Black Box Explains...Gigabit Ethernet.
As workstations and servers migrated from ordinary 10-Mbps Ethernet to 100-Mbps speeds, it became clear that even greater speeds were needed. Gigabit Ethernet was developed for an even faster Ethernet... more/see it nowstandard to handle the network traffic generated on the server and backbone level by Fast Ethernet. Gigabit Ethernet delivers an incredible 1000 Mbps (or 1 Gbps), 100 times faster than 10BASE-T. At that speed, Gigabit Ethernet can handle even the traffic generated by campus network backbones. Plus it provides a smooth upgrade path from 10-Mbps Ethernet and 100-Mbps Fast Ethernet at a reasonable cost.
Gigabit Ethernet is a true Ethernet standard. Because it uses the same frame formats and flow control as earlier Ethernet versions, networks readily recognize it, and its compatible with older Ethernet standards. Other high-speed technologies (ATM, for instance) present compatibility problems such as different frame formats or different hardware requirements.
The primary difference between Gigabit Ethernet and earlier implementations of Ethernet is that Gigabit Ethernet almost always runs in full-duplex mode, rather than the half-duplex mode commonly found in 10- and 100-Mbps Ethernet.
One significant feature of Gigabit Ethernet is the improvement to the Carrier Sense Multiple Access with Collision Detection (CSMA/CD) function. In half-duplex mode, all Ethernet speeds use the CSMA/CD access method to resolve contention for shared media. For Gigabit Ethernet, CSMA/CD has been enhanced to maintain the 200-meter (656.1-ft.) collision diameter.
Affordability and adaptability
You can incorporate Gigabit Ethernet into any standard Ethernet network at a reasonable cost without having to invest in additional training, cabling, management tools, or end stations. Because Gigabit Ethernet blends so well with your other Ethernet applications, you have the flexibility to give each Ethernet segment exactly as much speed as it needsand if your needs change, Ethernet is easily adaptable to new network requirements.
Gigabit Ethernet is the ideal high-speed technology to use between 10-/100-Mbps Ethernet switches or for connection to high-speed servers with the assurance of total compatibility with your Ethernet network.
When Gigabit Ethernet first appeared, fiber was crucial to running Gigabit Ethernet effectively. Since then, the IEEE802.3ab standard for Gigabit over Category 5 cable has been approved, enabling short stretches of Gigabit speed over existing copper cable. Today, you have many choices when implementing Gigabit Ethernet:
1000BASE-X refers collectively to the IEEE802.3z standards: 1000BASE-SX, 1000BASE-LX, and 1000BASE-CX.
The S in 1000BASE-SX stands for short. It uses short wavelength lasers, operating in the 770- to 860-nanometer range, to transmit data over multimode fiber. Its less expensive than 1000BASE-LX, but has a much shorter range of 220 meters over typical 62.5-µm multimode cable.
The L stands for long. It uses long wavelength lasers operating in the wavelength range of 1270 to 1355 nanometers to transmit data over single-mode fiber optic cable. 1000BASE-LX supports up to 550 meters over multimode fiber or up to 10 kilometers over single-mode fiber.
The C stands for copper. It operates over special twinax cable at distances of up to 25 meters. This standard never really caught on.
Gigabit over CAT5—1000BASE-TX
The 802.3ab specification, or 1000BASE-TX, enables you to run IEEE-compliant Gigabit Ethernet over copper twisted-pair cable at distances of up to 100 meters of CAT5 or higher cable.
Gigabit Ethernet uses all four twisted pairs within the cable, unlike 10BASE-T and 100BASE-TX, which only use two of the four pairs. It works by transmitting 250 Mbps over each of the four pairs in 4-pair cable. collapse
Black Box Explains...50-micron vs. 62.5-micron fiber optic cable.
As todays networks expand, the demand for more bandwidth and greater distances increases. Gigabit Ethernet and the emerging 10 Gigabit Ethernet are becoming the applications of choice for current... more/see it nowand future networking needs. Thus, there is a renewed interest in 50-micron fiber optic cable.
First used in 1976, 50-micron cable has not experienced the widespread use in North America that 62.5-micron cable has.
To support campus backbones and horizontal runs over 10-Mbps Ethernet, 62.5 fiber, introduced in 1986, was and still is the predominant fiber optic cable because it offers high bandwidth and long distance.
One reason 50-micron cable did not gain widespread use was because of the light source. Both 62.5 and 50-micron fiber cable can use either LED or laser light sources. But in the 1980s and 1990s, LED light sources were common. Since 50-micron cable has a smaller aperture, the lower power of the LED light source caused a reduction in the power budget compared to 62.5-micron cable—thus, the migration to 62.5-micron cable. At that time, laser light sources were not highly developed and were rarely used with 50-micron cable—mostly in research and technological applications.
The cables share many characteristics. Although 50-micron fiber cable features a smaller core, which is the light-carrying portion of the fiber, both 50- and 62.5-micron cable use the same glass cladding diameter of 125 microns. Because they have the same outer diameter, theyre equally strong and are handled in the same way. In addition, both types of cable are included in the TIA/EIA 568-B.3 standards for structured cabling and connectivity.
As with 62.5-micron cable, you can use 50-micron fiber in all types of applications: Ethernet, FDDI, 155-Mbps ATM, Token Ring, Fast Ethernet, and Gigabit Ethernet. It is recommended for all premise applications: backbone, horizontal, and intrabuilding connections, and it should be considered especially for any new construction and installations. IT managers looking at the possibility of 10 Gigabit Ethernet and future scalability will get what they need with 50-micron cable.
The big difference between 50-micron and 62.5-micron cable is in bandwidth. The smaller 50-micron core provides a higher 850-nm bandwidth, making it ideal for inter/intrabuilding connections. 50-micron cable features three times the bandwidth of standard 62.5-micron cable.
At 850-nm, 50-micron cable is rated at 500 MHz/km over 500 meters versus 160 MHz/km for 62.5-micron cable over 220 meters.
Fiber Type: 62.5/125 µm
Minimum Bandwidth (MHz-km): 160/500
Distance at 850 nm: 220 m
Distance at 1310 nm: 500 m
Fiber Type: 50/125 µm
Minimum Bandwidth (MHz-km): 500/500
Distance at 850 nm: 500 m
Distance at 1310 nm: 500 m
As we move towards Gigabit Ethernet, the 850-nm wavelength is gaining importance along with the development of improved laser technology. Today, a lower-cost 850-nm laser, the Vertical-Cavity Surface-Emitting Laser (VCSEL), is becoming more available for networking. This is particularly important because Gigabit Ethernet specifies a laser light source.
Other differences between the two types of cable include distance and speed. The bandwidth an application needs depends on the data transmission rate. Usually, data rates are inversely proportional to distance. As the data rate (MHz) goes up, the distance that rate can be sustained goes down. So a higher fiber bandwidth enables you to transmit at a faster rate or for longer distances. In short, 50-micron cable provides longer link lengths and/or higher speeds in the 850-nm wavelength. For example, the proposed link length for 50-micron cable is 500 meters in contrast with 220 meters for 62.5-micron cable.
Standards now exist that cover the migration of 10-Mbps to 100-Mbps or 1 Gigabit Ethernet at the 850-nm wavelength. The most logical solution for upgrades lies in the connectivity hardware. The easiest way to connect the two types of fiber in a network is through a switch or other networking box. It is not recommended to connect the two types of fiber directly. collapse
Black Box Explains... Single-Mode Fiber Optic Cable
Multimode fiber cable has multiple modes of propagation—that is, several wavelengths of light are normally used in the fiber core. In contrast, single-mode fiber cable has only one mode of... more/see it nowpropagation: a single wavelength of light in the fiber core. This means theres no interference or overlap between the different wavelengths of light to garble your data over long distances like there is with multimode cable.
What does this get you? Distanceup to 50 times more distance than multimode fiber cable. You can also get higher bandwidth. You can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber cable. The actual speed and distance you get will vary with the devices used with the single-mode fiber. collapse
Black Box Explains...Single-strand fiber WDM.
Traditional fiber optic media converters perform a useful function but don’t really reduce the amount of cable needed to send data on a fiber segment. They still require two strands... more/see it nowof glass to send transmit and receive signals for fiber media communications. Wouldn’t it be better to combine these two logical communication paths within one strand?
That’s exactly what single-strand fiber conversion does. It compresses the transmit and receive wavelengths into one single-mode fiber strand.
The conversion is done with Wave-Division Multiplexing (WDM) technology. WDM technology increases the information-carrying capacity of optical fiber by transmitting two signals simultaneously at different wavelengths on the same fiber. The way it usually works is that one unit transmits at 1310 nm and receives at 1550 nm. The other unit transmits at 1550 nm and receives at 1310 nm. The two wavelengths operate independently and don’t interfere with each other. This bidirectional traffic flow effectively converts a single fiber into a pair of “virtual fibers,” each driven independently at different wavelengths.
Although most implementations of WDM on single-strand fiber offer two channels, four-channel versions are just being introduced, and versions offering as many as 10 channels with Gigabit capacity are on the horizon.
WDM on single-strand fiber is most often used for point-to-point links on a long-distance network. It’s also used to increase network capacity or relieve network congestion. collapse
Black Box Explains...KVMoIP access technology.
KVMoIP access technology extends keyboard, video, and mouse (KVM) signals from any computer or server over TCP/IP via a LAN, WAN, or Internet connection. Through this KVM over IP (KVMoIP)... more/see it nowconnection, remote users can access and control a number of servers simultaneously from wherever they are, inside or outside the organization, and anywhere in the world. This technology works in diverse hardware environments and is ideal for managing multilocation data centers and branch offices.
These capabilities translate into real savings for companies having to deal with the proliferation of servers in many offices, particularly for corporations and government agencies required to deliver 24/7 uptime and real-time access to mission-critical servers 365 days a year.
KVMoIP products combine the advantages of remote access software with the benefits of KVM switching technology. Like most KVM switches, KVMoIP products don’t require any software to be loaded on the host computers. They interface directly with the keyboard, monitor, and mouse connectors of the host computer or KVM switch. Circuitry within the KVMoIP device digitizes the incoming video signal and processes it into digital data that is communicated to a viewer program running on a remote client computer over a LAN/WAN or the public Internet.
By addressing network issues from a remote location, you can simply manage issues from your desk, or even save yourself the hassle of traveling to a site in the middle of the night. Use a browser-based connection, even a cell phone or PDA, to reboot or administer a roomful of servers remotely—a real convenience.
KVMoIP products that feature virtual media technology take that convenience further. They enable a remote user to effortlessly move files from a mass storage device—a USB flash drive or CD-ROM drive, for instance—from your location to the computer on which you’re working. Cost savings are realized through reduced downtime and less travel. Plus, in some cases, there‘s no to need replace existing KVM switches with proprietary ones to get a KVMoIP server-control solution.
The Black Box difference
Black Box® ServSwitch™ KVMoIP solutions go further than many other KVMoIP products on the market. They not only enable you to access remote servers, but they do this at the BIOS level—important when you go need to troubleshoot from off-site and don’t want to a dispatch
a technician. Install or recover software applications and install OS patches from your location anywhere in the world. Plus, this BIOS-level control is possible regardless of the server’s brand or model and even works if the operating system is down.
The ServReach™ system is also designed for IT managers seeking global centralized KVM management in a world of mushrooming servers and complexity. This global platform works by consolidating all server access and devices via locally connected KVMoIP devices. All this hardware is then united under a single management appliance or software “umbrella” providing global, yet fully secure, out-of-band control.
The ServReach system works seamlessly with more than 500 variations of analog KVM switches from a multitude of vendors and manufacturers. Because it’s vendor independent, you don’t need to replace your data center’s entire KVM infrastructure. ServReach simply
grafts global centralized KVM management onto the existing server room/data center, aligning with third-party KVM switches already in place. This is done with the ServReach KVMGate (KVIP1000A), an IP gateway device designed to connect to each of the legacy KVM devices to provide global centralized KVM management for a fraction of the cost of competitive systems, ensuring a faster and greater ROI.
If you’re planning on opening or acquiring a new data center or a large number of new servers, the ServReach KVManager (KVMGR) is the answer. It can provide any-by-any access via the ServReach KVMCube (KVIP1001A), a compact, rackmountable, digital matrix IP device that gives fully secure, non-blocking access for any of the users to any of the servers simultaneously.
In addition, the servers controlled by legacy KVM switches via KVMGate can still be managed by the ServReach KVManager at
the same time as the new servers controlled through a gateway. With all the servers under the same KVManager umbrella, data centers can now easily acquire new servers and devices without having to worry about how to incorporate the new infrastructure with the old.
For more information on Black Box KVMoIP solutions, visit blackbox.com/go/ServReach. Find out more by watching a KVMoIP demo and accessing related white papers. collapse
Black Box Explains...Super Dynamic II.
This proprietary processing technology developed by Panasonic® eliminates backlighting problems commonly seen with security camera systems. It gives you clear images regardless of the lighting situation and a dynamic range... more/see it nowthats 64 times greater than that offered by conventional video cameras.
Super Dynamic II accomplishes this by using a double-speed, charge-coupled device (CCD). It takes two pictures in the time
it takes for a conventional CCD to capture one. The first Super Dynamic II picture is a long exposure (1⁄60th of a second) that captures a scenes dark areas; the second is a short exposure (from 1⁄1000th to 1⁄4000th of a second) that captures the scenes bright areas. Super Dynamic II then combines the best quality signals from the two images and outputs them as a Composite analog image.
The technologys enhanced Digital Signal Processing (DSP) circuitry corrects gradation to give you proper black level references so black areas within a scene appear blacknot washed-out shades of gray. It also enables images with high contrast to be seen on the screen.
Whats more, Super Dynamic II technology provides exceptional sensitivity (0.8 lux using an F1.4 lens), enabling the camera to capture vivid details and color even in low-light applications. collapse
Black Box Explains…A terminal server by any other name.
A terminal server (sometimes called a serial server or a console server or a device server) is a hardware device that enables you to connect serial devices across a network.
Terminal... more/see it nowservers acquired their name because they were originally used for long-distance connection of dumb terminals to large mainframe systems such as VAX™. Today, the name terminal server refers to a device that connects any serial device to a network, usually Ethernet. In this day of network-ready devices, terminal servers are not as common as they used to be, but they’re still frequently used for applications such as remote connection of PLCs, sensors, or automatic teller machines.
The primary advantage of terminal servers is that they save you the cost of running separate RS-232 devices. By using a network, you can connect serial devices even over very long distances—as far as your network stretches. It’s even possible to connect serial devices across the Internet. A terminal server connects the remote serial device to the network, and then another terminal server somewhere else on the network connects to the other serial device.
Terminal servers act as virtual serial ports by providing the appropriate connectors for serial data and also by grouping serial data in both directions into Ethernet TCP/IP packets. This conversion enables you to connect serial devices across Ethernet without the need for software changes.
Because terminal servers send data across a network, security is a consideration. If your network is isolated, you can get by with an inexpensive terminal server that has few or no security functions. But if you’re using a terminal server to make network connections across a network that’s also an Internet subnet, you should look for a terminal server that offers extensive security features.
Black Box Explains...Advanced printer switches.
Matrix—A matrix switch is a switch with a keypad for selecting one of many input ports to connect to any one of many output ports.
Port-Contention—A port-contention switch is an... more/see it nowautomatic electronic switch that can be serial or parallel. It has multiple input ports but only one output port. The switch monitors all ports simultaneously. When a port receives data, it prints and all the other ports have to wait.
Scanning—A scanning switch is like a port-contention switch, but it scans ports one at a time to find one thats sending data.
Code-Operated—Code-operated switches receive a code (data string) from a PC or terminal to select a port.
Matrix Code-Operated—This matrix version of the code-operated switch can be an any-port to any-port switch. This means than any port on the switch can attach to any other port or any two or more ports can make a simultaneous link and transfer data. collapse
Black Box Explains...SCSI Ultra2 and LVD (Low-Voltage Differential).
Small Computer Systems Interface (SCSI), pronounced “scuzzy,” has been the dominant technology used to connect computers and high-speed peripherals since the 1980s. SCSI technology is constantly evolving to accommodate increased... more/see it nowbandwidth needs. One of the more recent developments is Ultra2 SCSI.
Because Ultra2 SCSI is backward compatible, it works with all legacy equipment. Ultra2 doubles the possible bandwidth on the bus from 40 to 80 MBps! Just as importantly, Ultra2 supports distances up to 12 meters (39.3 ft.) for a multiple-device configuration. Ultra2 uses Low-voltage Differential (LVD) techniques to transfer data at faster rates with fewer errors. Don’t confuse Ultra2 with LVD. Ultra2 is a data-transfer method; LVD is the signaling technique used to transfer the data.
Cables are very important when designing or upgrading a system to take advantage of Ultra2 SCSI. Cables and connectors must be of high quality and they should come from a reputable manufacturer to prevent crosstalk and minimize signal radiation. BLACK BOX® Ultra2 LVD cables are constructed of the finest-quality components to provide your system with the maximum protection and highest possible data-transfer rates. collapse
Black Box Explains... How Autocross conversion can work for you.
When using media converters with 10BASE-T or 100BASE-TX cable, you may need to connect your converter to a non-hub device such as a PC or printer.
According to IEEE 802.3 Ethernet... more/see it nowstandards, media converters originally needed a specially pinned crossover cable to connect to PCs. The crossover cable matches the devices transmit and receive pins. Now there are media converters that use straight-pinned 10BASE-T patch cable but incorporate an uplink or crossover connection—a switch on the converter thats set to support the PC-to-converter connection. By setting the uplink switch to “cross,” the converters internal mechanism crosses the pins on the RJ-45 connector to simulate a crossover cable.
Autocross conversion eliminates both the need to crosspin cables and set an uplink switch. It adapts to the pin assignment of the twisted-pair cable whether it’s crossed or uncrossed. And because it senses the pin configuration of any cable pinned to Ethernet specifications, it adjusts automatically without user configuration. collapse