We had a problem with one of our SS7 national interconections in Zurich.
After the problem was detected all calls were rerouted. However this redirection overloaded all other interconnections which caused quality problems at peak times. Calls to all non-geographic numbers 0800, 0848, etc, were temporarily impossible.
The outage started yesterday 2011-11-14 at 16:00 and was solved today at 11:00. The interconection is now being used again and everything is back to normal.
We apologize to the customers affected.
Best regards
The Switzernet team