Re: [Int-area] tunneling and recursion (was: Re: New Version Notification for draft-li-int-aggregation-00.txt)

[Dino Farinacci <[e-mail]>]

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, [e-mail] wrote:
> 
> 
>>> On Feb 28, 2022, at 8:00 PM, Dino Farinacci <[e-mail]> 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