Generalized Routing Encapsulation (GRE) and IP-IP Encapsulation
- RFC 1701, Generic Routing Encapsulation (GRE)
- RFC 1702, Generic Routing Encapsulation over IPv4 Networks
- RFC 2003, IP Encapsulation within IP
- RFC 2890, Key and Sequence Number Extensions to GRE. The JUNOS software supports the key field, but not the sequence number field.