Can the Production Network Be the Testbed?

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1. Questions

To evaluate a new feature or bug fix must trade-off realism and cost where testbed does well. But current testbeds are either beyond the budget of the most researchs or incomplete.

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2. Solution

The authors propose a prototype named FlowVisor, and come true. FlowVisor aims to use production network as a testbed.

FlowVisor is a network virtualization tool based on OpenFlow. It can divide physical network into several logical networks, so as to realize virtual network partition.

It provides administrators with the ability to manage networks by defining flow rules rather than adjusting routers and switches configurations.

As the management program relies on the standard x86 command to the server virtualization, FlowVisor uses standard OpenFlow instruction set to manage OpenFlow switches, these instructions set a low level rules, such as how to based on the packet characteristics in header to forward packets.

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3. FlowVisor Design

(图片引用自SDNLAB http://www.sdnlab.com/3081.html)

Implementation methods include four aspects.
- Slicing network resource in terms of topology, bandwidth, forwarding Tables, device CPU.
- Every slice has control over flows, called its flowspace. Users can add and remove their own flows in flowspace at any time, which don’t affact others.
- Every slice has its own distinct, programmable control logic. The FlowVisor interposes between data and control planes by proxying connections between OpenFlow switches and each slice controller.
- Slices have a definition policy language who specifies the slice’s resource limits, flowspace, and controller’s location.

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4. Tests

In Scalability, comparison between observed workload and synthetic workload show that FlowVisor scales beyong our current requirement and workload.
In performance, results show that adding the FlowVisor causes an average overhead that for port status responses of 0.48 milli seconds, which isn’t bad.
In Isolation, FlowVisor is like a filter and slices bandwidth easily, but not perfect in device CPU.

5. Disadvantages

FlowVisor is based on OpenFlow, nor ForCES or OVSDB. It has few hardware capabilities available, which limits the flexibility.
The isolation in device CPU isn’t perfect.
The title includes production network, but the network is not big that only is a campus network who has tens middle-boxes. It isn’t enough to real big production network.

6. Advanced

Firstly, I will try to achieve the isolation in device CPU, so the industry could take it as quality assurance of new products. But by the chip’s update, the isolation isn’t important, espetially the rise of Edge Computing.
Secondly, like OpenDaylight, I will achieve the testbed to support OVSDB and other underlying protocols.