[SOLVED] What RFC (if any) does Ethernet over GRE (gretap) conform to?

commers · 08-11-2010, 04:43 PM

I have learned how to create an Ethernet over GRE tunnel using the following command example :"ip add link eth1 type gretap remote a.b.c.d local w.x.y.z" (available since 2.6.28). (1) Is there a corresponding RFC ? I cannot find any standard e.g. RFC which this conforms to, for example RFC 1701, 1702, etc. (2) Do standard routers (e.g. Cisco, Juniper) terminate this protocol or is it strictly Linux-to-Linux? If so, can someone identify the command line syntax or topic to search for, i.e. what do the vendors call it?

paulsm4 · 08-11-2010, 05:18 PM

Hi - GRE (Generic Routing Encapsulation) is RFC 1701:

http://tools.ietf.org/html/rfc1701
http://tools.ietf.org/html/rfc1702
http://tools.ietf.org/html/rfc4797

No - it's an open protocol, it is NOT "strictly Linux"

commers · 08-11-2010, 05:50 PM

Quote:

Originally Posted by paulsm4

Hi - GRE (Generic Routing Encapsulation) is RFC 1701:

http://tools.ietf.org/html/rfc1701
http://tools.ietf.org/html/rfc1702
http://tools.ietf.org/html/rfc4797

No - it's an open protocol, it is NOT "strictly Linux"

Paul,
Thanks for the reply. However, the first two RFCs above are very high-level, and the third one concerns BGP/MPLS. I am looking for the RFC which specifically covers encapsulating layer 2 over IPv4 GRE tunnels, packet format, etc. Also I'd like to know the overhead for such. Am I missing something?

paulsm4 · 08-11-2010, 06:46 PM

Hi -

There's nothing you can't find starting from either the information I gave you, or using this link:

http://tools.ietf.org/

I gave you the original RFC's (and an RFC for a common application of GRE), thinking it might be a good starting point. So you could take it from there.

Let me give you the most recent (AFAIK) RFC's related to GRE, if you'd prefer:

RFC 2784, RFC 2890

'Hope that helps .. PSM