According to an example, a method for avoiding a loop in a network, which is performed by each ED in each VPN site, comprises: interacting with other EDs in a same VPN site to elect a DED; assigning an authorized forwarding instance to each ED in the same VPN site when the ED is elected as the DED; obtaining the authorized forwarding instance from the DED when the ED is not elected as the DED; allowing traffic of the authorized forwarding instance transmitted from or to a public network, and blocking traffic of unauthorized forwarding instance transmitted from or to the public network.