Response to ART’s public call for comments on Voice-over-IP
Com21 Background:
Com21 is a leading Voice-over-IP equipment manufacturer for
future Voice-over-IP services over the Cable TV network.
Com21 is also a vendor author in PacketCableTM, an initiative undertaken
by CableLabs to establish a set of specifications to offer packetized voice
and video over a Cable TV access network in North America. Cablelabs specifications
are provided as input to international standards organisations such as ITU and
ETSI.
In cable modem access equipment, Com21 is the #1 vendor in Europe. In particular,
in France, France Telecomm is Com21’s largest customer.
To date, Com21’s ComUNITY Access Systems cable modem equipment have passed over
9.2 millions households worldwide.
Question 1: Architecture, Equipment, Standardisation
1.1 - What type of Voice over IP services are there and what are the features o f each service? How do they enable a telephone service to be provided over the Internet ? What architectures and techniques are used?
The current type of Voice-over-IP services are based on the following architecture: call origination and termination are based on Public Switched Telephone Network access but the voice signals are transcoded from circuit switched mode to Voice-over-IP for carriage on IP-based Inter-eXchange Carriers (IXC) backbone networks. In the United States, IXC IP backbones are currently provided by Qwest and Level 3 Communications.
The features of such Voice-over-IP services can include those of CLASS features if the end-user devices are standard 2500 telephone station sets connected directly to PSTN networks. CLASS features signaling are preserved under such arrangements.
In the to-be-deployed Voice-over-IP services over the Cable TV network in North America, PacketCableTM specifications dictate the following MANDATORY CLASS features:
Call waiting
3-way calling
Call forwarding
Call Transfer
Speed Dialing
Return Call
Repeat Call
Call Block
Caller Name and Number
Caller Name and Number Privacy
Voice Mail
Virtual second line (multiple lines)
Message waiting indicator (email/voice mail notification)-"stutter"
dial tone, visual "message waiting" lamp or "Pop-up" notification
(multimedia PC)
Alternate billing methods (collect call, third number billed, credit card
etc.)
Desired OPTIONAL features include:
Voice encryption
Unified messaging
ISDN feature set
Integration of PacketCableTM directory services with personal address
book (PC) Direct connection from web browser to customization and self-provisioning
facilities, particularly for rules-based management services (PC)
Voice recognition interface (PC)
Smart card interface
1.2 What equipment is used ? Are the interfaces standardised or proprietary? What is the regime for industrial property rights ?
Equipment used in the subscriber premises includes a VOIP gateway with embedded Cable Modem (CM) and one or more interfaces to 2500-style telephone station sets. The VOIP gateway may also include an interface for the subscriber’s local area network data traffic. Equipment such as PCs or LAN connected embedded devices may also exist in the customer premises for supporting VOIP telephony service.
Equipment used in the backbone includes PSTN gateways that interface PSTN networks with IP-based IXC backbones and centralized call management servers that perform a role in implementing CLASS features, billing, and provisioning services like today’s central office switches. Since Com21 is not a vendor for PSTN gateways or call management servers, we have no input about the standards development in the PSTN or VOIP back-office arena.
2.1 - How is voice transmission quality of service (QoS) measured, for each type of service, and which indicators and criteria are used?
Voice transmission quality measurement indicators and criteria used generally include packets loss, latency and jitter.
2.2 - What is the current level of QoS in terms of speech quality, availability etc. ?
Information not available.
2.3 - Are there any standards that guarantee interoperability and quality of service? If so, which standards? What is the status of these standards?
Com21 is a vendor author in PacketCableTM, an initiative undertaken by CableLabs to establish a set of specifications to offer packetized voice and video over a Cable TV access network in North America.
For Com21’ s proprietary cable modem systems ComUNITY Access Systems, Com21 plans to make its Voice-over-IP equipment fully interoperable with PacketCableTM defined specifications and standard equipment.
In PacketCableTM, there are four types of specifications that govern Voice-over-IP over cable TV network.
- Simple Gateway Control Protocols or Multimedia Gateway Control Protocols that are used between a Call Management Server to set up calls with an embedded client in cable modems on the customer premise side.
- Quality of Service Protocols which includes QoS signaling protocols to classify traffic and QoS traffic management functions to be applied to classified traffic for priority, constant-bit-rate real time polling, constant information rate etc.
- Media streaming protocols that map voice codecs and video signals into IP packets.
- Provisioning and network management protocols to provision and operate a VOIP network.
PacketCableTM is also involved in IETF MEGACO, ITU,
and ETSI in terms of influencing and/or adopting available standards where applicable
to the cable environment.
PacketCableTM Phase I specifications will be finalized in Q2’99.
PacketCableTM is also working together with the DVB standards bodies
to explore adapting these specifications for DVB-based cable modems being deployed
in Europe.
Question 3 : Networks
3.1 - What kind of networks will be used? Existing networks or new networks?
The PacketCableTM Network is a managed, secure IP network deployed over cable TV access network using cable modem headend equipment. Individual local PacketCableTM networks, covering specific geographic areas, are interconnected with IP-based IXC networks or managed backbones of PacketCableTM Member affiliates. Together, this will give PacketCableTM a North American footprint, allowing voice calls originating from and terminating on the PacketCableTM Network without interfacing PSTN networks.
In instances where PSTN connectivity is desired, PSTN connections from local PacketCableTM network can be accomplished with PSTN gateways.
On the customer premises side, PacketCableTM subscribers will be able to originate and terminate calls using a standard 2500 telephone station set and/or a multimedia PC that interfaces directly with the PacketCableTM IP network.
2500 telephone station sets or multimedia PCs connected directly to PacketCableTM IP network are edge devices known as clients. They are controlled by Call Management Servers that reside on the PacketCableTM IP network using PacketCableTM Signaling Protocols.
3.2 - What type of infrastructure is used ?
Infrastructure used for PacketCableTM Network at the network transport layer include cable TV access network, IP-based IXC networks, IP over ATM or IP over Sonet backbone networks.
PSTN networks are also used if PSTN connectivity is necessary.
3.3 - How are mobile and fixed switched networks used to provide IP telephony?
Fixed switched networks are used if economic reasons justify routing calls from IP based networks to PSTN network through PSTN gateways.
3.4 -Which network components are required to offer Internet telephony to the general public, and to businesses ?
Using PacketCableTM Network to offer Internet Telephony to the general public, network components such as embedded clients and cable modems and Ethernet cards (for a PC) are necessary on the customer premises side.
On the PacketCableTM Network, cable headend equipment, call management servers, PSTN gateways etc. are necessary.
3.5 - What is the future of Voice over IP ? substitution of existing networks, integration into current networks?
In the long run, Voice over IP may replace existing PSTN network. In the short to medium term, Voice over IP is a substitute or alternative to PSTN telephone.
4.1 - Is a new generation of telephone terminals, adapters, equipment and specific software required for the provision of Internet telephony services?
Standard 2500 telephone station sets can be used as terminal devices. These devices need to be connected to cable modems with embedded client. No new terminal equipment is required in order to enable VOIP telephony.
4.2 - Is this equipment proprietary or can it be used with all networks and services?
Under the PacketCableTM specifications in North America, the equipment in the headend and PacketCableTM back-office network are specified to be compatible with the DOSCIS specifications. In addition, Com21 plans to make its proprietary cable modem access equipment inter-operate with PacketCableTM specifications based back-office network equipment.
4.3 - Which technical specifications and standards are attached to this equipment? Are they available? Are they stable enough to meet interoperability and quality of service requirements?
PacketCableTM specifications in North America determine the specifications for this equipment. They are not available currently. General availability for PacketCableTM specifications is expected in the middle of 1999. Stability, interoperability and quality of service are yet to be seen.
Other standards will also emerge for VOIP telephony – IETF MEGACO and ITU H.GCP for example. As those standards become stable, vendors will evaluate their applicability for deployment in broadband cable access networks.
4.4 - What are the requirements in terms of interoperability, quality of service, connection, and accessibility with the switched telephone network?
Interoperability, quality of service, connection and accessibility with the switched telephone network are determined by PSTN gateways.
5.1 - Which value chain corresponds to each service offering ? What impact does it have on the cost of the final service ? How will it develop ?
All services mentioned use the same IP transport infrastructure. Because the current expansion in the underlying data-carrying capacity in this IP global infrastructure to handle higher levels of data traffic, incremental requirements for VoIP traffic will mean only marginal increase in infrastructure costs. The cost of the final service will principally be determined by the cost of the consumer terminal device. This may mean reduced revenues for the telephone-only service providers, with a shift to operators who provide voice and data.
5.2 - Are the market parties involved in VoIP from the telecommunications market or from related markets? What is the added value of each of these players in the value chain?
Much of the technical innovation is coming from new market players. In the long run, although much innovation occurs in new market entrants, large telecommunications parties will eventually control markets as large-scale support and operational systems are required to support new VoIP technology. Nevertheless, there will be a shift in market share from mainstream telecommunications suppliers to mainstream data communications players because of their expertise in IP technology and strength in the core Internet infrastructure.
5.3 - Is there a compensation or settlement mechanism between the various players? How could this mechanism best be described?
No settlement system yet exists, although this is a topic being discussed in PacketCable.
5.4 - How is this problem dealt with in other countries ?
As an equipment vendor, Com21 has no specific knowledge in this area.
5.5 - At what level would the harmonisation of these mechanisms be useful ?
As an equipment vendor, Com21 has no specific knowledge in this area.
5.6 - Are the mechanisms described here sustainable? What system could be used to replace them, within what timescale?
As an equipment vendor, Com21 has no specific knowledge in this area.
5.7 - What impact could telephony have on Internet economics ?
Current plans for newer Internet backbones call for adequate capacity be able to handle additional telephony traffic. Hence, people have already factored telephony in the infrastructure being built today. The real impact of telephony will be the larger magnitude of customer-premises equipment (CPE) which will drive down the cost of electronics and drive hardware Internet connection costs to extremely low levels.
Question 6 : Cost and Pricing Structure
6.1 - What is the pricing structure ? What criteria is this based on ?
As an equipment vendor, Com21 has no specific knowledge.
6.2 - What is the relationship between the pricing structure and the value chain(s) ?
As an equipment vendor, Com21 has no specific knowledge of service pricing plans.
6.3 - Are prices cost-oriented ?
Today, VoIP pricing typically follow the flat-rate costing model that is common in Internet-based services. As an equipment vendor, Com21 has no specific knowledge of future pricing plans and whether ISPs will be moving to a metered service model.
6.4 - What is current practice in other countries, with regard to the cost and pricing of Internet services?
Most Internet pricing uses the flat-rate or multiple flat-rate service model.
Question 7 : Service Offerings, Marketing
7.1 -Which services could be associated with the Voice over IP offer defined in 1?
VoIP is currently in field trials for local loop bypass. Several service providers have launched commercial operations for long-distance domestic and international bypass. Technology has been developed, but few applications have begun commercial operations for integrated web/computer/telephony services.
7.2 - What is the position of these service offerings in relation to the public telephone service provided over the fixed or mobile network? Are there any restrictions or specific usage conditions ?
Currently VoIP technology is inadequate to compete for general local-loop telephone service. The most successful service is inexpensive long-distance bypass.
7.3 - Do you associate the development of Internet telephony services with a)the development of other telecommunications services ? b) increased ease of usage ? c) progress in terminal equipment?
Currently, the most active VoIP work is being done to provide competitive local loop over cable in competition with the incumbent local service provider.
7.4 - How are Voice over IP services marketed?
VoIP services for long-distance bypass is marketed as lower-quality, very inexpensive long distance service.
7.5 - What developments, in terms of services and the corresponding offers, could result from the introduction and general use of a) resource reservation protocols? b) the IPV6 protocol?
Work in Packetcable could result in improvements in RSVP-type protocols to provide QoS controls for end-to-end cable-based VoIP telephony.
Question 8 : The Market
- -What effects could Internet telephony have on the following voice markets:
a) corporate,
VoIP will likely affect the corporate market early, as corporations are extremely sensitive to cost improvements (that VoIP provides).
b) general public,
Local regulatory issues and poor voice quality will make growth of a public VoIP market slow. A widely available, toll-quality system will not be available for 3 years.
c) national
Depending up the national telecommunications regulatory laws, growth can be rapid, following development of toll-quality VoIP technology.
d) international ?
Although there will be computer-PC and some long-distance bypass, there will likely be regulatory issues with general growth here due to differences in regulatory status of VoIP.
Does VoIP constitute a single market segment or several? What are the main trends of development in the VoIP market ?
There are 2 key markets, at a minimum: (1) long-distance bypass and (2) local loop bypass. Key technical issues are (1) voice compression, (2) low-cost CPE protocols, (3) name/numbering plans, (4) end-to-end quality controls.
8.2 - What is the market for the different offers described in 1 ? Which factors hinder/contribute to growth, are barriers to entry ?
For service providers, VoIP quality needs to improve before a market can be viable. It is possible that regulatory problems will hinder growth. For equipment suppliers, complexity of large-scale gatekeeper and gateway technology limits participation in those markets to large tele/data-communications suppliers. CPE will be driven by function and costs, which will be dominated by early technology leaders and semiconductor vendors.
8.3 - Do you think that subsidies could be applied to the terminals in this market ?
In the cable industry, customer terminal equipment for integrated data/telephony will be still be priced above $300US for 2-4 telephone lines. If these prices are too high for broad consumer markets, subsidies may be required from the service operator.
8.4 -How will the development of Internet telephony compare with the development of all other national and international Internet services ?
VoIP is lagging Internet service growth by 3-5 years. Technology and standards to manage Quality of Service and uniform calling plan mapping are still being developed. Limited trials will begin in 1999, whereas the Internet market exploded in 1994 with the development of easy-to-use browsers.
8.5 - How will consumers benefit ?
Lower telecommunications costs and higher data rates over faster links. Consumers will also benefit from innovative features such as instant provisioning, customer self-provisioning etc.
9.1 - Can "Internet telephony services" be defined, other than in relation to the definition of the public telephone service ?
Yes. Internet telephony services can also be used to provide corporate or internal PBX services which provide PRIVATE telephone, not PUBLIC telephone service. Also, it is possible to provide data-based, non-telephony services that directly replace telephony-based FAX.
Which a) architecture b) offerings (in 1) does the definition of Internet telephony correspond to ?
Internet telephony applies to local and long-distance bypass.
9.2 - Are there any provisions of the posts and telecommunications code that constitute regulatory barriers to the development of the VoIP service as defined above ?
As an equipment vendor, Com21 has no specific knowledge.
9.3 - Thus defined, does the "Internet telephone service" fall within the scope of the public telephone service, as set out in the posts and telecommunications code? Should it contribute to universal service charges?
As an equipment vendor, Com21 has no specific knowledge.
9.4 - Does the " Internet telephone service" require a more specific definition than that given in the posts and telecommunications code ?
Except for the description outlined, Com21 has no specific knowledge of the code.
10.1 - With regard to licensing, what is the position of the various potential players identified in the value chains ?
A royalty free pool is available for implementers of systems compliant with PacketCable specifications.
10.2 - Do these players use new or existing infrastructure ? What is the status of these different infrastructures with regard to the posts and telecommunications code ?
As an equipment vendor, Com21 has no specific comment in this area.
10.3 - Which provisions, from the technical, economic and regulatory clauses of the schedule of conditions attached to public telecommunications operators’ licences may not apply to Internet telephony as it has been defined?
As an equipment vendor, Com21 has no specific comment in this area.
Question 11 : International Context
11.1 - Which provisions should be proposed within European and international fora, to ensure that Internet telephony develops within a framework that is acceptable and beneficial to all users? What form should these provisions take ? Which forum is the most appropriate ?
As an equipment vendor, Com21 has no specific comment in this area.
11.2 -How capable are Europeans of influencing the implementation of such a framework?
As an equipment vendor, Com21 has no specific comment in this area.
12.1 -Does Internet Telephony require specific E.164 numbering resources from the national numbering plan? Is this plan sufficient ?
Yes. PacketCableTM accomodates E.164 numbering.
12.2 - In order to support the development of competition how can the portability of E.164 numbers a) between the various players (telephone operators, Internet access providers) and b) between various domains, be guaranteed ?
As an equipment vendor, Com21 has no specific comment in this area.
12.3 - Is E.164 numbering adapted to Internet Telephony? What alternatives do you suggest?
Yes, PacketCableTM adopts E.164 numbering.
12.4 - What relation can be established between naming and addressing schemes?
As an equipment vendor, Com21 has no specific comment in this area.
12.5 - What criteria apply to the publication of a list of subscribers to an Internet Telephony service ?
As an equipment vendor, Com21 has no specific comment in this area.
12.6 - What architecture and management structures are appropriate for the directories for conversion of E.164- IP addresses ?
As an equipment vendor, Com21 has no specific comment in this area.
13.1 - How is connection established between the different " networks " and different players that may carry Internet telephony traffic?
Although additional protocols are required to manage quality, the interconnection protocols to handle IP voice are no different than IP data. These connections use standard IP routing, management, and naming protocols.
What type of traffic can be identified, a) according to the origin (purposely-built IP, standard terminal, etc.), b) type, etc. ? Is IP voice traffic specifically identifiable ?
It is likely that adequate information will be contained in VoIP protocols to allow identification of a voice call. Such protocols identify the sender of the IP packets but may not identify the "type" of terminal. It is possible to obtain the Ethernet MAC address, which also identifies vendor, with IP address resolution protocols.
13.2 - What interfaces are used in this interconnection ? Are they proprietary, standardised ? Is specific equipment used for this connection ?Who owns it ?
Currently standards exist to handle computer-to-computer VoIP, e.g. H.323. Additional specifications are being developed for voice-over-cable to define each system-to-system interface in the PacketCable project, managed by CableLabs. These specifications utilise the media stream encoding standardised by H.323, but adopt a different protocol for managing call signaling – SGCP. SGCP is the basis for a protocol called MGCP which is currently one of the protocols submitted for potential standardisation by the IETF MEGACO working group.
13.3 - Which mechanisms enable distribution of the associated costs ?
Each router hop in the IP network can independently manage traffic throughput, priorities, and resource allocation. It is possible that associated costs can be distribbuted by IP route and data throughput. It may make sense to map costs to the number of packets in the VoIP call rather than absolute length of call, because costs are directly associated with number of packets, not number of seconds.
14.1 - Universal Service: What is the relation between Internet telephony and universal service? Should a contribution be required from each category of players ?What contributions should be expected from each category of players ?
As an equipment vendor, Com21 has no specific comment in this area.
14.2 - Emergency Calls: How can the carriage of emergency calls be guaranteed ? Which players will be responsible for them ?What will they cost ?
As an equipment vendor, Com21 has no specific comment in this area.
14.3 - Confidentiality and Neutrality: How will services such as calling line identification, call restriction, malicious call identification be provided, for each of the service offerings ? Will there be special arrangements for these services ? Are there standards? What guarantees of confidentiality of conveyed calls is there ?
As an equipment vendor, Com21 has no specific comment on specific system service implementations. However VoIP equipment will support CLASS functions, if provided by central office equipment.
14.4 - Call Confidentiality: How, for each offering, can legal interception be guaranteed, as required by the law of 10 July 1991? By which player, or in which part of the chain ?
As an equipment vendor, Com21 has no specific comment in this area. Specific VoIP services can be identified and intercepted, but embedded computer-to-computer VoIP data streams may not be detectable and intercepted. In addition, computer-to-computer voice traffic may also be additionally encrypted at the higher protocol layers which, although intercepted, by not be decipherable.
14.5 -Geographic location of the subscriber: In a " Computer to Phone " scenario, how can the subscriber be located from the IP address ?
As an equipment vendor, Com21 has no specific comment in this area. However, current PC self-identification mechanisms from Intel and Microsoft have met with great public resistance and are being disabled by those vendors. Without such electronic fingerprinting schemes, it would be extremely difficult to locate a subscriber with certainty because it is easy to ‘spoof" IP addresses.
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