Table of Contents

Description

Physical Description

The MGX 8240 shelf is a multi-slot chassis, supporting multiple CES modules and their associated Interface I/O assemblies. The shelf is designed as an integrated unit containing the following:

• 16-slot module cage (15 usable for CES).
  
  
• Single 16-slot mid-plane.
  
  
• Single split slot is designated as the "Common Equipment" slot (this slot is divided into top and bottom).
  
  
• Three Independent Hot-Swappable fan trays (any two of which can adequately cool the fully loaded chassis).
  
  
• Removable air filter.
  
  
• -48 VDC Power Input Module with dual redundant power entries.
  
  
• Individual face plates on each CES Module for Airflow and Electro-Magnetic Interference (EMI) Sealing, as well as Alarm and Connector Identification.
  
  
• Removable Cable Management System.
  
  
• Shelf designed for center mounting only.
  
  
• Shelf designed to be NEBS compliant with the GR-63-CORE and GR-1089-CORE requirements.
  
  

Physical Interfaces

This section describes the types of physical interfaces supported by the
MGX 8240.

Table 2-1 lists the switch physical interfaces under different conditions.

Shelf Specifications

Table 2-2 shows the dimensions of an unmounted MGX 8240 unit.

The shelf is designed to be center-mounted in a standard telecom 23 inch relay rack. Two CES shelves can be mounted in a standard 7-foot configuration.

Module Cage

The CES shelf has a 16-slot module cage. The CES modules are inserted from the front of the chassis and are secured in place using module insertion/extraction levers. The slots are numbered 1 through 16 (from left to right) on the bottom of the module cage.

Slot 1:

• Reserved for common equipment purposes.
  
  
• Divided into two slots (A and B) for the IMC card. These slots are wired in parallel.
  
  
• Provides:
  
  
• • BITS A and B connections for the user.
    
    
  • Ethernet connectivity for remaining 15 slots.
    
    
  • Alarm relay connections for the user.
    
    
  • Termination for both BITS A and B.
    
    

Slots 2 through 16:

• Identical with respect to the CES modules and Interface I/O Mid-plane.
  
  
• Wired for Ethernet connections and have point-to-point connection to slot 1.
  
  
• Coupled to both BITS A and B.
  
  
• Contain alarms relay control signals for four contact closures.
  
  

The Mid-Plane design:

• Eliminates most of the discrete wiring within the shelf.
  
  
• Provides the interconnection for the modules, interface I/O panels, fan tray, and -48 VDC Power Input.
  
  
• Supports hot swapping of modules, Interface I/Os, and fan tray.
  
  
• Has no active circuitry.
  
  

I/O Panels are installed in the rear of the chassis; three types of I/O modules exist:

The I/O modules are inserted and extracted using levers, and locked down with captive hardware. A blank I/O panel is supplied to cover slots that do not contain one of the above modules. (For pinouts, refer to the MGX 8240 Installation Guide.)

Fan Tray

The MGX 8240 incorporates three fan tray assemblies. Each fan tray assembly:

• Is a self-contained module installed from the front of the shelf.
  
  
• Contains three fans.
  
  
• Is hot-swappable for ease of servicing.
  
  
• Has a bi-colored LED to show Ready (green) and Fault (red).
  
  

Any eight of the nine fans are sufficient to cool a fully-loaded chassis. Each fan has a tachometer output. These nine outputs are bused to each of the 15 CES module slots.

During FDOS, the installer select at least one CES module to have the responsibility for monitoring and reporting fan status. All other CES modules have this feature disabled as the default.

Upon detection of any fan failure, the CES performs the following:

• Sets a "major" alarm.
  
  
• Sets the fan tray LED state to Fault on the fan tray containing the failed fan.
  
  

When a fan tray is removed, all three fans on the tray appear to fail. This condition generates fan failure alarms.

Air Intake and Filtering

The shelf is equipped with a removable reusable air filter. Air intake is from the front and from the sides to maximize the intake air volume. Figure 2-3 represents the front and side air intakes.

CES Faceplates

On the chassis, faceplates are installed as follows:

• On each CES module to provide EMI protection and visual indicators as to the status of each module.
  
  
• Unused slots have blank faceplates.
  
  

Power

The DC Input module provides the following features:

• Integral On/Off Switch with Circuit Breaker.
  
  
• EMI Filtering.
  
  
• Terminal Block for A and B Power, A and B Power RTN, and a single Chassis and Logic Ground Terminal.
  
  

Cable Management System

A cable management system is provided with the MGX 8240. It is removable for those customers who wish to use other commercially available systems.

CES Module

The CES module has front panel LED indicators to display module alarm status (see Figure 2-4). All external connectivity to the CES module is through its midplane connector.

Multiple CES modules per chassis can be optionally installed to act as a backup for up to four other CES modules in the chassis. Each CES module has its own temperature sensor for detecting over-temperature conditions, and generates an individual over-temperature "major" alarm.

LED Indications

The LEDs indicate the following:

• "Critical" LED—On a Critical Event, this LED goes from green to red.
  
  
• "Major" LED—On a Major Event, this LED goes from green to red.
  
  
• "Minor" LED—On a Minor Event, this LED goes from green to yellow.
  
  
• "Ready" LED—When the Boot-up Process has successfully completed, this LED goes from red to green.
  
  
• "Redundant Switch Over" LED only applies to Primary CES modules. It indicates that the Backup CES has switched out this primary. To indicate that the module is switched out, this LED goes from green to yellow.
  
  
• The "RS232" connector is for Factory Use only and is an RJ11.
  
  

IMC Card

The Integrated Management Controller (IMC) provides centralized out-of-band management connectivity to the MGX 8240 switch. The IMC can manage (detect and reset) all PSM1 cards in a switch—up to 15. The IMC has the following functions:

• Allows the MGX 8240 to be seen and accessed from the Ethernet as a single entity with a single IP address, instead of as15 separate PSM1 cards or switches. The IMC does Network Address Translation, routing IP traffic to each card within the chassis. The NAT supports customer FTP, Telnet, SNMP, and ICMP traffic.
  
  
• Provides timing to all cards; timing comes from two BITS clocks through the IMC to the cards.
  
  
• Monitors the chassis and communicates results to the management station. It monitors fan trays, temperature, alarm relay, and power input.
  
  
• Monitors IMC card; each of the two cards in the chassis monitors the other.
  
  
• Monitors chassis environment.
  
  
• Sends traps to management station regarding status of IMC card and PSM1 cards.
  
  

Physical Description

The MGX 8240 has 15 full-size slots and 2 half-size slots. An IMC fits into each of the two half-size slots. Each MGX 8240 uses two IMCs, one primary and one backup. Figure 2-6 shows the slot designation for the IMC.

The IMC I/O Panel has an RJ45 Connector for the Shelf Ethernet Interface, an RJ11 Connector for the Shelf RS232 serial interface, pin connectors for the 4 alarm relay contacts, and 2 BITS inputs

The "Redundant Switch Out" LED changes from yellow to green when the IMC becomes primary, and from green to yellow when the IMC becomes secondary.

The "RS232" connector is for factory use only. The "Reset" button, recessed behind the faceplate, does a hard reset of the card.

IMC LEDs

The front of the IMC card has five LEDs: READY, CRITICAL, MAJOR, MINOR, and PRIMARY STATUS. They indicate the following:

• The Critical LED changes from green to red during a Critical Event (that is, one which affects service).
  
  
• The Major LED changes from green to red during a Major Event (that is, one which might affect service).
  
  
• The Minor LED changes from green to yellow during a minor event (that is, one which does not affect service).
  
  
• The Ready LED changes from red to green after the IMC has built its NAT table and has booted up. The system is ready.
  
  
• The Primary Status LED changes from yellow to green when the IMC card becomes primary. The alarm changes from green to yellow when the IMC card becomes secondary.
  
  

The Critical, Major, and Minor alarms reflect the status of all PSM1s in the chassis. The Ready and Primary Status relate only to the IMC itself.

The following alarms will be sent by the IMC card:

• Power (failure of a power input). This is a Major alarm.
  
  
• Backup Failure (IMC card has no backup, or the backup has failed).
  
  

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Note   If a primary card A fails and the backup B takes over, the backup B will become primary and will send the Backup Failure alarm, because its backup (previously primary A) has failed. This is a Major alarm.

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Events

• Switchover (a backup IMC card has become primary)
  
  
• SNMP Error
  
  

Traps

• Cold Start
  
  
• Warm Start
  
  

CES I/O Modules

The CES I/O module provides external connectivity (physical termination) on behalf of a CES module. The CES I/O module normally connects to the CES module across the midplane in the same slot position. If a CES module fails, the I/O module can be switched (controlled by the backup CES module) to route its midplane connections to the backup CES module. The CES I/O module provides the following external connectors:

• Three DS3 (IOM) connectors for channelized DS3 service interfaces, or two OC3 connectors for channelized OC3 (IOO) (second connector used for SONET APS).
  
  
• Two OC3 connectors (second connector used for SONET APS) for ATM trunk.
  
  
• RS232 Async port for CLI.
  
  

Common I/O Module (Release 1)

Release 1 chassis contain a common I/O module, which provides external connectors for all 15 CES modules in the chassis as follows:

• 15 10Base-T ethernet connectors (one for each CES module).
  
  
• Primary BITS timing input (distributed to all 15 CES modules).
  
  
• Secondary BITS timing input (distributed to all 15 CES modules).
  
  
• Alarm relay contacts (normally closed, wired in series for each CES module). This allows each module to independently open the contacts when an alarm is detected.
  
  

The CES module with CES I/O module combined with the Common I/O module forms an independent logical CES module.

The Common I/O Module has been replaced in later releases by the IMC card.