echnically Advanced Data Network Backup Switches
Abstract: Backup switches allow the users the capability of sharing devices or networks connected to the COMMON port/s among devices or networks connected to the (A, B, C, etc.) lettered or (1, 2, 3, etc.) numbered ports. Network switch designs and capabilities have changed significantly since the dawn of the computer age. This white paper delineates and clarifies some of the capabilities of the network switches on the market today.
Introduction: Network switches have come a long way since they were simply used to select either printer A or B for that report coming from a particular computer. Today's switches can still have simple designs and functions; however, new demands for high-speed capability, high reliability factors, and sophisticated control methods have developed a market for technically advanced network backup switches.
1. Today's Switch Requirements
Let's start at the beginning. The significant number of choices that need to be made to determine the exact switch to meet the user's requirements is an indication of the growing complexity of today's data network backup switches.
Switches are available with any number of positions, including secure off-line positions. The switches can have letters, A, B, C, etc., or numbered positions. Connect and Disconnect, On-Line and Off-Line, Normal and Loopback, and Normal and Crossover positions are also offered.
Switches can be designed to meet space requirements. As an example, a particular switch was developed with a small size and with mounting ears to fit a mobile/motion application. Another switch was designed to be built into a wall for a secure and handy application. Multiple modular units can fit into a rack and can be expandable as required.
Most Rackmount configured switches are designed to fit standard 19" racks. A 1U rackmount switch dimensions are 19" W x 1.75" H x 8.0" D (48.3 x 4.4 x 20.3 cm). A 2U rackmount switch dimensions are 19" W x 3.5" H x 8" D (48.3 x 8.9 x 20.3 cm).
Racks are available to house modular switches. A 19" W x 5.25" H x 7" D (48.3 x 13.3 x 17.8 cm) rack can accommodate multiple switch module chassis of various widths. Filler panels are available to cover empty slots and provide the data center with a neat appearance. Modular switches are ideal for networks that plan expansion over a period of time.
Switches can be built with any connector and with combinations of connectors. An example is a tri-channel A/B switch with both RJ45 and BNC interfaces. Channel 1 allows access to RJ45 devices 1-A or 1-B. Channel 2 allows access to BNC devices 2-A or 2-B. Channel 3 allows access to BNC devices 3-A or 3-B. Fiber optic connectors include ST, SC, LC, ESCON, FC, and others.
Switches can be selected that operate at various speeds. If the switch has RJ45 ports, CAT5, CAT5e, CAT6, CAT6a are options. CAT5 switches allow access to networks rated for 10/100Base-T (up to CAT5). CAT5e switches allow access to networks rated for 1000Base-T Gigabit Networks. CAT6 switches allow access to networks rated for Gigabit Ethernet. CAT6a switches allow access to networks rated for 10/100/1000Base-T.
Switches can be controlled via a push-button or remotely via a number of methods. Switches can switch automatically when they sense a loss of data or receive a trigger signal. Remote control types include RS232 serial, contact closure, IP addressable, and Graphical User Interface (GUI) and any combination of these controls. Automatic control is also available.
Offline switching can be accomplished where the switch can automatically switch to an offline position before switching between ports A and B. A switch can have a secure off-line position where absolutely no data passes through the switch when in the off-line position. This is the ultimate firewall.
The point is that both copper and fiber optic switches can be complex. Let's try to demystify some of the sticking points with further explanations and examples.
2. Flexibility in Switch Controls
Push-button - Many switches offer front-panel push-button for local control. Any person with access to the switch can easily change the switch position. If that's all you need, push-button control is the way to go.
Keylock - A Pass Key can ensures proper authorized usage. The advantage of the keylock is the security of knowing that only the person with the key can change the switch position. The keylock mechanism can be located on the front panel. Removing the key ensures that the switch will remain in the exact position that it was in when it was locked. Pocket the key and rest assured that the switch will continue operating exactly as it was intended.
Remote Control - Now the switching choices are a little more complex, but there are definite advantages. The switch can be controlled remotely in a number of fashions:
RS232 Serial Control - With RS232 serial control, the REMOTE connector accepts RS232 serial data ASCII commands. The remote port may be connected to any standard RS232 port on a computer. The computer, once connected to the remote port, may use any common terminal emulation software to generate RS232 serial data ASCII commands.
Contact Closure - The REMOTE connector accepts Contact Closure signaling for remote control operation. An example of the methodology for contact closure is when the switch detects a transition from open to close and remains closed across pins 2 and 3, the unit will switch to the B position. If the switch detects a transition from closed to open and remains open across pins 2 and 3, the unit will switch to the A position.
IP Addressable - An IP Addressable feature is ideal for critical network alternate-path switching. Remote control and monitoring of the switch position can be from a 10/100 Base-T LAN Ethernet environment. Users can communicate with the switch via TELNET session. The user setup can allow assignment of an IP address for the switch unit.
Graphical User Interface (GUI) - The remote GUI interface allows the user to control the switch remotely with simple point and click operation. Many switches today offer extensive GUI features. To utilize the user-friendly software, the users may simply connect to the switch from a computer with access to the LAN to which the switch port is connected. Simply launch a standard Web browser and type in the appropriate IP address.
Code-Operated - The switch position and lockout can be changed through the data stream on the COMMON port. The switch monitors its COMMON port and its A port for a specified trigger character sequence.
Auto Sensing - With automatic sensing the switch can switch itself based on sensing a loss of carrier (DCD). Some switches have multiple control methods and can also be controlled locally via a front-panel push-button, or the switch can be managed off-site with the Remote option. An Automatic Fallback A/B Switch with Optional Remote Management Port allows a device connected to the COMMON port to connect through to the A port. The unit monitors carrier presence (DCD) signal on the primary line, port A. If carrier is lost, the unit automatically switches to port B. The switch will maintain its connection to port B until carrier presence is again detected on port A. When carrier is detected on port A, the unit will automatically return to the A position. With some switches, the user can override the automatic fallback operation from the front panel and force the unit to operate as an A/B switch.
To sum up flexibility in switch control, today's switches are available with automatic, manual, and remote control systems and with any number of combinations.
3. Redundancy in Network Switches
Redundancy in network switches can mean added reliability. In the first example, the switch uses a redundant system to back itself up. In the second example the switch uses an extra remote port as an additional means of communicating with the switch and an additional power supply port to ensure power is always available to the unit.
Redundant Backup - A particular switch design of interest is a normal/redundant fallback switch that self-configures connectivity based on the devices connected to it. This type switch allows data broadcast, TD of the RS232 interface, from two data origination devices to be channeled to two devices designated as destination devices. The switch will self-configure its connectivity based on the devices connected to it, or the user can override its connection status from a front panel push-button.
This is how the Normal/Redundant switch works. During the Normal mode, the origin device connected to port D1 is connected to port COM1. The device connected to port D2 is connected to port COM2. If the RTS signal is lost from the device connected to D1, the switch changes to Redundant Fallback mode and automatically broadcasts the data from D2 device to both destination devices, COM1 and COM2. Likewise, if the RTS signal is lost from the device connected to the D2, the switch automatically broadcasts the data from the D1 device to both the devices COM1 and COM2. One of the status LED's will be lit steady ON to reflect the connectivity status and signify that the unit is in Automatic operation. To override the Automatic operation, the user simply depresses the front panel push-button and holds it down for 5 seconds and then releases.
Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry
Abstract: Backup switches allow the users the capability of sharing devices or networks connected to the COMMON port/s among devices or networks connected to the (A, B, C, etc.) lettered or (1, 2, 3, etc.) numbered ports. Network switch designs and capabilities have changed significantly since the dawn of the computer age. This white paper delineates and clarifies some of the capabilities of the network switches on the market today.
Introduction: Network switches have come a long way since they were simply used to select either printer A or B for that report coming from a particular computer. Today's switches can still have simple designs and functions; however, new demands for high-speed capability, high reliability factors, and sophisticated control methods have developed a market for technically advanced network backup switches.
1. Today's Switch Requirements
Let's start at the beginning. The significant number of choices that need to be made to determine the exact switch to meet the user's requirements is an indication of the growing complexity of today's data network backup switches.
Switches are available with any number of positions, including secure off-line positions. The switches can have letters, A, B, C, etc., or numbered positions. Connect and Disconnect, On-Line and Off-Line, Normal and Loopback, and Normal and Crossover positions are also offered.
Switches can be designed to meet space requirements. As an example, a particular switch was developed with a small size and with mounting ears to fit a mobile/motion application. Another switch was designed to be built into a wall for a secure and handy application. Multiple modular units can fit into a rack and can be expandable as required.
Most Rackmount configured switches are designed to fit standard 19" racks. A 1U rackmount switch dimensions are 19" W x 1.75" H x 8.0" D (48.3 x 4.4 x 20.3 cm). A 2U rackmount switch dimensions are 19" W x 3.5" H x 8" D (48.3 x 8.9 x 20.3 cm).
Racks are available to house modular switches. A 19" W x 5.25" H x 7" D (48.3 x 13.3 x 17.8 cm) rack can accommodate multiple switch module chassis of various widths. Filler panels are available to cover empty slots and provide the data center with a neat appearance. Modular switches are ideal for networks that plan expansion over a period of time.
Switches can be built with any connector and with combinations of connectors. An example is a tri-channel A/B switch with both RJ45 and BNC interfaces. Channel 1 allows access to RJ45 devices 1-A or 1-B. Channel 2 allows access to BNC devices 2-A or 2-B. Channel 3 allows access to BNC devices 3-A or 3-B. Fiber optic connectors include ST, SC, LC, ESCON, FC, and others.
Switches can be selected that operate at various speeds. If the switch has RJ45 ports, CAT5, CAT5e, CAT6, CAT6a are options. CAT5 switches allow access to networks rated for 10/100Base-T (up to CAT5). CAT5e switches allow access to networks rated for 1000Base-T Gigabit Networks. CAT6 switches allow access to networks rated for Gigabit Ethernet. CAT6a switches allow access to networks rated for 10/100/1000Base-T.
Switches can be controlled via a push-button or remotely via a number of methods. Switches can switch automatically when they sense a loss of data or receive a trigger signal. Remote control types include RS232 serial, contact closure, IP addressable, and Graphical User Interface (GUI) and any combination of these controls. Automatic control is also available.
Offline switching can be accomplished where the switch can automatically switch to an offline position before switching between ports A and B. A switch can have a secure off-line position where absolutely no data passes through the switch when in the off-line position. This is the ultimate firewall.
The point is that both copper and fiber optic switches can be complex. Let's try to demystify some of the sticking points with further explanations and examples.
2. Flexibility in Switch Controls
Push-button - Many switches offer front-panel push-button for local control. Any person with access to the switch can easily change the switch position. If that's all you need, push-button control is the way to go.
Keylock - A Pass Key can ensures proper authorized usage. The advantage of the keylock is the security of knowing that only the person with the key can change the switch position. The keylock mechanism can be located on the front panel. Removing the key ensures that the switch will remain in the exact position that it was in when it was locked. Pocket the key and rest assured that the switch will continue operating exactly as it was intended.
Remote Control - Now the switching choices are a little more complex, but there are definite advantages. The switch can be controlled remotely in a number of fashions:
RS232 Serial Control - With RS232 serial control, the REMOTE connector accepts RS232 serial data ASCII commands. The remote port may be connected to any standard RS232 port on a computer. The computer, once connected to the remote port, may use any common terminal emulation software to generate RS232 serial data ASCII commands.
Contact Closure - The REMOTE connector accepts Contact Closure signaling for remote control operation. An example of the methodology for contact closure is when the switch detects a transition from open to close and remains closed across pins 2 and 3, the unit will switch to the B position. If the switch detects a transition from closed to open and remains open across pins 2 and 3, the unit will switch to the A position.
IP Addressable - An IP Addressable feature is ideal for critical network alternate-path switching. Remote control and monitoring of the switch position can be from a 10/100 Base-T LAN Ethernet environment. Users can communicate with the switch via TELNET session. The user setup can allow assignment of an IP address for the switch unit.
Graphical User Interface (GUI) - The remote GUI interface allows the user to control the switch remotely with simple point and click operation. Many switches today offer extensive GUI features. To utilize the user-friendly software, the users may simply connect to the switch from a computer with access to the LAN to which the switch port is connected. Simply launch a standard Web browser and type in the appropriate IP address.
Code-Operated - The switch position and lockout can be changed through the data stream on the COMMON port. The switch monitors its COMMON port and its A port for a specified trigger character sequence.
Auto Sensing - With automatic sensing the switch can switch itself based on sensing a loss of carrier (DCD). Some switches have multiple control methods and can also be controlled locally via a front-panel push-button, or the switch can be managed off-site with the Remote option. An Automatic Fallback A/B Switch with Optional Remote Management Port allows a device connected to the COMMON port to connect through to the A port. The unit monitors carrier presence (DCD) signal on the primary line, port A. If carrier is lost, the unit automatically switches to port B. The switch will maintain its connection to port B until carrier presence is again detected on port A. When carrier is detected on port A, the unit will automatically return to the A position. With some switches, the user can override the automatic fallback operation from the front panel and force the unit to operate as an A/B switch.
To sum up flexibility in switch control, today's switches are available with automatic, manual, and remote control systems and with any number of combinations.
3. Redundancy in Network Switches
Redundancy in network switches can mean added reliability. In the first example, the switch uses a redundant system to back itself up. In the second example the switch uses an extra remote port as an additional means of communicating with the switch and an additional power supply port to ensure power is always available to the unit.
Redundant Backup - A particular switch design of interest is a normal/redundant fallback switch that self-configures connectivity based on the devices connected to it. This type switch allows data broadcast, TD of the RS232 interface, from two data origination devices to be channeled to two devices designated as destination devices. The switch will self-configure its connectivity based on the devices connected to it, or the user can override its connection status from a front panel push-button.
This is how the Normal/Redundant switch works. During the Normal mode, the origin device connected to port D1 is connected to port COM1. The device connected to port D2 is connected to port COM2. If the RTS signal is lost from the device connected to D1, the switch changes to Redundant Fallback mode and automatically broadcasts the data from D2 device to both destination devices, COM1 and COM2. Likewise, if the RTS signal is lost from the device connected to the D2, the switch automatically broadcasts the data from the D1 device to both the devices COM1 and COM2. One of the status LED's will be lit steady ON to reflect the connectivity status and signify that the unit is in Automatic operation. To override the Automatic operation, the user simply depresses the front panel push-button and holds it down for 5 seconds and then releases.
Tag:Reflectometry, film thickness , ellipsometry, n&k, Optical Critical Dimension, scatterometry
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