The present application provides a method and an apparatus for avoiding interruptions in an on-going service. A LAN bridge intercepts a trusted port connected to a first routing bridge; determines whether the first routing bridge is forwarding or has a permission to forward data flow from a C-VLAN according to a result of the interception; and if the first routing bridge is not forwarding or no longer has the permission to forward the data flow from the C-VLAN, broadcasts the data flow from the C-VLAN to a second routing bridge so that the second routing bridge forwards the data flow from the C-VLAN. With the method provided in the embodiments of the present application, a forwarding path can be rapidly switched when a designated routing bridge is faulty and cannot carry out a traffic forwarding function or an appointed forwarder of a customer VLAN is changed.