Motivation

There is a continued need for guidance on general transmission planning and keeping it up with technological evolution. Especially in light of the migration of modern telecommunication networks towards packet-based technologies (NGN), replacing traditional circuit-switched systems, guidance is needed on transmission planning with respect to heterogeneous and interconnected networks.

With NGN the differences between voice (voiceband) services and data services are becoming blurred. For transmission planning with respect to the network performance of services the point of interest is whether the connection will be transparent and what delay will occur. This makes it more important to study the effect of delay on data services/application. For the time being there is no detailed information on this topic or even a planning tool available.

Furthermore due to the migration towards packet-switched networks the functionality and intelligence of the networks is shifting towards the terminal. The impacts of this development on transmission planning need to be studied and specified. Guidance is needed on how voiceband data and multimedia services can be planned reliably in NGN infrastructures.

As IP technology is introduced into the PSTN, attention is being given to the TCP/IP protocol suite for carrying voiceband services (VoIP). This technology will affect the way that operators think about transport and switching (routing) in their networks, and will have a major impact on the range of services that are available to end users. Issues and guidelines for transmission performance necessary to ensure high end-user satisfaction must be reconsidered in light of this shift in the basic technology of speech and voiceband services.

The deployment of multiple VoIP islands interworking via the conventional PSTN will be a natural consequence of switch deployment practice. A network or service provider might wish to deploy VoIP as a PSTN replacement to deliver PSTN-type voiceband services such as speech, facsimile and voiceband data. Or, a network or service provider might wish to deploy VoIP as a new type of voice service. This will lead to multiple VoIP islands within a single carriers' network as well as islands which arise due to calls which are routed through multiple operators, and raises the issue of how to ensure a satisfactory level of speech transmission performance through a concatenation of multiple IP domains which may individually deploy different QoS control mechanisms.

The following major Recommendations, in force at the time of approval of this Question, fall under its responsibility:

G.101, G.108, G.108.1, G.108.2, G.113, G.114, G.131, G.172, G.1020

Question

Study items to be considered include, but are not limited to:

• Transmission planning rules for voiceband, data and multimedia services taking into account that end-to-end connections are established via heterogeneous and interconnected networks with different transmission technologies.
• Studying the effects of introducing IP technology into the PSTN to carry VoIP.
• Identification of strategies for avoiding excessive numbers of VoIP islands by deploying equipment and planning routing intelligently.
• Quantification of the effects of interworking between multiple IP domains on VoIP transmission performance.
• Identification of fundamental transmission parameters (e.g. packet loss, packet delay variation, echo) relevant to IP-based networks and quantification of the impact on end-to-end transmission quality of these transmission parameters.
• Determination how frame slips, random bit errors, and packet loss should be incorporated into the transmission planning process for speech and non-speech signals.
• Studying the effects in cases of service handover in order to elaborate transmission planning guidelines and performance considerations (like e.g. allowable packet loss and handover latency during handover).
• Studying the effects of the transmission delay on voiceband services including non-speech signals and Push-to-talk over cellular (PoC) applications.
• Studying the effects of conferencing facilities, i.e. multiple way communications, on voice streams, especially on the mixed-mode operation between narrowband (NB) voice streams and voice streams with higher bandwidths.
• Determination of the impairment effect of each new coding algorithm, so that it can be considered in the context of Recommendation G.113.
• Determination whether G.113 can be enhanced by its extension to include other impairment factors.
• Recording, study and classification of stationary/non-stationary noise, that may lead to revise noise measures in P.561, and help producing a noise model to be included in the E-Model.
• Considerations on how to help measure and mitigate climate change.

Tasks

Tasks include, but are not limited to:

• Maintenance and enhancement of Recommendation G.1020.
• Development of new Rec. G.TrIP-Islands, providing guidance on transmission planning for interconnected IP-based networks supporting PSTN and VoIP services.
• Frequent update of Appendix I to G.113.
• Revision of G.101, G.113, G.114, G.131, G.172 as needed.
• Creation of a new Recommendation, providing guidance on transmission planning and performance for service handover.
• Creation of new Recommendations on transmission planning aspects as needed.

An up-to-date status of work under this Question is contained in the SG 12 Work Programme http://www.itu.int/ITU-T/workprog/wp_search.aspx?isn_sp=545&isn_sg=551

Relationships

Recommendations: G.100-series, G.1000-series, G.170-series

Questions: 2/12, 3/12, 8/12, 14/12

Study Groups: ITU-T SG 11, SG 13, SG 15, SG 16

Standardization bodies: IETF, ETSI STQ, ETSI TISPAN