when i read that only business customers are affected, not private i suppose that swisscom is routing business customers to (one or more) other lns of sunrise. is the interconnection between sunrise and swisscom broken? if yes: normally traffic is rerouted to some redundant system (in this case probably lausanne). is the backbone to lausanne too small? capacity problems? planning faults?
maybe the right time to call Andi D. to ask for zero-s. peerings? maybe you can get this now at least in Lausanne ;-)
sorry coundn't stand.
Greetings
Nik