[c-nsp] SXI4a or SXI5

[Randy McAnally]

> If you were coming from SXF train and doing only a few basic tasks:
> 
> * Full BGP tables from several upstreams
> * Several hundred SVI's (with counters)
> * Basic netflow
> 
> 1. Which would you prefer and why?
> 
> 2. Any gotcha's when going from SXF -> SXI?
> 
> Thanks in advance!

For the record, the upgrade from SXF to SXI5 was smooth and painless. 
Upgraded standby, failed over, reboot primary, back to SSO.

It also resolved some ipv6 specific issues and reduced nominal CPU usage from
10% to 5%.

-Randy