Method for determining, by means of a router, called initiating router, a route between same and a destination router of a communication network by powerline communication, said method comprising the following steps: - a step E1 of said initiating router broadcasting in said network at least one route request message (RREQ), said destination router responding to said or to each route request message (RREQ) by point-to-point transmission to the initiating router of at least one response message (RREP) identifying a route between said initiating router and said destination router, each response message (RREP) comprising a sequence number assigned sequentially by said destination router, and each route being associated with a period of validity, and, - a step E2 of receiving a response message, called current response message (RREPc), characterized in that it further comprises - a step E3 of attaching a time limit to a response message (RREPc) following a request message (RREQ) for a route to said destination router (Rn) implemented on receipt of said response message (RREPc), the duration of the time limit T0 being substantially of the same magnitude as the estimated maximum time taken by a request message RREQ to pass, through said communication network, from one router to another router of said network, - a step E4 of verifying that upon receipt of a current response message (RREPc), the time limit attached to a response message (RREP-) following a request message (RREQ) for a route to said destination router received previously has not expired, - a step E5 of retaining, as a route between said initiating router and said destination router, the route identified by the response message (RREPc or RREP-) most recently transmitted by said destination router if the time limit attached to said response received previously has not expired, the most recently transmitted response message (RREPc or RREP-) being identified as being the response message including the largest sequence number, and, - a step E6 of retaining the route identified by the current response message (RREPc) even though a response message to a request for a route to said destination router was received previously after the time limit attached to said previously received response had expired. - a step E1 of said initiating router broadcasting in said network at least one route request message (RREQ), said destination router responding to said or to each route request message (RREQ) by point-to-point transmission to the initiating router of at least one response message (RREP) identifying a route between said initiating router and said destination router, each response message (RREP) comprising a sequence number assigned sequentially by said destination router, and each route being associated with a period of validity, and, - a step E2 of receiving a response message, called current response message (RREPc), - a step E3 of attaching a time limit to a response message (RREPc) following a request message (RREQ) for a route to said destination router (Rn) implemented on receipt of said response message (RREPc), the duration of the time limit T0 being substantially of the same magnitude as the estimated maximum time taken by a request message RREQ to pass, through said communication network, from one router to another router of said network, - a step E4 of verifying that upon receipt of a current response message (RREPc), the time limit attached to a response message (RREP-) following a request message (RREQ) for a route to said destination router received previously has not expired, - a step E5 of retaining, as a route between said initiating router and said destination router, the route identified by the response message (RREPc or RREP-) most recently transmitted by said destination router if the time limit attached to said response received previously has not expired, the most recently transmitted response message (RREPc or RREP-) being identified as being the response message including the largest sequence number, and, - a step E6 of retaining the route identified by the current response message (RREPc) even though a response message to a request for a route to said destination router was received previously after the time limit attached to said previously received response had expired.