OpenMUL PRISM – connecting legacy world with SDN!

The major problem with legacy network equipment which spawned the SDN
movement has been the lack of simple and centralized management plane all the
while making the network highly agile. Various legacy devices like IP routers
had different and proprietary control plane to data plane interfaces and hence it
became impossible to centralize the control plane. Even the north bound
interfaces on top of control planes like SNMP, netconf varied wildly for each

One of the major USP of Openflow has been standardized interface between
control and data plane. It gives us immense potential to centralize control planes
and provide centralized control to network operators.

Having such a separation is great but is it a good idea to reinvent the way
networks all around the world have been designed?

The simple answer-we don’t need to redesign the networks. Because networks
still need to talk, say, OSPFv2 or BGPv4. These are built into DNA of modern
network infrastructure. But, Openflow can be definitely be used to solve the
centralized management problems. Effort should be put to bring more devices
under centralized management umbrella while letting interface to the external
world unchanged i.e. use OSPF, BGP etc as is.

Read the whitepaper here

The open-source code will be available in upcoming release of OpenMul ‘Concave’ in Jan 2015.

Loop Detection feature of OpenMUL

This article explains the spanning tree implementation of MUL SDN Controller.


This feature is used when there are one or more occurrences of loop in the network. Spanning Tree implementation makes sure that there are no loops when there are two or more paths to reach a particular network element. Once a loop is occurred due to a broadcast stream then it can be deadly for the network. So, this makes Loop Detection feature an antidote for any network.



Loop detection module uses LLDP for implementing Spanning Tree.  When network element is added to a network, MUL SDN controller sends LLDP packets to every port of the attached network element. By doing this, MUL Controller gets the information about the network topology.

After getting all the information about the neighbours, port states needs to be decided.

Details of the process are :  Continue reading