The Effect of Voice Packet Size on End-To-End delay in 802.11b Networks

Voice over IP (VoIP) uses the existing data networks to support voice services. It has a broad appeal in that it is currently unregulated and calls can be placed free of cost to any part of the globe. The integration of voice traffic with data traffic opens up opportunities for new revenue stream for Internet Service Providers. However, in mixing data types the constraints on each data type must still be met and unlike regular data, voice networks are chiefly limited by end-to-end delay. In the case of packet switched networks delay becomes a determining factor in the quality of the voice call and therefore the success of VoIP. At the same time, WLANs are becoming widely adopted due to the simplicity in installation and convenience offered. Advancement in technology now enables WLANs to provide most of the facilities provided by their wired counterparts with the added benefit of mobility at a very low cost. The benefits of combining IP telephony and WLANs can be effectively utilized if the control over end-to-end delay can be achieved. In conventional IP telephony the voice packets travel across the wired Internet. We developed a study in which the final hop on each end of the communication channel is a wireless 802.11b network. Results show that with a wireless network at the transmitting end the delay characteristics change considerably