Cisco Scientific Atlanta DPC2100/EPC2100: What ports need to be open and how?

Cisco (Modems/Gateways) Scientific Atlanta DPC2100/EPC2100 (Modem): What ports need to be open and how?
I'm guessing it's that since it looks like the one I'm using.

I just upgraded to a new modem and my xbox one is fixed perfectly where I have a high upload and dowload but my 360 is disconnecting over and over and I don't know where to go or what to do or how to do it. I can enter my modem settings but Idk where to
go for ports and open them or anything like that (I DON'T HAVE A PC TO DO THIS I USE MY PHONE AND IT'S POSSIBLE TO USE A PHONE SINCE MY FRIEND DID IT BUT HE'S BEEN GONE) so I need some help thanks.

:)

 

My XBOX 360 does not process the update

Ok I followed step by step but I still cannot update my XBOX

MY router model Is : NETGEAR WNR1000 And my modem is: Scientific Atlanta DPC2100 SERIES "Webstar"

 

RoadRunner: Overview

RoadRunner (ISPs): Overview
Internet service type: Cable



Common devices:

Motorola: SBV5222

Scientific Atlanta: DPC2100

Ubee: U10C018,U10C022



ISP Website: Internet, Cable TV, and Phone Service | Spectrum



Support number: 1-866-744-1678



Merged with: Time Warner, Brighthouse