887's don't have fibre ports (called SFP's). Is the ISP providing a fibre to copper converter or a router that does this?
Secondly, how fast is the connection going to be? The 887 is an ISR router which means EVERYTHING runs through the processor. If it's doing firewall duties and NAT I would expect it to max out at about 30Mb/s even though it has 4 x 10/100 ports available, they won't run at anywhere near this unless it's bare bones.
Check out the numbers here:
http://anticisco.ru/pubs/ISR_G2_Perfomance.pdf Opens a new window
