Voice Over IP (VoIP): Status and Industry Direction
Jim McEachern, Carrier VoIP Standards Strategy, Nortel Networks
This tutorial will examine evolving standards and architectures for VoIP. The term "VoIP" implies a single, unified standard - but this is not the case. A range of protocols have been adopted and deployed in a variety of applications, all under the banner of VoIP.
The tutorial will begin by reviewing some of the major VoIP standards that have been deployed to date. Strengths, weaknesses, and applications for these standards will be considered. This will set the stage for a discussion of the current focus of VoIP standards work - the definition of a converged IP multimedia network standard. This goal is being actively pursued by 3GPP, ETSI TISPAN, ATIS, ITU-T, and others. This tutorial will discuss the converged IP multimedia architecture that is emerging from these activities, and some of the key values it will provide to carriers. We will identify and discuss open issues, such as QoS, E-911, Emergency Telecommunications Services, and regulatory requirements currently under study. The issues and opportunities associated with carrier-to-carrier packet based interconnect will also be considered. This tutorial is intended to provide an overview of where VoIP has been, where it is today, and where it is going.
Outline
1. VoIP architectures & standards
This section will present a brief review of VoIP to date. It will
identify, briefly discuss, and put into context, the following:
2. VoIP standards direction.
Many SDOs (Standards Development Organizations) are now developing a
similar NGN standard for VoIP. The emerging solution is based on the
3GPP IMS (IP Multimedia Subsystem) with extensions to include a range of
access networks. This work is being progressed by 3GPP, ETSI TISPAN,
ATIS NGN FG, and ITU-T FG-NGN. In this section we will discuss:
3. QoS
It is widely recognized that acceptable QoS will be critical for VoIP to
fully replace the existing PSTN. This section will discuss QoS
requirements such as the ability to dynamically provide differentiation
based on service type. It will also discuss the need for mechanisms to
predict and quantify the level of QoS expected. Several techniques for
implementing QoS will be reviewed, including:
4. Carrier Grade VoIP
When VoIP is considered as a replacement for primary line PSTN service,
additional requirements are typically identified. This section will
identify and discuss requirements such as:
5. ENUM
The role of ENUM in VoIP networks will be briefly discussed. This will
include a discussion of what ENUM can, and cannot, provide for VoIP.
6. VoIP Carrier Interconnect
VoIP networks will require interconnection to the legacy PSTN, and
packet based interconnection to other VoIP providers. The specification
of this interconnection will determine the cost and the functionality of
the resulting service. This section will identify some of the primary
interconnection options, and discuss the implications of each.
7. Open issues
This tutorial will finish with a discussion of some of the open issues
in VoIP standards and networks.
Speaker Bio
James McEachern is responsible for defining standards strategy for the
Carrier VoIP products, at Nortel Networks. For the past 20 years, he
has been involved in network and product planning, with experience
covering SONET/SDH, high-speed access (DSL, cable, and fiber), fixed
wireless access, operations, VoIP, Data Networking, and Service
Management. He is currently a member of the Board of Directors of the
Multiservice Switching Forum (MSF), and the editor of ITU-T
Recommendation Y.1414 (Voice Services over MPLS).