Quality of Service (QoS) is a requirement for latency sensitive, real time applications such as voice, particularly Voice over IP (VoIP), as well as real time video services, and multiparty applications (Push to Talk (PTT), Video Sharing, Video Conferencing and so forth).
When applied to a single access technology, the standards are evolving with what looks to be cogent solutions to provide the required QoS and Latency to ensure the proper end-user experience. 3GPP R7 has taken leaps in this area, as has 3GPP2, Packet Cable, TISPAN, and other technology groups using IMS.
The complication faced by carriers is how to ensure and manage QoS in scenarios that go beyond a single provider, and a single technology. For Example:
- Wireless carriers deploying multiple access technologies
- Wireless carriers (3GPP/2) interfacing with Wire line and Fixed carriers (TISPAN/Packet Cable)
- Peering of carriers deploying similar access technologies, but different methods for coding and transports (i.e EVRC<G711 codecs)
- Transcoder free operation through a peered IMS domain (when/how codec shift is achieved, while maintaining QoS and Low Latency
- Implementing differential interfaces to manage QoS such as DIAMETER Rx/Tx/Gx/Gy/Ty
- Maintaining low latency with multiple transcoding operations
While the standards continue to evolve, starting with 3GPP and flowing to the other standards bodies, little attention is given to how to properly maintain QoS in these scenarios. As roaming, both national and international, is paramount, thought must be given as to how carriers manage the grant of QoS, and the subsequent allocation of precious resources, to roaming parties, or to subscribers not part of their specific subscriber base. Questions raised:
- Can priority for QoS be granted to a roaming subscriber; if the access technology is reaching a blocking stage (can/should the roamer be given the QoS promised by the home network?
- How should Service Level Agreements evolve to ensure proper QoS and latency for all types of “visiting” subscribers?
- Should operators actively pursue tiered services, based upon a subscriber’s location, payment structure, or a combination of both?
- Just how effective to the current standards address quality assurance, and how do carriers fill in the missing pieces?
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