Integrating Shelf Management Solutions into CompactPCI and AdvancedTCA Chassis Designs As today's communications systems strive to achieve higher levels of availability, system management becomes an increasingly important issue. Intelligent solutions require not only hot swappability and reliability in the hardware, but more active monitoring and controlling of the components. With high-powered processors requiring a higher wattage and generating more heat, thermal and power management are also major concerns. For optimum system performance, shelf managers need to be able to play a balancing act with the power, cooling, FRUs (Field Replaceable Units), etc. Carrier grade platforms based on cPCI and ATCA are geared towards High Availability. A shelf manager that is compatible with these open standards will help further this effort. IPMI The PICMG 2.9 specification for system management and the ATCA specification both use IPMB (Intelligent Platform Management Bus) and the IPMI (Intelligent Platform Management Interface) v1.5 specification. The IPMI can be used to monitor the systems physical health characteristics such as voltages, fans, temperature, power supplies and board insertions. The IPMI specification also allows for automatic alerting with remote system shutdown and restarting as well as maintaining an alert remote log. This allows for system administrators to determine the health of the system, finding out if the system is running normally or in a non-operational state. CompactPCI and ATCA both utilize IPMI, but have different shelf management approaches. Requirements of cPCI vs. ATCA CompactPCI, under the PICMG 2.0 R. 3.0 specification, utilizes PICMG 2.9 for shelf management. ATCA, under the PICMG 3.0 specification, has many of its own requirements. The significant differences include: · For cPCI, the available backplane bus voltages are 3.3V, 5V, +/12V. For ATCA, the power source is 48V DC. · For cPCI, the IPMB can have single or dual ports and the bus side of the buffers is powered from IPMB power (+5V) . For ATCA, redundant IPMB's are required and radial or bused IPMB implementations are allowed. The bus side is powered from +3.3V. · For cPCI the pull-up resistors for the off-board I 2C busses are connected to +5V. For ATCA, they are connected to +3.3V. These differences essentially impact the potential to have a single board that works in either type shelf. They can be addressed by automatic detection of a shelf type and adaptation of the board properties. This modular mechanism is described in more detail in the relevant sections below. What We Need in a Shelf Manager The challenge has been to develop an advanced shelf manager that is compatible with both CompactPCI and ATCA systems. To offer the most functionality while adhering to the PICMG 2.0 and 3.0 specifications, there are several important elements and design ideas to keep in mind. The first is thermal management. Using the I2C bus, thermocouple sensors throughout the chassis can identify hot spots. As opposed to simply monitoring the fan speeds, an advanced HA system should actively adjust the fan speeds. This is important, as only certain areas within the chassis may need more airflow. By focusing the fan speed on only areas where it is needed, the system saves its power resources and maximizes efficiency. Another important issue in HA systems is redundancy. A shelf manager can be designed as a stand-alone unit or as dual shelf manager units in a hot swap redundant mode. It should support redundant operation with an automatic switchover, where one shelf manager will be the active one, while the other is a backup unit. Both units monitor each other and either one can activate the switch over if necessary. Another concept is providing for a Telco Alarm. A typical way of implementing it is for the front panel to include a DB15 Telco alarm interface, Telco Alarm LED's, and a Telco Alarm cutoff push button. Using well-known interfaces such as Ethernet 10/100 and RS232 serial interfaces is an advantage. One solution is to provide the RS232 serial interface on the front panel using a mini-DB9 connector. The first Ethernet interface can be routed to a RJ45 connector on the front panel or the backplane and is configurable on the shelf manager with a jumper. The second Ethernet interface is intended for redundancy updates between two shelf managers. Elma IPM Sentry* Shelf Manager Working with Pigeon Point Systems, Elma has developed solutions to integrate advanced shelf management options into their chassis platforms. The Elma IPM SentryT Shelf Manager has been designed to achieve these tasks and meet the needs of shelf managers mentioned above. The shelf manager has been developed for the new PICMG 3.x specifications using the Intelligent Platform Management Interface (IPMI). However, it is also designed to be easily adapted for PICMG 2.0/2.16/2.17 specification families as a Baseboard Management Controller (BMC) interfacing with a dedicated Chassis Management slot. The IPM Sentry shelf manager monitors:
This goes beyond basic monitoring and offers active controlling functions such as adjusting fan speeds, sending out remote alarms, system shutdown, or shutting down individual cards. For example, shelf manager has 4 PWM output signals, which allows it to selectively increase the fan speed. Further, Elma has engineered solutions to control the fans individually in the chassis. This is important as only certain areas with the chassis may generate a hot spot. By focusing the fan speed on only areas where it is needed, the system reduces its power consumption and improves efficiency. A provision for an IEEE standard-based JTAG interface facilitates development, manufacturing, and field service of the unit. It supports SNMP and the software is based on Monterrey Linux. Elma's new CompactPCI and ATCA chassis will have options for integrating the shelf manager. In addition, Bustronic has been developing their line of ATCA, PICMG 2.16, PICMG 2.17, and Low Profile cPCI backplanes to include connections to the IPM Sentry or other shelf management solutions. A shelf manager can be designed with the same base module for cPCI and ATCA, but with a few different components to comply with each of the architecture's specific requirements. However, the form factor will be the same. Form Factor - Compatibility with cPCI and ATCA There are many possibilities for integrating the shelf managers into standard IEEE 1101.10/11 and ATCA configurations. For the IPM Sentry carrier card, we designed it in a standard 3U x 160mm form factor. This is a common size for both 3U and 6U cPCI systems. For pluggability, the shelf manager will use a 2mm HM connector (same as P1 connector in cPCI backplanes) as its interface. The 7 columns by 22 rows in the 2mm HM connector facilitate support of all of the required signals. The module will be fully hot swappable using an IEEE Hot Swap handle and will include the blue LED, etc. An interface board could be used to allow for a pluggable shelf manager without adding a shelf manager connector to the backplane. It can be easily incorporated into the standard cPCI or ATCA chassis in a 3U x 4 HP form factor. Depending where these are placed in the chassis, the interface board might take up a slot or may not. If located within the card cage, the unit will only take up one slot of space and a second module for redundancy can be stacked above or below the main module. This interface board would be cabled to the backplane IPMB signals. The interface board would allow for fan, temperature, voltage, and I²C bus signals, as well as fan and shelf manager presence and healthy signal, to be routed to the shelf manager through various cables. These interface boards would make it easy to run redundant or single shelf managers, depending on the customer's needs. One of Elma's shelf manager solutions was to use a 2mm HM connector plus two 40-pin .1" x .1" post headers, and some power bugs on the interface board. The 2mm HM allows direct plugging to the shelf manager. The two headers allow 80 signals to and from the interface board. The headers would be for the fan connectors, PWM, TACH, voltage & thermal sensor monitoring, fan sense, share lines, and presence signals, etc. Only IPMB signals are connected to go across the backplane. This has been a strong solution as it has allowed a great amount of flexibility for new systems. The second concept is for the shelf manager to directly plug into a backplane, either taking up a slot or plugging into an extended backplane with the interface outside of the card cage. For both PICMG 2.x and PICMG 3.x applications, this connection area would typically be outside of the card cage area to prevent the sacrifice of the number of slots available for use. If the backplane is extended either on the side or above or below the card cage, it would often allow room for connectors for other modules, like pluggable power supplies or fan trays. Again, the shelf manager could come in the same 3U x 160mm form factor with the same connections and component interface as used to plug into the interface board. For example, Elma's 4U ATCA horizontal chassis has this type of implementation where the shelf manager is fixed-plugged into the upper section of the unit outside of the card cage area. Therefore, the 4U unit still offers 5-slots. The ATCA backplane has the 2mm HM connectors on the side, along with RJ45 ports for chassis to chassis cabling. As mentioned previously, ATCA backplanes provide redundant -48V power feeds, while cPCI backplanes provide regulated power (with IPMB_PWR at +5V being the most important in this context) to directly power on-board circuits from centralized power supplies in the shelf. To overcome these differences, the modular carrier board implements the following approaches. When plugged into a cPCI backlane, all the on-board circuits are powered by the +5V inputs from the backplane. For ATCA applications, the modular carrier card provides (as a build time option) a DC/DC converter with -48V redundant input and +5V output voltages. The output voltage is routed back to the backplane connector. An ATCA backplane, in turn, routes the +5V power from the carrier board back to the +5V power inputs of the carrier board (used in a cPCI shelf and otherwise unused in an ATCA shelf). The output of the DC/DC connector is used to distinguish between the cPCI and ATCA shelves. This signal is used to change the IPMB and off-board I 2 C bus electrical properties (reference voltage and pull-up registers) and is available to software as well. Adapter cards can be created for incorporating the shelf manager into cPCI and ATCA chassis. The shelf manager would plug into one side (which has the same form factor in both versions) while the other side plugs into the backplane. Multiple units can be developed so that the backplane side has the form factor to plug into a cPCI chassis or a different one for ATCA. The drawback again here is that the unit would take up a slot of space. However, it would be able to plug into various slots in this format. Another possibility is for the shelf manager to fit as a Rear Transition Module (RTM). However, with the cPCI RTM being 6U x 80mm and ATCA being 8U x 70mm the shelf manager carrier card would have to be configured in one of these form factors. This solution would also eliminate one or more RTM's. Conclusion Through intelligent platform solutions, advanced shelf management can be achieved in formats that are compatible to cPCI and ATCA architecture and specifications. The coming months will bring new solutions in shelf management implementation. Advances like these continue to help build the case for open standard solutions for carrier-grade systems using specifications like CompactPCI, AdvancedTCA, and CompactTCA. * IPM Sentry is a trademark of Pigeon Point Systems. Ram Rajan |
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