# Honeycomb Topology Generator The RAN simulator comes with an accompanying utility that generates a RAN topology YAML file that is ready to be loaded by the RAN simulator. This utility generates a hexagonal grid of RAN towers (E2 Nodes), each with a prescribed number of cells with equal arc of coverage. The following is the command-line usage: ``` Usage: honeycomb topo outfile [flags] Flags: --cell-types strings List of cell size types (default [FEMTO,ENTERPRISE,OUTDOOR_SMALL,MACRO]) --controller-addresses strings List of E2T controller addresses or service names (default [onos-e2t]) --controller-yaml string if specified, location of yaml file for controller --deform-scale float scale factor for perturbation (default 0.01) --earfcn-start uint32 start point for EARFCN generation (default 42) --gnbid-start string GnbID start in hex (default "5152") -h, --help help for topo -a, --latitude float Map centre latitude in degrees (default 52.52) -g, --longitude float Map centre longitude in degrees (default 13.405) --max-collisions uint maximum number of collisions (default 8) -d, --max-neighbor-distance float Maximum 'distance' between neighbor cells; see docs (default 3600) --max-neighbors int Maximum number of neighbors a cell will have; -1 no limit (default 5) --max-pci uint maximum PCI value (default 503) --min-pci uint minimum PCI value -i, --pitch float32 pitch between cells in degrees (default 0.02) --plmnid string PlmnID in MCC-MNC format, e.g. CCCNNN or CCCNN (default "315010") -s, --sectors-per-tower uint sectors per tower (default 3) --service-models strings List of service models supported by the nodes (default [kpm/1,rcpre2/3,kpm2/4,mho/5]) --single-node generate a single node for all cells -t, --towers uint number of towers --ue-count uint User Equipment count --ue-count-per-cell uint Desired UE count per cell (default 15) ``` Most options have reasonable defaults and only the `--towers` is mandatory. Here is an example of how to run the command to generate topology for a network with PLMNID of `314628` with 10 E2 nodes (towers), each with default number of 3 cells. ``` go run cmd/honeycomb/honeycomb.go topo --plmnid 314628 --towers 10 pkg/utils/honeycomb/sample.yaml ``` Here is the [output generated by the above command](../pkg/utils/honeycomb/sample.yaml). Note that for options that are lists, like `--controller-addresses` for example, you can specify them as comma-separated values `--controller-addresses onos-e2t-1,onos-e2t-2` or you can simply repeat the option `--controller-addresses onos-e2t-1 --controller-addresses onos-e2t-2`. The `--max-neightbor-distance` parameter (specified in meters) works as follows: if after traveling this distance along a center line of the coverage sector, the endpoint falls within half this distance from another cell's such endpoint, those two cells will be considered neighbors. This is to assure that the two coverage arcs converge sufficiently. Note that the utility relies on random number generator and therefore its output is not deterministic.