I have a Cisco DPC3939B router. I can not figure out how to broadcast a public WIFI that customers can access while also having a private WIFI for employees. Is this possible? The xfinity public broadcast is not helpful because not all of our customers have Comcast accounts.
I don't think the DPC3939B supports separate customer-side WiFi networks; as far as I know, it can only support 2.4GHz and 5GHz private WiFi for the LAN, as well as the xfinitywifi that you mentioned. If you are wanting to enable guest WiFi access beyond what the DPC3939B can do, you will need to use your own wireless router that has this capability.
train_wreck is right on the mark, as usual ! There is another alternative that I know some other business class customers use on this as somewhat of a customer courtesy. Your Comcast Starter internet and above comes with 2 free email addresses. Some customers will use of of these for their primary administration and the other for their customers to log into for free access. If you are willing to entertain this then make absolutely sure that this is ONLY a totally email service permissions only.
Just for some fyi on the xfinitywifi hotspot, any of your customers can login into this using their own none comcast email address credentials. This is done by using the non-comcaster user or guest account, if you will, and this provides two 1 hour free sessions over a 30 days timeframe, more can be found at this link .
Just some food for thought and hope this helps you out.