Assignment description: "Quality control of Voice-over-IP"

External assignment at SpeakUp, Enschede

Voice-over-IP (\"VoIP\") technology is increasingly getting attention as an alternative to the ordinary telephone service that is currently dominating the telephony market for both business as well as individuals. In VoIP, telephony data is sent through the Internet between VoIP applications (e.g., a PC running a piece of software, or a VoIP phone).

It is of crucial importance to broad adaptation of VoIP technology that the quality of VoIP connections -as perceived by the user- is sufficient. Quality in this respect refers to availability and quality of speech. The quality of VoIP is influenced by:
- the equipment.
- the VoIP protocol, for instance choice of codecs.
- the underlying technology, such as: the IP packet, available bandwidth, latency and delay variation.

In this assignment, the student will assess the quality of VoIP (primarily as it is perceived by users) under different (realistic) circumstances, including (but not limited to): various codecs, different networking environment (high/low latency, high/low available bandwidth, etc.) and various types of telephony equipment. The focus is on:
1. Realistic home and small to middle-sized business networking environments (say DSL up to 100 Mbps Ethernet connections).
2. Inter-carrier VoIP traffic (e.g. ENUM and peering traffic).

The student will also investigate whether the use of Quality of Service technology will further stretch the `usability\' of VoIP, especially during times when resources are scarce (e.g. DiffServ, IntServ or 802.1p/q VLAN based QoS).

The following approach is proposed for this assignment:
1. Literature study, focusing on VoIP technology, Quality of Service and perceived quality for speech.
2. Various experiments carried out (following the outline set above) to get quantitative figures on the `usability\' of VoIP.
3. Recommendations given on (especially) the minimal requirements for networks/links to support VoIP.

SpeakUp will provide the student with the equipment necessary to perform the above tasks.