There is no UDP port number assigned for GRE because it does not run over UDP. It runs DIRECTLY over IP. Check the RFC if you don’t believe me.
Dino > On Feb 28, 2022, at 9:29 PM, to...@strayalpha.com wrote: > > >>> On Feb 28, 2022, at 8:00 PM, Dino Farinacci <farina...@gmail.com> wrote: >>> >>> There is a base case to the recursion, i.e., where logical information >>> meets fermions and bosons (literally). But that tells you only that base >>> layer; it tells you nothing about the meaning of the headers you see >>> inside, e.g., in OSI, they would be 1,2,3,4,5,6,7, but in an IP tunnel, >>> they could be 1,2,3,3,4,5,6,7, with GRE they could be 1,2,3,2,3,4,5,6,7, >>> etc. >> >> An IP tunnel with protocol number 4 is indeed 1,2,3,3,4,5,6,7, but LISP (UDP >> port 4341) UDP tunnels are 1,2,3,4,3,4,5,6,7 and GRE is 1,2,3,3,4,5,6,7 >> because it runs directly over IP with protocol number 47. >> >> Dino > > If GRE runs over IP, then it would be the same as IP-over-UDP tunnels: > > 1,2,3(IP), 4(GRE, since it is a protocol number of IP), 3(IP in GRE), 5,6,7, > i.e.: 1,2,3,4,3,4,5,6,7 > > It’s all actually relative, though - to the left IP, GRE is layer 4. To the > right IP, GRE is layer 2. > > Joe _______________________________________________ Int-area mailing list Int-area@ietf.org https://www.ietf.org/mailman/listinfo/int-area
