.. _geneve-interface:

######
GENEVE
######

:abbr:`GENEVE (Generic Network Virtualization Encapsulation)` supports all of
the capabilities of VXLAN, NVGRE, and STT and was designed to overcome their
perceived limitations. Many believe GENEVE could eventually replace these
earlier formats entirely.

GENEVE is designed to support network virtualization use cases, where tunnels
are typically established to act as a backplane between the virtual switches
residing in hypervisors, physical switches, or middleboxes or other appliances.
An arbitrary IP network can be used as an underlay although Clos networks - A
technique for composing network fabrics larger than a single switch while
maintaining non-blocking bandwidth across connection points. ECMP is used to
divide traffic across the multiple links and switches that constitute the
fabric. Sometimes termed "leaf and spine" or "fat tree" topologies.

Geneve Header:

.. code-block:: console

  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |Ver|  Opt Len  |O|C|    Rsvd.  |          Protocol Type        |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |        Virtual Network Identifier (VNI)       |    Reserved   |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
  |                    Variable Length Options                    |
  +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

.. cfgcmd:: set interfaces geneve gnv0 address '192.0.2.2/24'

Create GENEVE tunnel listening on local address `192.0.2.2/24`.

.. cfgcmd:: set interfaces geneve gnv0 remote '172.18.204.10'

Specify the IP address of the other end of the tunnel.

.. cfgcmd:: set interfaces geneve gnv0 vni '1000'

:abbr:`VNI (Virtual Network Identifier)` is an identifier for a unique element
of a virtual network.  In many situations this may represent an L2 segment,
however, the control plane defines the forwarding semantics of decapsulated
packets. The VNI MAY be used as part of ECMP forwarding decisions or MAY be
used as a mechanism to distinguish between overlapping address spaces contained
in the encapsulated packet when load balancing across CPUs.

.. cfgcmd:: set interfaces geneve gnv0 mtu

Set interface :abbr:`MTU (Maximum Transfer Unit)` size.