I am new member of Network Engineering site!
These days I am interested in GRE tunneling.
I know that GRE is developed by CISCO and many routers produced by CISCO and Juniper support GRE tunneling.
But I want to know other routers or firewalls support GRE tunneling.
How can I know whether some routers support GRE if there's no mention in product specification without testing by myself?
I also wonder that GRE is standard or used generally in network industry or not.