Technical Specifications

As an infrastructure of information highways develops across the country, managers of local, metropolitan and wide-area networks are converging their systems into integrated, managed networks that transparently carry large volumes of data, voice, and video traffic safely and efficiently. Milgo^™ is at the forefront, streamlining and consolidating this information traffic.

The PremNet® high-speed broadband access system utilizes reliable, private fiber, SONET/SDH OC-3c/STM-1, ATM OC-3c/STM-1, or T3 circuits for high-speed backbone transport of LANs, ATM, data, voice, and video traffic between PremNet nodes. It acts as a sophisticated toolkit for constructing flexible, reliable, and easily managed backbone transport systems. These rings of information seamlessly interconnect and manage thousands of sensitive applications on a wide variety of interfaces throughout the world.

Designing networks with the PremNet 5000 eight-slot interface module chassis delivers the optimum solution — providing balance between cost, resilience, and functionality.

PremNet Supports Counter-Rotating Rings for Redundancy

PremNet Broadband System AccessFeatures

• Unilink 100 Mbps rings connected to each other or to SONET/SDH OC-3c/ STM-1 155 Mbps rings for increased bandwidth and performance
• Multimedia data transmission all on the same backbone
• Choice of over 20 interface modules to customize your data, voice, and video transmission types to suit your price and performance needs
• Matrix-switched backplane eliminates configuration constraints, allowing any module to reside in any slot
• Single ring, dual counter-rotating ring or multi-ring network configurations
• The PremNet multi-ring feature allows up to 241 PremNet nodes in a single fiber backbone network
• Provides network-management support
• LEDs that provide node-operating status at a glance
• Software selectable, user-controlled bandwidth allocation in 5 Mbps increments
• Unparalleled network fault tolerance
• Plug-in access for interface modules
• Rack (19 or 23 inch) or tabletop mounting
• Four fans that cool the power supply and link modules

Protocol-Transparent: Native Speeds
To facilitate easy network design and implementation, the PremNet nodes operate exclusively at the ISO physical level, making them completely transparent to all higher-level protocols. As a result, devices on the backbone can appear to be on the same logical network. This greatly extends the normal distances between network devices.

Because you can run multiple data types over the same PremNet backbone, you don't have to create separate networks to support each application type. This greatly consolidates and reduces cabling, saves room in wiring closets, and reduces hardware and maintenance costs. It also makes your network easier to manage, modify and expand. Since PremNet does not impose any special topology or connectivity restrictions, your LAN services can be bridged or routed easily via external equipment.

System-Wide Redundancy
Because of the critical nature of the information being transported across PremNet networks, the PremNet system is designed with full redundancy features that allow it to continue operating in the event of a power, link or node failure.

At the node level, the PremNet backplane is fully redundant, ensuring continued operation in the event that the primary backplane is unavailable. PremNet is the only product in its class to support this feature. PremNet also provides options for redundant power supplies, battery backup, operating logic and fiber links.

At the network level, backbone integrity cannot be compromised. The PremNet counter-rotating ring architecture plus protection switching functionality maintains the backbone's integrity in the event of a node failure or a fiber fault between two nodes. Ring recovery is extremely rapid, typically less than 3/4 second.

To ensure "protection switching," each PremNet node uses two link modules to support counter-rotating rings. In this configuration, the active and standby rings run in opposite directions, automatically healing the ring if it is broken. Connectivity is maintained even during loss of a node or loss of both fiber connections between any two nodes.

Bandwidth Management
Each PremNet chassis acts as a multi-interface distribution point. Information is distributed around the PremNet backbone network through a virtual circuit to any location on the ring. Virtual circuits are defined by the 3 x 3 matrix switch module, which allows bandwidth to be allocated based on the user's requirement via network management control.

The PremNet matrix switch, virtual circuit architecture allows dynamic software control of data paths, even when a new module or node is added to support more users or new applications. You can change the PremNet virtual circuits at any time using simple software commands. You can also redirect data through the network by adding, redefining, or deleting virtual circuits.

Integral matrix-switch technology also eliminates hardware slot dependence. Any module can be placed in any slot in any node.

Dedicated Bandwidth
Time-division multiplexing (TDM) is used to dedicate the bandwidth required for each application on a virtual circuit. This allows the PremNet backbone to provide a secure, transparent data pipe for each application. Dedicated bandwidth allows applications to run at native speed. For example, Ethernet or Token Ring LANs can be connected to remote facilities and yet still operate at full native LAN speeds, as if the users on the LAN were in adjacent offices. This bandwidth is always available, ensuring consistent data delivery. This capability also fully supports time-sensitive applications, including IBM^® 3270 and asynchronous data such as 4-wire voice and one­way and two-way video.

Information Distribution Within a Building

Choice of Network Management Interfaces
The PremNet network can be managed from a variety of network-management platforms: Your existing SNMP-compliant network-management system, Milgo CMS® network management system, or the PremNet local on-board management.

SNMP - PremNet supports a Simple Network Management Protocol (SNMP) agent, which allows graphical management and control of the PremNet chassis and its modules (running under HP OpenView and Tivoli TME 10 NetView for AIX).

Milgo CMS Management System - The CMS management system uses a graphical user interface to centrally manage and control the PremNet network.

Local Console - Text-based local access is available via an asynchronous terminal attached to any PremNet node on the ring. From a single terminal, a network manager can use simple menus to monitor and control port configurations, virtual circuits, and alarms. Remote dial access, using a standard modem, also is supported.

PremNet System Components
Each PremNet node supports a network management module, up to four redundant link modules, up to eight interface modules, two redundant matrix switch modules, and two redundant power supplies.

The common modules (power supply, link, switch and network management) are required for general system operation. These modules can be duplicated to achieve redundancy in the node. To operate properly, a PremNet chassis requires at least one of each of the following modules in a node:

• Power supply module
• One link module, with a maximum of four links per node (T3, SONET/SDH OC-3c/STM-1, ATM OC-3c/STM-1, Unilink LED/Laser)
• Switch module
• Network-management module

Power Supply Modules
There are two types of power supplies available:

AC - The AC power supply module is auto-ranging and automatically senses the voltage input and configures itself to accept voltages between 85 and 265 VAC.

-48 Vdc - The -48 Vdc power supply module accepts input from -42.5 to -60 Vdc. The source is usually a central-office battery or other non-interruptible DC source.

Any combination of power supplies can be used in a node. In redundant configurations, either power supply can be removed from the chassis without interrupting system operation.

Link Modules
The link module is the device located in each PremNet node on the network that enables communication over the ring. PremNet link interface modules include:

• The T3 link module
• The SONET/SDH OC-3c/STM-1 link module (available in a variety of transmission distances and connector types)
• Unilink interface modules (available in a variety of transmission distances and connector types)
• ATM OC-3c/STM-1 link module

Switch Modules
The 30/20 time-slot switch module provides the clock and timing required by the link for data transmission.

To achieve redundancy, install two switch modules in the chassis. Both modules have complete access to both sets of fiber links and all I/O modules.

The 30/20 switch supports up to 30 time slots on each of the three standard PremNet data streams (one from each of two pairs of link modules, and one from the node's interface modules). This switch module can also run in 20-time-slot mode.

The 30/20 switch is a nonblocking time/space switch: time slots within a frame can be reordered within a frame or moved from one data stream to another.

Enhanced Network-Management Modules
The Enhanced Network-Management Module (ENMM) provides complete network management for the PremNet broadband access system. It is SNMP compliant and includes features and capabilities for testing, monitoring, and error reporting.

Interface Modules
The PremNet family includes interface modules for the transparent transport of a wide variety of voice, video, and data traffic. These modules provide the interface for connecting end-user applications to the PremNet ring.

Available interface modules include:

• Ethernet
• Token Ring (4/16 Mbps)
• One-way and Two-way Video
• RS-232
• RS-422
• V.35
• T1/E1
• 4-Wire Voice

Your data, voice, and video network services can be available locally (for example, floor-to-floor within a building) or to users in multiple buildings connected via your PremNet fiber superhighway.

Ring Configurations
PremNet systems can be configured as single node or multinode. A single-node system is a stand-alone chassis with no link modules installed. Multinode systems typically are ring configurations. PremNet ring configurations include single-main ring, dual main ring, and multi-ring topologies.

PremNet Data, Voice, ATM, and Video on a Multi-Ring SONET/SDH OC-3c/STM-1 Backbone
Counter-Rotating Rings
The PremNet counter-rotating ring configuration gives you unparalleled network-fault tolerance. Fiber cuts and node failures are corrected through automatic ring recovery which maintains the ring's integrity.

Multi-Ring Networks
The PremNet backbones' unique multi-ring capability allows you to connect multiple PremNet fiber backbone rings to form a seamless, centrally managed multi-ring network. Multi-ring configurations combine the fault-tolerance capabilities of PremNet's counter-rotating ring with enhanced alarm reporting and fault recovery.

With a multi-ring configuration, you can connect up to 16 nodes per ring and up to 16 rings per network, allowing 241 nodes in a single backbone network. Currently, up to 76 nodes are tested in various multi-ring network configurations.

Multi-Rings:

• Support spanning-tree configurations
• Uses Enhanced Network-Management Module (ENMM) functions to support multi-rings
• Create virtual circuit connections between nodes on different rings

PremNet® 5000 Chassis Broadband Access System
Technical Specifications

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