Black Box Explains... Multiplatform cabling environments.
When using a ServSwitch™ with multiple computer platforms, choosing which peripherals to use to control your diverse group of CPUs can be confusing. Because of the wide variation in connector... more/see it nowtypes and compatibilities, there is a hierarchy to follow when choosing your “user station“ keyboard, monitor, and mouse.
1. If you have at least one Sun® computer in your application, you should use a Sun keyboard and mouse to control your CPUs.
2. If you have a mixture of PCs and Mac® computers, use your PC-style keyboard and mouse to control your CPUs. collapse
Black Box Explains... Multiplatform cabling environments.
When using a ServSwitch™ with multiple computer platforms, choosing which peripherals to use to control your diverse group of CPUs can be confusing. Because of the wide variation in connector types and compatibilities, there is a hierarchy to follow when choosing your “user station“ keyboard, monitor, and mouse.
1. If you have at least one Sun® computer in your application, you should use a Sun keyboard and mouse to control your CPUs.
2. If you have a mixture of PCs and Mac® computers, use your PC-style keyboard and mouse to control your CPUs.
Black Box Explains...Multimode vs. single-mode Fiber.
Multimode, 50- and 62.5-micron cable.
Multimode cable has a large-diameter core and multiple pathways of light. It comes in two core sizes: 50-micron and 62.5-micron.
Multimode fiber optic cable can be... more/see it nowused for most general data and voice fiber applications, such as bringing fiber to the desktop, adding segments to an existing network, and in smaller applications such as alarm systems. Both 50- and 62.5-micron cable feature the same cladding diameter of 125 microns, but 50-micron fiber cable features a smaller core (the light-carrying portion of the fiber).
Although both can be used in the same way, 50-micron cable is recommended for premise applications (backbone, horizontal, and intrabuilding connections) and should be considered for any new construction and installations. Both also use either LED or laser light sources. The big difference between the two is that 50-micron cable provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength.
Single-mode, 8–10-micron cable.
Single-mode cable has a small, 8–10-micron glass core and only one pathway of light. With only a single wavelength of light passing through its core, single-mode cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode does.
Single-mode cable provides 50 times more distance than multimode cable. Consequently, single-mode cable is typically used in long-haul network connections spread out over extended areas, including cable television and campus backbone applications. Telcos use it for connections between switching offices. Single-mode cable also provides higher bandwidth, so you can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber.
Specification comparison:
50-/125-Micron Multimode Fiber
850-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 550 m;
1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 550 m
62.5-/125-Miron Multimode Fiber
850-nm Wavelength:
Bandwidth: 160 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 220 m;
1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 500 m
8–10-Micron Single-Mode Fiber
Premise Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 1.0 dB/km;
Outside Plant Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 0.1 dB/km collapse
Black Box Explains...Multimode vs. single-mode Fiber.
Multimode, 50- and 62.5-micron cable.
Multimode cable has a large-diameter core and multiple pathways of light. It comes in two core sizes: 50-micron and 62.5-micron.
Multimode fiber optic cable can be used for most general data and voice fiber applications, such as bringing fiber to the desktop, adding segments to an existing network, and in smaller applications such as alarm systems. Both 50- and 62.5-micron cable feature the same cladding diameter of 125 microns, but 50-micron fiber cable features a smaller core (the light-carrying portion of the fiber).
Although both can be used in the same way, 50-micron cable is recommended for premise applications (backbone, horizontal, and intrabuilding connections) and should be considered for any new construction and installations. Both also use either LED or laser light sources. The big difference between the two is that 50-micron cable provides longer link lengths and/or higher speeds, particularly in the 850-nm wavelength.
Single-mode, 8–10-micron cable.
Single-mode cable has a small, 8–10-micron glass core and only one pathway of light. With only a single wavelength of light passing through its core, single-mode cable realigns the light toward the center of the core instead of simply bouncing it off the edge of the core as multimode does.
Single-mode cable provides 50 times more distance than multimode cable. Consequently, single-mode cable is typically used in long-haul network connections spread out over extended areas, including cable television and campus backbone applications. Telcos use it for connections between switching offices. Single-mode cable also provides higher bandwidth, so you can use a pair of single-mode fiber strands full-duplex for up to twice the throughput of multimode fiber.
Specification comparison:
50-/125-Micron Multimode Fiber
850-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 550 m;
1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 550 m
62.5-/125-Miron Multimode Fiber
850-nm Wavelength:
Bandwidth: 160 MHz/km;
Attenuation: 3.5 dB/km;
Distance: 220 m;
1300-nm Wavelength:
Bandwidth: 500 MHz/km;
Attenuation: 1.5 dB/km;
Distance: 500 m
8–10-Micron Single-Mode Fiber
Premise Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 1.0 dB/km;
Outside Plant Application:
Wavelength: 1310 nm and 1550 nm;
Attenuation: 0.1 dB/km
Black Box Explains...Ethernet InterRepeater Links
All Ethernet topologies allow a maximum of two IRL (InterRepeater Links) between any two devices. A 10BASE-T Hub counts as a repeater.
For more information, call our FREE Tech Support.
Black Box Explains...Remote Access Servers.
Remote access servers (RASs) are high-level intelligent devices with multiple asynchronous communication ports that connect to modems and provide remote users with dial-in access to a central site network.
You... more/see it nowcan configure your RAS to operate via remote control or remote node access.
Remote control operation enables remote users to send keystroke data and receive screen output from the central site. The actual processing takes place inside the communication server. Remote node access enables the remote user to become a network node and all remote workstations to function as if they were connected locally.
A fixed-port remote access server has a network connection to your LAN and one or more asynchronous RS-232 ports that connect to external modems. It usually comes equipped with 4, 8, or 16 async ports and is easy to install, support, and maintain. These devices are ideal for traveling workers who don’t have a remote office but who need connections to the corporate network for short periods of time.
For configuration flexibility, scalability, and remote wide-area connection options, choose a modular remote-access server that you can change as your network grows. Most modular RASs accept a variety of modules, including:
• High-density async RS-232 modules that connect to external modems or ISDN terminal adapters. These modules typically have eight or more ports.
• High-density modem modules that usually incorporate eight modems on a single card, enabling you to consolidate equipment costs, increase reliability, and simplify management.
• Digital modules that enable you to make direct connections to high-speed digital lines. Instead of using multiple dialup lines, you can use these devices to bring a single high-speed digital phone line—known as a channelized T1— to your equipment.
The best way to determine what type of RAS you need—or whether you need a router or a RAS—is to identify what remote solution will meet your connectivity requirements. If you’re not sure what you need, contact our FREE Tech Support. collapse
Black Box Explains...Remote Access Servers.
Remote access servers (RASs) are high-level intelligent devices with multiple asynchronous communication ports that connect to modems and provide remote users with dial-in access to a central site network.
You can configure your RAS to operate via remote control or remote node access.
Remote control operation enables remote users to send keystroke data and receive screen output from the central site. The actual processing takes place inside the communication server. Remote node access enables the remote user to become a network node and all remote workstations to function as if they were connected locally.
A fixed-port remote access server has a network connection to your LAN and one or more asynchronous RS-232 ports that connect to external modems. It usually comes equipped with 4, 8, or 16 async ports and is easy to install, support, and maintain. These devices are ideal for traveling workers who don’t have a remote office but who need connections to the corporate network for short periods of time.
For configuration flexibility, scalability, and remote wide-area connection options, choose a modular remote-access server that you can change as your network grows. Most modular RASs accept a variety of modules, including:
• High-density async RS-232 modules that connect to external modems or ISDN terminal adapters. These modules typically have eight or more ports.
• High-density modem modules that usually incorporate eight modems on a single card, enabling you to consolidate equipment costs, increase reliability, and simplify management.
• Digital modules that enable you to make direct connections to high-speed digital lines. Instead of using multiple dialup lines, you can use these devices to bring a single high-speed digital phone line—known as a channelized T1— to your equipment.
The best way to determine what type of RAS you need—or whether you need a router or a RAS—is to identify what remote solution will meet your connectivity requirements. If you’re not sure what you need, contact our FREE Tech Support.
Black Box Explains... Fibre Channel Technology.
What is Fibre Channel?
Fibre Channel is a set of communication standards designed to provide high-speed data transfer over a duplex, serial interface. It’s an open standard that supports multiple protocols... more/see it nowincluding higher-level protocols, such as FDDI, SCSI, HIPPI, and IPI, to manage data transfer.
Although it operates at a range of 133 Mbps to 4 Gbps, Fibre Channel is most commonly used at speeds of 1 or 2 Gbps. A working standards group recently announced that 10-Gbps speeds are expected in soon.
Why is it called Fibre Channel?
Originally, Fibre Channel was designed to support only fiber. When copper was added, the International Standards Organization (ISO) task force changed the spelling of fiber to fibre instead of renaming the technology.
Fibre Channel history.
Fibre Channel was first developed in 1988, and the American National Standards Institute (ANSI) formed a committee in 1989. To ensure interoperability, IBM®, Hewlett-Packard®, and Sun Microsystems® formed the FCSI (Fibre Channel Systems Initiative), a temporary organization, in 1992. FCSI later dissolved, and development was handed over to the FCA (Fibre Channel Association) in 1994. ANSI accepted Fibre Channel as a standard in 1994.
The best of both worlds.
This hardware-based standard combines the best of both channel and network communication methods into one I/O interface. It takes advantage of hardware-intensive, quicker point-to-point channel links that offer low overhead, such as SCSI bus technology, as well as the broad connectivity and long-distance benefits of software-intensive network technology.
Where Fibre Channel is used.
Fibre Channel is used to transfer large amounts of data quickly between supercomputers, mainframes, workstations, desktop computers, storage devices, displays, and other peripherals.
Fibre Channel offers reliability, scalability, congestion-free data flow, Gigabit bandwidth, compatibility with multiple topologies and protocols, flow control, self management, hot pluggability, speed, cost efficiency, loop resiliency, and distance. This makes it ideal for large data operations such as Internet/intranets, data warehousing, networked storage, integrated audio/video, real-time computing, on-line services, and imaging.
The most popular application for this technology right now is Storage Area Networks (SANs). Independent methods of centralized storage management within a SAN (e.g., RAID, tape backup or library, CD-ROM library) run more efficiently with a Fibre Channel backbone.
Fibre Channel topologies.
Fibre Channel can be connected by three methods. In all cases, the topology of the network is transparent to the attached devices.
Point to point is the simplest topology, which uses simple bidirectional links between two connected devices.
Arbitrated loop is the most common topology and the most complex. It is distributed, connecting up to 126 devices across shared media, and it offers shared bandwidth. Two ports on the loop establish a point-to-point, full-duplex connection through arbitration among all ports.
The cross-point or fabric-switched topology uses 24-bit addressing to connect up to 2 (to the 24th) devices in a cross-point switched configuration. This enables many devices to communicate at the same time and does not require shared media.
Fibre Channel layers.
Fibre Channel protocol is divided into five hierarchical layers: The three bottom layers, FC-0–FC-2, define the physical transmission standard. Layers FC-3 and FC-4 address interfaces with other network protocols.
FC-0: Media and interface layer that defines the physical link.
FC-1: Transmission encode/decode layer. Information is encoded 8 bits at a time into a 10-bit transmission character (8B/10B from IBM).
FC-2: Signaling protocol layer that serves as the transport mechanism performing basic signaling and framing. FC-2 includes the following classes of service:
• Class 1 provides dedicated connections. Intermix is an optional type of Class 1 service in which Class 1 frames are guaranteed a special amount of bandwidth.
• Class 2 is a frame-switched, connectionless service, also known as multiplex. It guarantees delivery and confirms receipt of traffic.
• Class 3 is a one-to-many, connectionless, frame-switched service. It’s similar to Class 2 except it uses buffer-to-buffer flow control and does not confirm frame delivery.
FC-3: Common-services layer that provides common services required for advanced features such as striping, hunt groups, and multicast.
FC-4: Upper layer for protocol mapping of network and channel data transmitting concurrently over the same physical interface.
Fibre Channel media.
Fibre Channel runs at up to 1 Gbps over copper or fiber, but for higher speeds, fiber is required. Copper-wire cable can be video coax, miniature coax, or, most commonly, shielded twisted pair with a DB9 or HSSDC connector. Fiber choices include 62.5- or 50-µm multimode and 7- or 9-µm single-mode fiber, all with an SC connector.
Other Fibre Channel equipment includes disk enclosures, drivers, extenders, hubs, interface converters, host bus adapters, routers, switches, and SCSI bridges. collapse
Black Box Explains... Fibre Channel Technology.
What is Fibre Channel?
Fibre Channel is a set of communication standards designed to provide high-speed data transfer over a duplex, serial interface. It’s an open standard that supports multiple protocols including higher-level protocols, such as FDDI, SCSI, HIPPI, and IPI, to manage data transfer.
Although it operates at a range of 133 Mbps to 4 Gbps, Fibre Channel is most commonly used at speeds of 1 or 2 Gbps. A working standards group recently announced that 10-Gbps speeds are expected in soon.
Why is it called Fibre Channel?
Originally, Fibre Channel was designed to support only fiber. When copper was added, the International Standards Organization (ISO) task force changed the spelling of fiber to fibre instead of renaming the technology.
Fibre Channel history.
Fibre Channel was first developed in 1988, and the American National Standards Institute (ANSI) formed a committee in 1989. To ensure interoperability, IBM®, Hewlett-Packard®, and Sun Microsystems® formed the FCSI (Fibre Channel Systems Initiative), a temporary organization, in 1992. FCSI later dissolved, and development was handed over to the FCA (Fibre Channel Association) in 1994. ANSI accepted Fibre Channel as a standard in 1994.
The best of both worlds.
This hardware-based standard combines the best of both channel and network communication methods into one I/O interface. It takes advantage of hardware-intensive, quicker point-to-point channel links that offer low overhead, such as SCSI bus technology, as well as the broad connectivity and long-distance benefits of software-intensive network technology.
Where Fibre Channel is used.
Fibre Channel is used to transfer large amounts of data quickly between supercomputers, mainframes, workstations, desktop computers, storage devices, displays, and other peripherals.
Fibre Channel offers reliability, scalability, congestion-free data flow, Gigabit bandwidth, compatibility with multiple topologies and protocols, flow control, self management, hot pluggability, speed, cost efficiency, loop resiliency, and distance. This makes it ideal for large data operations such as Internet/intranets, data warehousing, networked storage, integrated audio/video, real-time computing, on-line services, and imaging.
The most popular application for this technology right now is Storage Area Networks (SANs). Independent methods of centralized storage management within a SAN (e.g., RAID, tape backup or library, CD-ROM library) run more efficiently with a Fibre Channel backbone.
Fibre Channel topologies.
Fibre Channel can be connected by three methods. In all cases, the topology of the network is transparent to the attached devices.
Point to point is the simplest topology, which uses simple bidirectional links between two connected devices.
Arbitrated loop is the most common topology and the most complex. It is distributed, connecting up to 126 devices across shared media, and it offers shared bandwidth. Two ports on the loop establish a point-to-point, full-duplex connection through arbitration among all ports.
The cross-point or fabric-switched topology uses 24-bit addressing to connect up to 2 (to the 24th) devices in a cross-point switched configuration. This enables many devices to communicate at the same time and does not require shared media.
Fibre Channel layers.
Fibre Channel protocol is divided into five hierarchical layers: The three bottom layers, FC-0–FC-2, define the physical transmission standard. Layers FC-3 and FC-4 address interfaces with other network protocols.
FC-0: Media and interface layer that defines the physical link.
FC-1: Transmission encode/decode layer. Information is encoded 8 bits at a time into a 10-bit transmission character (8B/10B from IBM).
FC-2: Signaling protocol layer that serves as the transport mechanism performing basic signaling and framing. FC-2 includes the following classes of service:
• Class 1 provides dedicated connections. Intermix is an optional type of Class 1 service in which Class 1 frames are guaranteed a special amount of bandwidth.
• Class 2 is a frame-switched, connectionless service, also known as multiplex. It guarantees delivery and confirms receipt of traffic.
• Class 3 is a one-to-many, connectionless, frame-switched service. It’s similar to Class 2 except it uses buffer-to-buffer flow control and does not confirm frame delivery.
FC-3: Common-services layer that provides common services required for advanced features such as striping, hunt groups, and multicast.
FC-4: Upper layer for protocol mapping of network and channel data transmitting concurrently over the same physical interface.
Fibre Channel media.
Fibre Channel runs at up to 1 Gbps over copper or fiber, but for higher speeds, fiber is required. Copper-wire cable can be video coax, miniature coax, or, most commonly, shielded twisted pair with a DB9 or HSSDC connector. Fiber choices include 62.5- or 50-µm multimode and 7- or 9-µm single-mode fiber, all with an SC connector.
Other Fibre Channel equipment includes disk enclosures, drivers, extenders, hubs, interface converters, host bus adapters, routers, switches, and SCSI bridges.
Black Box Explains...16850 UART.
The 16850 Universal Asynchronous Receiver/Transmitter (UART) features a 128-byte First In First Out (FIFO) buffer. When implemented with the appropriate onboard drivers and receivers, it enables your onboard serial ports... more/see it nowto achieve sustained data rates of up to 460.8 kbps.
The 16850 UART includes automatic handshaking (RTS/CTS) and automatic RS-485 line control. It also features external clocking for isochronous applications, a performance enhancement not offered by earlier UARTs. collapse
Black Box Explains...16850 UART.
The 16850 Universal Asynchronous Receiver/Transmitter (UART) features a 128-byte First In First Out (FIFO) buffer. When implemented with the appropriate onboard drivers and receivers, it enables your onboard serial ports to achieve sustained data rates of up to 460.8 kbps.
The 16850 UART includes automatic handshaking (RTS/CTS) and automatic RS-485 line control. It also features external clocking for isochronous applications, a performance enhancement not offered by earlier UARTs.
Black Box Explains... Coax cables for ServSwitch products.
What’s the difference between standard and coax cables for ServSwitch™ products? Performance! Coax cables are made with premium-gauge wire, so they can be made in longer lengths. That means you... more/see it nowcan move your workstation up to 100 feet (30.4 m) from your ServSwitch. Plus coax cables have even more shielding to maintain the signal quality and strength you need. If you require high-resolution video or long distances, this is the cable you need! collapse
Black Box Explains... Coax cables for ServSwitch products.
What’s the difference between standard and coax cables for ServSwitch™ products? Performance! Coax cables are made with premium-gauge wire, so they can be made in longer lengths. That means you can move your workstation up to 100 feet (30.4 m) from your ServSwitch. Plus coax cables have even more shielding to maintain the signal quality and strength you need. If you require high-resolution video or long distances, this is the cable you need!
Black Box Explains... SNMP.
SNMP (Simple Network Management Protocol) management is the standard for LAN management, particularly in mission-critical applications. The standard is controlled by the Internet Engineering Task Force (IETF). It was designed... more/see it nowto manage network configuration, performance, faults, accounting, and security.
An SNMP agent must be present at the device level (a router or a hub, for example), either built into the unit or as a proxy agent, and is accessed through a remote terminal. SNMP does not follow a polling protocol. It waits to receive data from the remote device or sends data based on operator commands.
By using one common set of standards, SNMP enables network administrators to manage, monitor, and control their SNMP-compliant network equipment with one management system and from one management station. If a network device goes down, it|s possible to both pinpoint and troubleshoot the problem more efficiently. And a network administrator isn’t limited to equipment from just one vendor when using an SNMP program. collapse
Black Box Explains... SNMP.
SNMP (Simple Network Management Protocol) management is the standard for LAN management, particularly in mission-critical applications. The standard is controlled by the Internet Engineering Task Force (IETF). It was designed to manage network configuration, performance, faults, accounting, and security.
An SNMP agent must be present at the device level (a router or a hub, for example), either built into the unit or as a proxy agent, and is accessed through a remote terminal. SNMP does not follow a polling protocol. It waits to receive data from the remote device or sends data based on operator commands.
By using one common set of standards, SNMP enables network administrators to manage, monitor, and control their SNMP-compliant network equipment with one management system and from one management station. If a network device goes down, it|s possible to both pinpoint and troubleshoot the problem more efficiently. And a network administrator isn’t limited to equipment from just one vendor when using an SNMP program.
Black Box Explains... Smart Serial Interface
Smart Serial is the Cisco router interface. It uses a space-saving 26-pin connector that automatically detects RS-232, RS-449, RS-530, X.21, and V.35 interfaces for both DTE and DCE devices based... more/see it nowon the type of cable used.
Smart Serial connectors can be found on Smart Serial cables and on the dual-serial-port WAN interface cards used in Cisco 2600 and 1720 series routers. The cables feature a Smart Serial connector on one end and a standard cable connector (such as DB25 or V.35) on the other end. The Smart Serial connector attaches to the dual-serial-port WAN interface card.
Each port on the WAN interface card features a Smart Serial connector. Ports can be configured independently to support two different physical interfaces. For example, you can run RS-232 cable to one port and RS-449 cable to the other port using a single WAN interface card.
What if you need to replace that RS-232 cable with V.35 cable? Just plug a Smart Serial–V.35 cable into the port. Because any Smart Serial connector on the WAN interface card attaches to any Smart Serial cable connector, no additional interface or adapter is necessary. Changing the configuration of your network is literally a snap! collapse
Black Box Explains... Smart Serial Interface
Smart Serial is the Cisco router interface. It uses a space-saving 26-pin connector that automatically detects RS-232, RS-449, RS-530, X.21, and V.35 interfaces for both DTE and DCE devices based on the type of cable used.
Smart Serial connectors can be found on Smart Serial cables and on the dual-serial-port WAN interface cards used in Cisco 2600 and 1720 series routers. The cables feature a Smart Serial connector on one end and a standard cable connector (such as DB25 or V.35) on the other end. The Smart Serial connector attaches to the dual-serial-port WAN interface card.
Each port on the WAN interface card features a Smart Serial connector. Ports can be configured independently to support two different physical interfaces. For example, you can run RS-232 cable to one port and RS-449 cable to the other port using a single WAN interface card.
What if you need to replace that RS-232 cable with V.35 cable? Just plug a Smart Serial–V.35 cable into the port. Because any Smart Serial connector on the WAN interface card attaches to any Smart Serial cable connector, no additional interface or adapter is necessary. Changing the configuration of your network is literally a snap!
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.
Compatibility
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 it’s 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 needs—and 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
1000BASE-X refers collectively to the IEEE802.3z standards: 1000BASE-SX, 1000BASE-LX, and 1000BASE-CX.
1000BASE-SX
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. It’s less expensive than 1000BASE-LX, but has a much shorter range of 220 meters over typical 62.5-µm multimode cable.
1000BASE-LX
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.
1000BASE-CX
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...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 standard 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.
Compatibility
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 it’s 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 needs—and 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
1000BASE-X refers collectively to the IEEE802.3z standards: 1000BASE-SX, 1000BASE-LX, and 1000BASE-CX.
1000BASE-SX
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. It’s less expensive than 1000BASE-LX, but has a much shorter range of 220 meters over typical 62.5-µm multimode cable.
1000BASE-LX
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.
1000BASE-CX
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.