Managing Storage Traffic with SDN (in IO converged networks)

Note: The basic idea of this paper comes from the thesis, introduces a kind of method similar to Sdn OpenFlow, and applies it to the FCoE network. This method of control flow can coexist with the SDN flow control method OpenFlow protocol, but it is not exactly the same as the data plane and control plane extending the OpenFlow protocol:)

Problem

integration of storage networks into virtual networks
Because data center resources require on-demand control, network virtualization and SDN have aggressively driven the data center network. However, there are still some problems with the full control of the network with software. There is a problem to achieve fine-grained control. Moreover, software control may not be as effective for high-speed reactions (high-speed traffic). Further, even though OpenFlow has recently become popular as a control-flow-level switch, there is not enough features to control the storage stream; it lacks the features to drill down into the stored packages.

Several problems with FCoE

There is a traffic bottleneck problem, as shown in:

There may be a network bottleneck for the FCoE topology of the NPIV proxy approach, but many of the traffic that passes through this bottleneck can be avoided.

Design ideas

Using the SDN method to control storage traffic

The basic idea is the combination of the traditional method and the Sdn method;
Considering the problem of particle size control, physical switch should provide fine granularity and high speed control.
If we deploy the Ethernet switch as reactive openflow interaction at that time, all packets from the unknown address will be sent to the controller, resulting in a high overhead of the control plane. This problem can be solved using the proactive method if we have node location information. On the other hand, SDN is not suitable for fault control, and we can use the reactive approach (FIPS processing) to control the FCoE stream, which is not very high and does not cause the controller to be too expensive.

Enhanced Storage flow control method
Lan,fcoe is basically not controlled by OpenFlow. OpenFlow can see the IP Source address and destination address, protocol, TCP port number and other information, however, does not recognize the FIPS field, such as d_id (Destination FC ID). Therefore, it is very important for the switch to handle the packet information of the storage stream.

Prototypes and Evaluations

prototypes
Platform: Converged fiber optic network, we use a fused fibre switch (self-produced). The cfabric consists of a switch blade and Tor switch and management software.
Consists of a switch firmware and a controller.

Switch firmware:
In addition to the basic switch functions, there are two features, one is to seize the FIP package to forward them to the controller, the second is to detect the FCoE stream. If the controller tells it how to forward the FCOE packet, follow the instructions of the controller and change the forwarding statement.

Additional switch configuration commands are used (self-developed) to achieve these features. Allows the external controller to control the flow (just like openflow). Is the part that needs to be added to FCoE processing.

Controller
Includes the main four functions: Analysis of the FIP package (to be able to capture the contents of the L3), the ability to determine the end location, the ability to calculate the appropriate route, the ability to send instructions to the switch. We are mainly used to describe the operation of the controller.

Summary: The main idea of the prototype is to enable the recognition of FCOE in the data plane, and then on the controller side can be implemented according to FCoE L3 (d_id) to forward. He lets the switch really become an FCOE switch (compared to the IP router).
First, the switch sends the FIP packets to the controller (the action that matches the Ethernet type). The controller then analyzes the FIP package and sends instructions to the switch for the FCoE transfer. The overall structure is as follows:

Reference documents:
[1] Shiraki O, Nakagawa Y, Hyoudou K, et al. managing storage flows with SDN approach in I/O converged networks[c]//globecom W Orkshops (GC Wkshps), IEEE. IEEE, 2013:890-895.

Managing Storage Traffic with SDN (in IO converged networks)