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devel:device_data_model [2007/07/03 14:00] morten |
devel:device_data_model [2007/07/03 19:37] morten added diagrams |
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==== Standalone devices ==== | ==== Standalone devices ==== | ||
- | Standalone devices are the simplest kind. A standalone device consists of a single physical box with few or no options for expansion. This is your typical simple N-port switch. All vendors provide something like this. | + | {{devel:standalone_device.png |Diagram of standalone device}} Standalone devices are the simplest kind. A standalone device consists of a single physical box with few or no options for expansion. This is your typical simple N-port switch. All vendors provide something like this. |
==== Chassis devices ==== | ==== Chassis devices ==== | ||
- | A chassis devices doesn't provide much functionality in itself, it is mostly just a container with slots to fill with expansion cards that make up the important functions of the box. | + | {{devel:chassis_device.png |Diagram of a chassis device}}A chassis devices doesn't provide much functionality in itself, it is mostly just a container with slots to fill with expansion cards that make up the important functions of the box. |
Most large Cisco routers or switches with router functionality are of this kind. | Most large Cisco routers or switches with router functionality are of this kind. | ||
==== Physical stacks ==== | ==== Physical stacks ==== | ||
- | Some vendors provide a way to combine multiple standalone devices into a single functional unit, through the use of a special stacking cable. The stacking cable connects to a stacking port on each device, and functions as a backplane for communication between the devices. Usually, one of the devices in the stack is assigned the role of //commander//; this device takes an IP address, manages the stack as a whole and presents the stack as single device to SNMP management stations. | + | {{devel:stacked_device.png |Diagram of stacked devices}}Some vendors provide a way to combine multiple standalone devices into a single functional unit, through the use of a special stacking cable. The stacking cable connects to a stacking port on each device, and functions as a backplane for communication between the devices. Usually, one of the devices in the stack is assigned the role of //commander//; this device takes an IP address, manages the stack as a whole and presents the stack as single device to SNMP management stations. |
Both 3Com and Cisco are known to have products that are capable of this kind of stacking. | Both 3Com and Cisco are known to have products that are capable of this kind of stacking. | ||
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==== Virtual stacks and clusters ==== | ==== Virtual stacks and clusters ==== | ||
- | Some vendors provide a way to virtually stack multiple standalone devices by connecting them by their regular ethernet ports. Typically, one device in such a stack is assigned the role of //commander//, while the other devices take the role of //members//. The commander will have an IP address and provide management facilities for the stack as a whole. **BUT**, the commander will not present the stack as a single physical unit to the management station. Each device in this stack operates independently of one another; the commander will allow the management station to communicate with each stack member by addressing them with a modified SNMP community string - in essence relaying SNMP communication between the members and the management station. | + | {{devel:virtual_stack.png |Diagram of a virtual stack}}Some vendors provide a way to virtually stack multiple standalone devices by connecting them by their regular ethernet ports. Typically, one device in such a stack is assigned the role of //commander//, while the other devices take the role of //members//. The commander will have an IP address and provide management facilities for the stack as a whole. **BUT**, the commander will not present the stack as a single physical unit to the management station. Each device in this stack operates independently of one another; the commander will allow the management station to communicate with each stack member by addressing them with a modified SNMP community string - in essence relaying SNMP communication between the members and the management station. |
Stack members can optionally also take each their IP address, but will mostly function fine without one. | Stack members can optionally also take each their IP address, but will mostly function fine without one. |