Multiservice Switch (MSS) is originally a Nortel line of routers, historically called Passport, designed for carrier core and edge routing. They run the Passport Carrier Release operating system. The MSS has a significant installed base, with over 40,000 switches sold. As of 27 September 2010, this product line was sold to Ericsson. The Nortel MSS products have been rebranded to Ericsson PPX.