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Securing a lifeline for cable telephony

Sun, 02/28/1999 - 7:00pm
Ham Mathews, Director of IP Business Development; and Glen Skrivseth, Technical Marketing Engineer, ADC Telecommunications' Broadband Networks Division

... part II

Residential gateways

Having understood the value of delivering lifeline service to the consumer, MSOs need to evaluate the residential gateway devices used to offer lifeline and other services. The three predominant solutions include cable modems, set-tops and ISUs. Each has their advantages and disadvantages. The following analysis addresses all three methods and compares their ability to support lifeline and additional services yet to be developed.

1. Cable modems.

Status: Currently shipping, this solution delivers high-speed data service over the HFC platform. The objective is to add VoIP capabilities, and comply with Data- Over-Cable Service Interface Specification (DOCSIS) standards.

Location: Cable modems are positioned within the residence near the computer, creating greater cosmetic demands resulting from this prominent location. These devices may be obsolete as data rates increase, additional services are deployed and standards are established.

Purchasing: Cable modems are purchased through retail channels, taking the MSO out of the channel. MSOs needn't worry about inventory, returns and repairs, but do they want to lose control of this segment of the business? Connectivity: The cable modem hooks directly into the computer. There remain two interfaces that need to be addressed for successful implementation. One is the matter of providing power backup in the case of a residential power outage. The other is the integration of existing home telephony service over standard twisted pair. Running video service from the modem to the television and residential changes to in-home wiring could impair signal quality and modem performance.

Installation: The consumer performs installation, often increasing customer service demands on the MSO. Plus, if the consumer moves to a different home, they likely will have to purchase another modem for the new location. Repairs and upgrades: These functions are handled by the consumer through the retail channel, and service is disrupted during the process. Repairs and upgrades, along with powering, prevent the cable modem from successfully offering lifeline service.

Provisioning: Network management should be able to remotely monitor the unit's status and be able to assist in diagnosing service problems. With the modem located past the residential point of presence, this will add to the difficulty in maintaining and managing service. Power: Cable modems draw about 15 to 17 watts, which limits their ability to be line powered via HFC. Some form of battery back-up will need to be developed. Security: Consumers have complete access to the unit. Additionally, modems need to meet indoor electronic requirements.

2. Set-top boxes.

Status: These are currently shipping with VoIP capabilities being added.

Location: Set-top boxes are placed next to the TV, also placing greater demands on the cosmetic appearance of the unit.

Purchasing: Units are bundled with the service provided by the MSO or can be purchased through some retail channels. Set-tops do not currently provide significant capabilities to support additional growth.

Connectivity: These devices face similar connectivity issues to the cable modem in that there is no clean wiring solution between data and voice access.

Installation: Set-tops can be installed by the consumer, but usually require a visit by a service technician. Installation needs to be coordinated with the consumer.

Repair and upgrades: This activity also needs to be coordinated with the consumer. Will disrupt service and make the delivery of lifeline service impossible.

Provisioning: A set-top box does not provide a clean migration path to add telephony lines or act as a gateway to provide multiple computer access to high-speed data capability.

Power: Power consumption is about 25 watts, which also prohibits its ability to be line powered. Some form of local battery back-up will need to be developed.

Security: These devices can be stolen and tampered with by the consumer.

3. Integrated Services Units (ISUs).

Status: ISUs are currently supporting the deployment of lifeline circuit-switched telephony service. Symmetrical data is available (Nx64) up to 512 Kbps or 8 Mbps, depending on the model installed. VoIP and related lifeline capabilities are now being developed in standards committees.

Location: ISUs can be located external or internal to the residence. External units are environmentally-hardened and provide secure access for the service tech with limited access by the consumer. Internal options are also available, which gives the consumer and provider greater installation options. An externally-mounted unit gives the tech greater flexibility in performing installation, service and repair functions.

Purchasing: Owned by the MSO, the ISU physically stays with the delivery of service. It is installed by the MSO and can be populated with additional service growth modules as new services are purchased by consumers. The MSO can install the unit today and provide lifeline circuit-switched telephony and integrated symmetrical data. Then the MSO can retain its investment while VoIP develops and becomes viable for deployment.

Connectivity: The ISU acts as a logical and functional wiring concentration point for coax, twisted pair and future wireless networking. ISUs can take advantage of existing residential wiring, and with minimal additional investment, can network multiple devices within the residence to provide greater gateway functionality.

Installation: This service is performed by the MSO installation technician and can be completed without the consumer being home if the unit it located on the outside of the residence.

Repair and upgrades: These activities can be performed without disrupting other services. A technician can perform repairs/upgrades without coordinating with the consumer. Complete redundancy in the ISU product can significantly decrease the mean time to identify and repair problems. Modular construction makes the fast swapping of components a time-saving advantage. Provisioning: Additional service growth modules can be installed as needed. Incremental services can be provisioned and handled by the host digital terminal (HDT).

Powering: ISUs require less than four watts, making this the only solution that makes economic sense for line powering. Residential powering and battery back-up are also available to give the MSO greater powering options. Security: ISUs are physically mounted either on the outside or inside of the residence. Access is limited and requires special tools. The unit is enclosed in an environmentally-hardened case.

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Table I: Home networking alternatives.

Once requirements for the residential gateway device have been determined, the next mountain to climb is residential networking. Households increasingly have multiple PCs that would benefit from sharing networked resources such as printers and high-speed Internet access. Residential networking requirements include no new wiring; simple installation; low cost; range adequate for the typical home; ability to support high-speed data rates and future growth; and finally, security. There are a variety of networking/wiring challenges MSOs encounter within the residence. Random and unspecified wiring topologies, noise, and varying transmission line characteristics are a few of the obstacles.

Another point to take into account is that the typical residence is wired for two lines. For the existing local service provider to offer more than two lines, they need to physically run additional wires to the home or invest in an alternative digital subscriber line (xDSL) platform with additional customer premises equipment. Delivering service via an ISU allows MSOs to successfully climb all of these networking mountains.

Table 1 addresses some of the home networking alternatives that will be developing in the near future. Once MSOs deliver lifeline service, they need to take advantage of their residential point-of-presence to offer enhanced gateway functionality. The chart presents some of the functionality that will soon be added to modems, set-tops and integrated service units. The point is that the home will be networked. The question then becomes, how do you add this network functionality to a device currently delivering industry convergent services?

Reaching the summit

To reach the peak of telephony in the minds of consumers, MSOs must have a lifeline—literally—to ensure the absolute reliability that is expected when a user picks up the phone. ISUs are proven to be the best residential gateway method for delivering lifeline service because they meet each of the key deployment objectives:

  1. Provide lifeline telephony service (circuit-switched) today with a migration path to VoIP
  2. Allow economical network powering-less than three watts on the NID
  3. Deliver a convergent service mix of voice, video and data
  4. Enable residential networking to share resources such as high-speed Internet access.

ham_mathews@adc.com

glen_skrivseth@adc.com

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