1. Simulation limitations

With respect to a real network architecture, we have to consider a simplified configuration.

1.1. Configuration with modems

First we consider only one user, so one unique remote terminal is used in the simulation.

Then, PEPsal is installed only on the remote terminal side. Indeed the use of PEPsal allows the user to have a better experience and as there is no user in the Hub side, we decided to don't use it here.

Moreover the delay due to the satellite link is 300ms on the overall link. Consequently, we added a delay of 300ms for all packets leaving the remote terminal interface and 300ms for all packets leaving the hub interface. Thereby we achieve a RTT of 600ms.

Modems use IP forwarding, in other terms when a modem receives a packet from the router, it checks on the destination address. If the packet is not destinated to the modem, the modem will forward it to the other modem along the emulated satellite link. Then, when the packet arrives at the second modem, there is an other analyze of detination address. If the second modem is not the recipient, the packet will be forwarded to a gateway. The gateway is defined before starting the simulation.
Note that there is only one gateway, so it does not allow to have two subnet connected directly to the modem.

Figure 1: Equipements to simulate satellite link with modems.

1.2 Configuration without modems

Due to difficulties in configuring MDM 6000 modems, we had to consider a case without modem. Satellite link is traduced only with delay. The following figure illustrates the architecture.

Figure 2: Equipements to simulate satellite link without modem.