MLDesigner

A Flexible Switching Fabric Model

3-layer networking fabric for analysis of complex network switches

This flexible model of a 3-layer switching fabric can be configured to represent fabrics of different size. The model provides a single instance of each switch and processor and generates additional instances as specified by configuration parameters.

The system consists of:

Input Processors
First layer switches (S1)
P1 Processors that link S1s to S2s
Second layer switches ( S2)P2 Processors that link S2s to S3s
Third layer switches (S3)
Output Processors, and a
Control Unit.

In operation, an Input Processor (I) receives packets, processes it and contacts the Control Unit to get the address of a processor (P1) to which the packet should be forwarded. The control unit knows which P1 is free or least loaded and sends the appropriate header information to I. Each Input Processor is connected to two S1 switches and a S1 switches are connected in a Ring Topology, so a packet from any Input Processor can be sent to any P1 processor. Each S1 is connected to 4 P1 processors. Switches at each level (S1, S2 and S3) read the header of the packet and forward to the next switch or the next processor. P1 processors receive packets, process them and then contact the Control Unit to get the address of the optimal P2 processor, insert the header and forward the packet to S3 for delivery to the appropriate Output Processor, which forwards the packet to the appropriate port without Control Unit intervention.

The schematic below shows the basic structure of the fabric.

The top-level MLDesigner model is shown below (Figure 2).

The key components: Control Unit (Fig.3), processors (a single model is used for all four processor types) (Fig.4), switches (a single model is used for all three switch types) (Fig.5) and the traffic source (Fig.6) are shown below.