From San Francisco to Atlanta to Fairfax. http://www.newsweek.com/comcast-xfinity-down-outage-not-working-internet-my-area-1002278.
Of course the links don't work when your Internet is down.
One of Comcast’s large backbone network partners had a fiber cut that we believe is also impacting other providers. It is currently affecting our business and residential internet, video and voice customers. We apologize & are working to get services restored as soon as possible