

Marcus.Gerdon wrote:
> Hi Rodney,
> 
> it might be a problem that one customer wants to behave it in one way
> and the next customer in another.
> 
> I tend to think about this a bit different.
> 
> 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."

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


> 
> Reorganization of the TCAM seriously affects traffic forwarding -
> I've already verified that by the various 'cef inconsistency'
> options. So that's no real option to implement.
> 
> Compressing the TCAM entries... that might provide a way to put more
> prefixes into the TCAM.
> 
> But in my opinion that's not really necessary. The TCAM serves
> roughly 250k entries. That's what it is designed and built for. All I
> expect is that fallback to work correctly.

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