[c-nsp] 7507s: which image for production? For IPv6?

[Buhrmaster, Gary]

> which image train is most stable?

The 7500's make Swiss army knives feel inadequate. 
There are just too many possibilities of hardware
and feature combinations to say anything absolutely.

That said, my recollection is that Rodney has
been pretty consistent about suggesting 12.0S or
12.4 (mainline) depending on the exact features
you need.  Avoid 12.2S.  Since you want IPv6,
that would mean you would be looking at 12.4.
I am not sure a 256MB RSP4 will fit full BGP
table(s) (although others may have experience).

(Apologies to Rodney if I have mischaracterized
his recommendations).