This chapter describes configuring GRE tunnels, covering encapsulation, decapsulation, and NVGRE load-balancing for Cisco 8000 series routers.
GRE tunnels
This topic describes Generic Routing Encapsulation (GRE) tunnels on the Cisco 8000 Series Router, including how they encapsulate a payload of one protocol inside an outer IP packet for delivery between two tunnel endpoints.
GRE encapsulation and decapsulation over BVI
This topic describes GRE encapsulation and decapsulation over a Bridge-Group Virtual Interface (BVI) on the Cisco 8000 Series Router.
Unidirectional GRE encapsulation (GREv4)
This topic describes unidirectional GRE encapsulation (GREv4) on the Cisco 8000 Series Router, where the tunnel encapsulates an IPv4 or IPv6 payload inside a GRE header for transport across an IP network.
Unidirectional GRE decapsulation (GREv4)
This topic describes unidirectional GRE decapsulation (GREv4) on the Cisco 8000 Series Router, where the router strips the outer GRE header and forwards the inner IPv4, IPv6, or MPLS payload to the next-hop router.
ECMP and LAG hashing for NVGRE flows
This topic describes ECMP and LAG hashing for NVGRE flows on the Cisco 8000 Series Router, which lets transit routers load-balance NVGRE traffic across ECMP and LAG paths using the GRE payload.
Network Virtualization using Generic Routing Encapsulation hash field selections
This topic describes Network Virtualization using Generic Routing Encapsulation (NVGRE) hash field selections on the Cisco 8000 Series Router, which control whether NVGRE inner payload fields are included in the load-balancing hash calculation on Cisco Silicon One Q100 and Q200 ASIC-based systems.