MX Series routers ensure network and service availability with a broad set of multilayered physical, logical, and protocol-level resiliency features, Including Juniper?s Virtual Chassis technology, which supports chassis-level redundancy while enabling users to manage two routers as a single element. Additionally, a multichassis link aggregation group (MC-LAG) implementation supports stateful chassis, card, and port redundancy, as well as subscriber and session persistence.