iRadio buffering with Time Capsule and NDS

My domestic internet is supplied via 16mb/sec fibre service and feeds into a Time Capsule.  However, on high def radio channels the service gets interrupted due to buffering issues.  This is easily seen with the buffering display switched on the NDS.

I had heard that maybe there is a setting issue with the Time Capsule, but I cannot see any modifications I can make to the Time Capsule set up.

Can anybody help please?

Thanks

David