Communication method for operating a track-bound vehicle (3, 103, 203) with a communication network (2, 102, 202), characterized in that securing a communication via the communication network (2, 102, 202) by means of a terminal device (35a-c, 36a-c, 37a-c, 135a-c, 235a-c) connected to the communication network (2, 102, 202) on the
data link layer of the
OSI model, wherein the terminal (35a-c, 36a-c, 37a-c, 135a-c, 235a-c) is provided with
authentication information (AI) for securing the communication of the terminal (35a-c, 36a-c, 37a-c, 135a-c, 235a-c), wherein the terminal (35a-c, 36a-c, 37a-c, 135a-c, 235a-c) authenticates itself (E, J) to an
authentication server (45a-b, 46a-b, 47a-b, 145a-b, 245a-b) which is connected to the communication network (2, 102, 202) by data technology, wherein the track-bound vehicle (3) has a consist network (15, 16, 17) extending over one or more carriages (5, 6, 7) forming a
train (8), the track-bound vehicle (3) has a
train network (11) which extends over the
train, wherein the
authentication server (45a-b, 46a-b, 47a-b) is part of a node device (25a-b, 26a-b, 27a-b)) which forms a transition between the consist network (15, 16, 17) and the train network (11), wherein the track-bound vehicle (103) comprises a plurality of node devices (125a, 125b), each having an
authentication server (145a, 145b), wherein the
authentication server (145a) of a leading node device (125a) is active, another track-bound vehicle (203) comprises a plurality of node devices (225a, 225b), each having an
authentication server (245a, 245b), wherein the authentication
server (245a) of a leading node device (225a) is active, wherein the track-bound vehicle (103) is coupled to the further track-bound vehicle (203) (G), wherein a node device is designated as the leading node device (125a) of the coupled vehicles (103, 203) (H) and wherein the terminals (135a-c, 235a-c) authenticate themselves (J) to the authentication server (145a) of the leading node device (125a) of the coupled vehicles.