Resumen de Quality of service (QoS) of voice over MAC protocol 802.11 using ns-2

Dileep Kumar, Yeonseung Ryu, Hyuksoo Jang

• Transmitting voice through IP data network can provide significant cost savings. However if not managed properly, voice quality can degrade due to data network congestion. Voice over IP (VoIP) is gaining an ever increasing popularity. As such, it nowadays represents one of the most studied test applications in the performance evaluation of wireline and wireless networks in which the IEEE 802.11 distributed coordination func tion protocol or enhanced DCF protocol is used. However, since both DCF and EDCF are contention-based medium access control protocols, it is difficult for them to support the strict QoS requirement for VoIP.

  In this paper we will investig ate QoS indications (for voice packets), Improvement of NS2 network simulator in order to simulate statistical QoS in 802.11 MAC and Show that Uplink/Downlink problem exists in EDCF and suggest different solutions using QoS parameters (DIFS, CWmin and PF).