Software Defined Networking
SDN is short for software defined networking. Software defined networking
(SDN) is an approach to using open protocols , such as open flow,
to apply globally aware software control at the edges of the network to
access network switches and routers that
typically would use closed and proprietary firmware.
Benefits of Software Defined Networking
Software defined networking
offers numerous benefits including on-demand provisioning, automated load
balancing, streamlined physical infrastructure and the ability to scale network
resources in lockstep with application and data needs. As noted on enterprise
networking concept, coupled with the ongoing virtualization of servers and
storage, SDN ushers in no less than the completely virtualized data center,
where end-to-end compute environments will be deployed and decommissioned on a
whim.
An open flow switch separates these
two functions. The data path portion still resides on the switch, while
high-level routing decisions are moved to a separate controller, typically a
standard server. The Open-Flow Switch and Controller communicate via the
OpenFlow protocol, which defines messages, such as packet-received,
send-packet-out, modify-forwarding-table, and get-stats.
The
data path of an OpenFlow Switch presents a clean flow table abstraction; each
flow table entry contains a set of packet fields to match, and an action (such
as send-out-port, modify-field, or drop). When an OpenFlow Switch receives a
packet it has never seen before, for which it has no matching flow entries, it
sends this packet to the controller. The controller then makes a decision on
how to handle this packet. It can drop the packet, or it can add a flow entry
directing the switch on how to forward similar packets in the future.
In
other words it provides one, open-standard methodology of optimizing traffic,
end-to-end, and in the near future SDN is bound to change the way communication
network is managed.
Shekhar Singh
Asst. Prof.
Deptt of CSE
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