Japanese Carrier Uses RAD Equipment to Guarantee Quality of Service to Its Subsidiaries
ACE-2002 Defines Network Junction Between Carriers

Major Japanese carrier Japan Telecom is focusing on providing its customers with fully integrated international and domestic services. To this end, it has established various subsidiaries to provide a broad range of global, mobile and data communications services. Although the subsidiaries have set up networks of their own, they still, at some point in the network, send traffic over the infrastructure of their parent company. The cellular subsidiary J-Phone, for example, aggregates traffic from several base stations onto a single ATM link and runs it to its base station controller over the ATM infrastructure of Japan Telecom.

Network Junction Unit Assures QoS
Japan Telecom uses RAD’s ACE-2002™ATM device to define the demarcation point between the two networks and to control and manage the traffic flow between them. It allows Japan Telecom to police and shape the traffic coming from J-Phone and provide performance monitoring at the demarcation point and link protection. At the same time, it assures J-Phone that it is receiving the requisite service from Japan Telecom, as stipulated in their service level agreements (SLAs).

Good Experience with ACE
“Japan Telecom selected the ACE-2002 due to its good experience with RAD’s ACE-101™, which guarantees Quality of Service in its leased line ATM service,” says Mr.Hiroshi Maeda of ITFOR, the system integrator for the project. (See the article Japan Telecom Chooses RAD’s ACE-101 NTU for Its MegaLaser Express ATM Leased Line Service) “The ACE-2002 is a high quality product,” says Mr. Masakatsu Nunokawa, Manager of the ATM/Frame Relay Engineering Group at Japan Telecom. “There is no other product that provides ATM protocols such as OAM (operation,administration and management) as well as physical SONET protection in the same device,” he states.

Extra Protection Custom-Made
RAD engineers worked around the clock to implement special features for Japan Telecom within a tight deadline. Specifically, Japan Telecom wanted RAD to develop particular hardware and fiber protection in addition to line redundancy, which automatically switches communication to a backup fiber optic link if the main link fails. Hardware redundancy is carried out by connecting one switch port to two ACE-2002 ports using a Y-cable. In case of a hardware problem in the first module or on part of the fiber link, the
ACE-2002 automatically switches communications to the backup port.
The Y-cables also save Japan Telecom costly ports on the switch. “We experienced good cooperation from RAD engineers, who implemented
all our requests to our satisfaction,” concludes Nunokawa.

ACE-2002 defines a demarcation point between the ATM networks and performs monitoring up to the radio site.