6. Virtual Wall: Node Functionality Client (Windows) Client (Linux) Cl 1 | Cl 2 | Cl 3 | Cl 4 Client (Windows CE) Network Element Cl 1 | … | Cl n Network Element Impairment Node Impairment Node Network Element S 1 | S 2 | S 3 | S 4 Server (Windows) S 1 | … | S n Server Server (Linux)