Spoke to Xilo last night. INP1 is not available on the Be 16 package that I'm on, it's either INP2 (current setting) or INP0.
With regards to the router, Cisco say this:
Q. Does the Cisco 870 and 850 series support extended INP functions?
A. All the platforms support INP, but only Cisco 877M supports the extended INP functions.
Q. What do I need to know about INP support on the Cisco 870 and 850 series?
A. With Cisco 877 and Cisco 857, customers may experience lower than expected downstream rate when INP is enabled on the DSLAM. This is due to a limitation with the MTK20196 chipset. This issue is addressed with the Cisco 877M platform, using the newer MTK20196P chipset.
Regards,
Stuart
Current ISP: Xilo (via Be LLU)
Previous ISP: Zen (for 9 years).