User guide

OpenFlow Agent Overview Web Services, CLI Scripting, and OpenFlow
page 10-26 OmniSwitch AOS Release 8 Switch Management Guide May 2014
OpenFlow Agent Overview
OpenFlow is a communications interface defined between the control and forwarding layers that is used in
a Software Defined Network (SDN). OpenFlow essentially separates the control plane and the data plane
in the . Traditionally, es and routers have made decisions on where packets should travel based on rules
local to the device. With OpenFlow, only the data plane exists on the itself, and all control decisions are
communicated to the from a central Controller. If the device receives a packet for which it has no flow
information, it sends the packet to the Controller for inspection, and the Controller determines where that
packet should be sent based on QoS-type rules configured by the user (drop the packets to create a fire-
wall, pass the packets to a specific port to perform load balancing, prioritize packets, etc).
The Omni can operate in AOS or OpenFlow mode, including a modified OpenFlow mode known as
Hybrid mode. AOS will designate the ports managed/controlled by AOS or by OpenFlow on a per-port
basis. By default, ports are managed/controlled by AOS.
The following are the key components available on an Omni for OpenFlow support.
OpenFlow Logical
An OpenFlow logical consists of a portion of the 's resources that are managed by an OpenFlow Control-
ler (or set of Controllers) via the OpenFlow Agent. Logical es can be configured on an Omni, with each
logical supporting separate controllers. A logical has a VLAN, physical ports, and/or link aggregate ports
assigned to it. All packets received on these ports are forwarded directly to the Openflow agent. Spanning
tree and source learning do not operate on OpenFlow assigned ports.
OpenFlow Normal Mode
In Normal mode, the logical operates as per the OpenFlow standards.
OpenFlow Hybrid (API) Mode
In Hybrid mode, logical acts as an interface through which the Controller may insert flows. These flows
are treated as QoS policy entries and offer the same functionality. A Hybrid logical operates on all ports,
link aggregates, and VLANs not assigned to other OpenFlow logical es.