The present invention discloses a method, routing bridge, and system for sending a packet, which are applied to the field of communications technologies, and are invented to reduce a signaling overhead of a TRILL network. The method includes: receiving, by a first transit RB, a Nickname of an edge RB sent by a second transit RB; constructing, an address advertisement message, where the address advertisement message includes a virtual IP address and a virtual MAC address of the first transit RB; and sending, the address advertisement message to the edge RB according to the Nickname of the edge RB, so that the edge RB sends, after receiving the address advertisement message, a free ARP packet to a server that accesses the TRILL network through the edge RB, where the free ARP packet includes a correspondence between the virtual MAC address and the virtual IP address.