FREQUENTLY ASKED QUESTIONS
- What is a Compact PCI Hub?
- What is the advantage of using a Rear Transition Module slot?
- What does the Hub connect to?
- What does Carrier Class mean?
- What does NEBS Compliant mean?
- Where does it get its power?
- How do I turn it ON and OFF?
- Is it hot swappable?
- Can I connect two cPCI hubs together for additional ports?
- What level of reliability does the hub offer?
- Why a Hub? Why not a Switch?
- What is the difference between the Model DS12 and the Model DS12E?
- What is Dual-Speed and how does it work?
- What is a typical application?
What is a Compact PCI Hub?
This is a Hub-on-a-Card for the Compact PCI and VME Chassis. It is designed to eliminate the space traditional rack-mount hubs take up in a system. A cPCI Hub inserts into a rear transition module slot to provide Ethernet connectivity for a cPCI system.
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What is the advantage of using a Rear Transition Module slot?
The rear I/O mounting design provides a hub arrangement where Ethernet cables are kept in the rear of the rack such that walkways are not blocked and other front-insertion modules are easily accessed.
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What does the Hub connect to?
A Front card, a Backplane? To maintain Carrier Class reliability, the cPCI hub has been designed without any interconnection to the Backplane. It is a "standalone card" unit, taking power from an internal 12VDC power source via a small cable (not from pins in the cPCI Backplane). This makes it usable in almost any cPCI or VME system design, by simply mounting it in a 6U rear slot.
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What does "Carrier Class" mean?
To GarrettCom, "Carrier Class" means that the unit (MagnumBlade DS12) is rugged, reliable, low EMI noise, and will pass NEBS testing when in a cPCI system environment. This term has been coined in the telecommunications industry to designate products suitable for the demanding applications in a CO, POP, etc.
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What does "NEBS Compliant" mean?
It means it will pass NEBS testing in a system environment. "NEBS certified", on the other hand, designates an item that has passed NEBS testing as a separate stand-alone unit. Obviously, a hub-on-a-card could not be NEBS tested individually.
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Where does it get its power?
The MagnumBlade has an input power connector on the board, and uses 12VDC power (6.5 watts typical) from inside the Compact PCI chassis.
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How do I turn it ON and OFF?
The hub is ON when power is applied, done by plugging a short power cable into the connector at the bottom of the unit. Removing the power cord turns the unit OFF.
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Is it hot swappable?
Maybe. To service a Magnum Blade DS12, it has to be pulled out of its Rear I/O slot, and the power connector on the DS12's board has to be manually disengaged. (Normally the Ethernet cables are detached before the card is pulled out, stopping the card from functioning). By reversing this procedure, a replacement unit can be installed. Is this "hot-swappable"? It depends on your definition. Since hot-swappable cards normally do not have cables attached, the classical definition would not apply here. Also, hot-swapping in cPCI systems is usually reserved for Front Cards that plug into the Backplane, so the concept would not be expected to apply to Rear I/O modules. Note that designs with redundant Magnum Blade DS12 cards can be implemented, preventing downtime for servicing the DS12 modules.
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Can I connect two cPCI hubs together for additional ports?
Yes. A manual up-link switch on the card (behind RJ-45 port #1, at the top) provides the capability of cascading hubs together in a system without crossover cabling. For example, a cascaded hub may be another DS12 unit or an external Ethernet hub or switch.
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What level of reliability does the hub offer?
The Magnum Blade DS12 has high availability, with over a 30-year MTBF (287,864 hours MTBF @ 40°C calculated per Bellcore standards).
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Why a Hub? Why not a Switch?
The advantages of a hub over switching technology are application dependent. Hubs are preferred where timing is critical because hubs introduce no packet-time delay. Also, all packets are assured of being unconditionally sent to all connected ports. Hubs are robust, simple, have low power consumption, low latency, and will move traffic at full speed between any two ports at a time.
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What is the difference between the Model DS12 and the Model DS12E?
The Model DS12 is a dual-speed auto-sensing 10/100Mb cPCI hub. The Model DS12E is identical except that its speed is fixed at 100Mb/s, no auto-negotiation can occur.
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What is Dual-Speed and how does it work?
Dual Speed means that the twelve RJ-45 ports of the DS12 will function at either 10Mb/s or 100Mb/s. An auto-sensing function is present on the DS12 (not on DS12E) that allows each port to sense a link-whether its operation is to be at 100Mb or 10Mb. If no auto-negotiating device is connected, the default speed is 10Mb. A bridge is included in the Blade hub to interconnect the two traffic domains of the DS12. The bridge filters and selectively forwards packets to allow the necessary packets to cross between 10Mb and 100Mb traffic domains, enabling all users of either the 100 or 10Mb domains to communicate with each other.
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What is a typical application?
A Magnum Blade DS12 hub is typically used to interconnect and manage multiple computers present in a cPCI system. These computers must be present in such applications but also need reliable methods of communication; a hub provides this robust functionality. Additionally, the hub does not connect to the Backplane-another benefit for cPCI system designs because precious bandwidth from the cPCI Backplane will not be taken away by the hub. Having the ability to bring Ethernet connectivity into a cPCI or VME system design without taking up more than one slot significantly improves the design in these computing applications.
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