GRE
Generic Routing Encapsulation (GRE) is a tunneling protocol that was first developed by Cisco. It can encapsulate a wide variety of network layer protocols within virtual point-to-point or point to multipoint links over an IP network.
Some characteristics of a GRE tunnel include:
- supports Multicast
- has no inherent security features
- is a fundamental component of DMVPN
- operates as a point to point tunnel or as a multipoint tunnel (mGRE)
- can carry a wide variety of protocols including
Links
https://networklessons.com/cisco/ccie-enterprise-infrastructure/how-to-configure-gre-tunnel-on-cisco-ios-router https://datatracker.ietf.org/doc/html/rfc2784 https://datatracker.ietf.org/doc/html/rfc2890
Links to this page:
- home
- ASA - object group protocol vs service
- DMVPN - IPsec encryption order of operations
- DMVPN - NHRP session attributes
- DMVPN - Phase 2 EIGRP neighbor adjacencies
- DMVPN - Phase 2 OSPF neighbor adjacencies
- DMVPN - Phase 2 and multicast traffic
- DMVPN - Using the GRE tunnel key
- DMVPN dual hub single cloud
- DMVPN
- ERSPAN
- Ethernet over IP (EoIP)
- FlexVPN spoke to spoke communication fails with IPSec tunnel
- GRE - Keepalives and VRF-aware tunnels
- GRE - Recursive routing error
- GRE - Understanding how keepalives work
- GRE MTU settings
- GRE Tunnel Addressing
- GRE and IPSec
- GRE tunnel and multicast
- GRE tunnel key operation with only one tunnel key configured
- GRE tunnels and how they transmit multicast packets
- IPsec - does it support multicast
- IPv4 - header protocol field
- MPLS-TE Tunnel and Recursive Routing
- MTU - Adjusting MTU to accommodate additional headers
- Multicast - routing over the Internet
- Networks - Spanning Layer 2 networks across remote sites
- OSPF in a GRE multipoint environment
- OSPF requirements for forming adjacency
- STP - port identification
- VRF sharing across multiple routers
- WAN - how to choose a WAN technology
- mGRE