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Friday, 26 October 2007 05:13

AT&T Communications

Written by  Marvin Davis
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Introduces a Disaster Plan for Data and Voice,
Providing End to End Disaster Recovery Service

The Growing dependence of companies on their data processing applications increases their vulnerability to unforseen disasters. A company’s survival can be threatened as soon as 48 hours after the loss of its data processing operation.

Awareness of the importance of disaster recovery planning has been increasing among companies, but few have effective contingency plans in place. With their fingers crossed, many firms like to believe “it won’t happen to us.” Business managers must ask themselves what the consequences would be if their companies were no longer able to process information in their key data processing centers.

To insure against the catastrophic effects of a random disaster--and in response to regulatory mandates--information-dependent institutions such as banks and insurance companies are establishing viable, comprehensive and cost-effective disaster recovery contingency plans for their data centers and are subscribing to the services of companies within the disaster recovery industry.

Disaster recovery firms specialize in supplying “mirror image” backup capabilities at an alternative location within a specified time frame. Referred to as “hot sites,” these are strategically located, fully prepared computer facilities with communications capabilities and pre-installed equipment that could backup operations within the first 24 hours of a system failure or disaster. During an emergency, customers redirect their communications lines from their disabled primary host to the reserve computer hardware in the disaster recovery company’s hot site, enabling the restoration of data processing.

Until recently, a weak link in the computer disaster recovery industry was telecommunications. The primary problem was in the cost of leasing dedicated redundant data lines, which would be used only in case of disaster.

Because of its dependence on communications, AT&T has become acutely aware of the importance of disaster recovery for its own internal network, as well as those of its customers. The company committed to identifying solutions to the problem that not only are cost-effective, but also complement the customer’s primary network--whether it is a voice-grade analog private line or high speed digital. AT&T’s introduction of its ACCUNET family of services--specifically ACCUNET T1.5 Service--has demonstrated many solutions that address the needs of the disaster recovery marketplace.

Using ACCUNET RESERVED 1.5 Service for Disaster Recovery

ACCUNET Reserved 1.5 Service has been identified among industry vendors and consultants as providing a viable, cost-effective solution to backing up customers critical data network applications in the event of a disaster.
The reasons for that viability include its pricing, high quality, high capacity digital facilities and ubiquitous access into nodal funtionality consistent with planned ISND architectures.

ACCUNET Reserved 1.5 Service is provided on a reservation basis over a 1.544 mbps digital network employing both terrestrial and satellite technologies between switching nodes. Access is accomplished through dedicated ACCUNET T1.5 Service. This gives customers the flexibility to route their communications over facilities that meet their individual transmission needs.

The predominant use of the ACCUNET Reserved 1.5 network has been for the transmission of audio and video digital signals for video teleconferencing. However, the network also has the capability to support high speed data transmission. ACCUNET Reserved 1.5 Service also includes a broadcast capability, allowing the customer to transmit simultaneously to a number of locations.

The basic disaster recovery configuration using ACCUNET Reserved 1.5 Service requires that the disaster recovery company or customer’s alternate location purchase an ACCUNET T1.5 access line from its site to the node. In the event of a disaster, a customer informs its disaster recovery vendor, AT&T or its alternate site of the emergency. A connection over ACCUNET Reserved 1.5 Service is established to shift traffic from the main site to the alternate site.

The Emergency Restoral Option

The emergency restoral option would allow a customer to cost-effectively reserve digital connectivity over the ACCUNET Reserved 1.5 network with a reduced blockage probability at reservation. In addition, the call would be classified as an open ended reservation, giving the custormer availability for the length of the emergency. This option would be used only for an emergency due to an unforseen disaster (i.e. fire, explosion, flood, sabotage) at a customer’s data processing location: a test or video teleconferencing call cannot be classified as an emergency.
Customers desiring the ability to make an emergency call would pay a minimum usage fee in addition to a higher call set-up charge. The usage sensitive charges would be consistent with a non-emergency call.

Placing an Emergency Reservation Request

When a catastrophe has occurred and the user needs to establish an emergency call, reservation requests should be placed by the customer or the disaster recovery company, when applicable, to the centralized reservation bureau in the same manner as other ACCUNET Reserved 1.5 requests.

After receiving the necessary information (e.g. specific locations, call start time and duration), the reservation attendant enters the request into the database. If a route or series of routes is available for the estimated time frame, the attendant will be able to determine whether the connections are terrestrial or satelite and inform the customer during confirmation.

If an existing route cannot be provided to the emergency subscriber, the reservation attendant will initiate established administrative procedures designed to increase the emergency subscriber’s probability of connection.
When the time arrives, the customer is connected via the ACCUNET Reserved 1.5 network to any other desired location accessing the network. When the customer has completed the call, the connections are automatically removed.

24 Hour Reservation Coverage

Prior to June 6, 1985, the hours for scheduling a reservation were from 8 A.M. to 9 P.M., Monday through Friday, except national holidays. The new reservation schedule is full-time--24 hours a day, seven days a week.

Interconnection with SKYNET Digital Service

ACCUNET Resereved 1.5 Service is AT&T’s premier service for supporting disaster recovery, but other services also are applicable.

SKYNET Digital Service is a satellite-based communications service which uses customer location earth stations to transmit and receive digital data. SKYNET Digital Service will interconnect to ACCUNET Reserved 1.5 Service at 1.544 mbps. The interface between the services will occur at the ACCUNET Reserved 1.5 node. The interconnection strategy will avoid double satelite hops by providing access to ACCUNET Reserved 1.5 at the five earth station locations, which are in the New York, Chicago, San Francisco, Dallas and Atlanta metropolitan areas. Calls will be transmitted from the earth station nodes to their final destination by way of ACCUNET Reserved 1.5 Service at its tariffed rates. The transportability of the customer’s earth stations, generally provided by Vitalink Communications, Inc., enhances AT&T’s ability to provide flexible technological solutions for disaster recovery.

Voice-grade Switching into ACCUNET Reserved 1.5 Service

A basic configuration can be used today for switching voice-grade private line circuits into ACCUNET Reserved 1.5 in an emergency situation. In order to meet the needs of customers who desire a method of diverting their analog circuits to a backup location, customers can order functionality from both the ACCUNET 1.5 and ACCUNET reserved tariffs to do central office multiplexing into the ACCUNET Reserved 1.5 network. The major components are:

  • The M24 feature in Tariff 9 permits the customer to multiplex up to 24 voice-grade channels into a 1.544 mbps signal.
  • Transfer switches on the analog circuit for diverting into the M24 feature.
  • A remotely accessible control unit for operating and releasing the transfer switches.
  • ACCUNET Reserved 1.5 port access for receiving the M24 output for transmission over the usage sensitive network at 1.544 mbps.

Circuit Assurance on ACCUNET reserved 1.5 Service

Circuit assurance within a customer’s network and the ability to have control over their telecommunications capability are the key directions for many of AT&T’s new services. This growing concern for customer control crosses into the ACCUNET Reserved 1.5 world--especially with the evolution of the disaster recovery applicaiton. For the disaster recovery vendor who provides backup solutions to subscribers, a key question in their client’s minds when using the ACCUNET Reserved 1.5 Solution is: “How can I ensure that my dedicated portion is good to the AT&T point-of-presence without depending on AT&T to tell me?” The answer is a loopback capability at the AT&T interface that can be requested by the customer. This will provide customers with the ability to test their dedicated 1.5 local access line to ensure it is working to performance specifications in real-time.

The Disaster Recovery Option

Until recently, two methods have been used most often to provide an emergency routing capability for a large client:

1) A dedicated private network (either terrestrial or satelite) between locations which may be connected in an emergency.
2) The establishment of communication only when an emergency has occurred (generally via portable earth stations), probably through some prior agreement with a communications vendor.

There are inherent disadvantages associated with either of these methods. With a dedicated private network, communications facilities are not being efficiently utilized during normal periods, thereby becoming an expensive solution. With the establishment of emergency communications, there is a risk of untimely installation and incorrect service options, since the back-up system is only put in place during an emergency.


In subscribing to disaster recovery services, companies not only realize the security of alternate data processing capabilities, but they also gain the use of AT&T’s multi-faceted ACCUNET family of services--services evolving and expanding to meet the telecommunications needs of the business community.

This article adapted from Vol. 1 No. 1, p. 6.

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