Ixia Black Book: SDN/OpenFlow

Introduction – Software Defined Networking
software-based networking architecture creates open multivendor markets as the
network operator can select different control and data plane vendors. The division of
the planes increases network reliability and security, creating the potential to lower
both CAPEX and OPEX costs while decreasing the complexity of networking hardware
and network management.
OpenFlow Basic
OpenFlow defines two main device types; a controller and a switch. The OpenFlow
controller talks to each OpenFlow switch over an IP connection (known as OF Channel)
and has the ability to program the forwarding table of the switch with flow-table entries.
These Flow Table entries are called Flows. A Flow has set of match fields and related
actions. A match fields define the packet match criteria for the switch. Match fields are
various protocol fields such as L2 MAC address, L3 IP address, VLAN address, etc. For
each set of Match, there is a corresponding Action associated with it. The action
defines what the switch supposed to do when packets matches the Match criteria. An
Action could set certain protocol fields such as VLAN address and/or forward the
packet to a port. A port could be a physical port or it could be virtual port number to
identify an operation such as flood.
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