Alexa/Sonos noob here. Just posting this in case it can help anyone else. I was experiencing really slow response time from Alexa for simple questions, over 15 seconds. My internet connection was reasonably fast at 6 Mbps so I was confused. But it turned out it only supported 256 Kbps for upload! Alexa needs to send outbound messages so that is a potential bottleneck, although even that low bandwidth will usually give acceptable response time. But at this particular time I was also uploading a number of files from my PC so the traffic completely bogged down. Once I paused the uploads Alexa response time returned to normal. So remember that upload speeds matter and so does other network traffic.