OpenSAND emulates a satellite network connected to terrestrial entities. Each entity of this network must run on their own machine or netnamespace and be interconnected on a specific, ideally separate, subnetwork. Terrestrial entities are connected to the rest of the network using TAP interfaces. From the point of view of the network, OpenSAND acts as a black-box between these TAP.

Configuration of how packets are routed to or from the TAP interface is outside the scope of the opensand binary but tools and examples are provided to reduce the learning curve and help users to quickly setup and discover OpenSAND capabilities.

OpenSAND CLI

The opensand_cli folder is a collection of Makefiles to easily configure your network on a machine and run a simple configuration of OpenSAND once done.

Note that these are example configurations for a given purpose and in no way mandatory or a perfect fit. It is necessary to edit them and input values that make sense to your own network architecture. Additional changes may be needed to adapt to your specific network needs.

OpenSAND Network

The opensand_network folder provides a Python module to easily create TAP, bridges and routing on a machine or inside a net-namespace. This utility is provided in the opensand-network debian package for convenience.

Using the opensand-network tool to create netnamespaces will save you the burden to interconnect them all, but will force some design choices on your network. This is a tradeoff, use where appropriate.

opensand-network

This script provide an API to easily manage net-namespaces for your OpenSAND processes. This allows to easily run your entire emulation on a single machine. It is comprised of 3 main commands:

sudo ./opensand-network setup -g 6 -s 0 -t 1 2 3

This command will create a net-namespace for a gateway with an ID of 6, setup a bridge and a tap inside; it will create a second net-namespace for a satellite with an ID of 0; lastly it will create 3 net-namespace for a terminal, with respective IDs of 1, 2, and 3, and setup a bridge and a tap inside each of them. Emulation addresses are of the form 192.168.18.ID and TAP are created with a name of opensand_tap and addresses of the form 192.168.63.ID.

sudo ./opensand-network launch gw 6 path/to/topology.xml path/to/infrastructure.xml path/to/profile.xml
sudo ./opensand-network launch sat 0 path/to/topology.xml path/to/infrastructure.xml
sudo ./opensand-network launch st 1 path/to/topology.xml path/to/infrastructure.xml path/to/profile.xml
sudo ./opensand-network launch st 2 path/to/topology.xml path/to/infrastructure.xml path/to/profile.xml
sudo ./opensand-network launch st 3 path/to/topology.xml path/to/infrastructure.xml path/to/profile.xml

These commands will each run an OpenSAND process into the designated net-namespaces and wait for completion. Ideally you want to run them in a dedicated terminal each.

sudo ./opensand-network clean

This command will remove all the net-namespaces created previously.

Note that all these commands need to be run as root because they all use the ip netns exec command internally that requires root privileges.

Extra options exists for all these commands, use the --help flag to learn about them.

An additional command also help to define networks to deal with ISL communications:

sudo ./opensand-network isl 2 9

This command create a network usable between the satellites with IDs 2 and 9. It offers a TAP named isl_<count>_tap where count is the amount of isl commands ran for that satellite, and addresses of the form 10.10.ID. on each satellite that are meant to be used in an Interconnect block (see the user manual on ISL configuration).

Intégration with opensand_cli

You can use the configurations presented in the opensand_cli folders and launch OpenSAND through the opensand-network script. To do so, issue the make generate-xml command in the opensand_cli folder of your liking and indicate the path to the generated files to the opensand-network launch command.