Routers¶

Routers are the central switching elements in the Network-on-Chip. They route packets between Endpoints (via Network Interfaces) and other Routers. FlooGen supports generating routers with configurable port counts (degree), routing algorithms, and topologies (meshes, trees, or irregular graphs).

Configuration¶

Routers are defined under the routers list in the configuration file.

Parameters¶

Parameter	Type	Description	Required	Default
`name`	String	Unique identifier for the router. Used in connection definitions.	Yes	-
`array`	List[Int]	Defines a grid of routers (1D or 2D). E.g., `[4, 4]` creates a 4x4 mesh of routers.	No	`None`
`tree`	List[Int]	Defines a tree topology structure. The list specifies the branching factor at each level.	No	`None`
`degree`	Integer	Override the number of input/output ports on the router.	No	`None`
`auto_connect`	Boolean	If true and `array` is specified, FlooGen automatically generates mesh connections (North, East, South, West) between the routers.	No	`True`
`xy_id_offset`	Map/Int	Offsets for XY coordinates or IDs, used to manually adjust the logical position of the routers in the network.	No	`None`

Examples¶

Single Router¶

A standalone router, useful for star topologies or small clusters where everything connects to a central point.

routers:
  - name: "router"

Mesh Router (2D Array)¶

To generate a Mesh NoC, you define an array of routers. By default, auto_connect: true will automatically create the grid links between them.

routers:
  - name: "router"
    array: [4, 4] # 4x4 Grid
    auto_connect: true # Default

Tree Topology¶

For tree networks, the tree parameter defines the structure. For example, a binary tree with 2 levels of switches.

routers:
  - name: "tree_router"
    tree: [2, 2] # Binary tree depth definition

Disabling Auto-Connect¶

If you want to define a custom topology using an array of routers (e.g., a torus or a specific irregular grid) without the default mesh connections, you can disable auto_connect and define connections manually.

routers:
  - name: "custom_router"
    array: [2, 2]
    auto_connect: false # Manual connections required

Override router degree¶

You can override the default port count of a router by specifying the degree parameter. This is useful in XY-Routing which always assumes 5 ports (N, E, S, W, Local). Regardless of whether the router is on the edge or corner of the mesh, it will still have 5 ports.

routers:
  - name: "router"
    array: [4, 4]
    degree: 5