Logical Device Overview¶
Networks can be designed in AOS before considering hardware vendors by using logical devices (abstractions of physical devices) to specify common device form factors such as number, speeds and roles of each port in one or more rack units (panels). Some of the capabilities of logical devices include:
- Specifying speed and roles for specific ports (For example, the 48th port is always an L3 router edge, or the speed of the 10th port is always 1 Gbps).
- Preparing for port speed transformations (For example, transforming one - 40 GbE port into four - 10 GbE ports)
- Using non-standard port speeds (For example, when using a 1 GbE SFP in a 10 GbE port AOS correctly configures the underlying hardware.)
- Solving for automatic cable map generation that takes into account failure domains on modular systems (For example, a line card).
When hardware devices have been selected, logical devices can be mapped to them with interface maps. Logical devices are also embedded into rack types and rack-based templates.
To access logical devices - from the AOS web interface, navigate to Design /Logical Devices. AOS ships with many predefined logical devices.
To see details - click a logical device name. Logical devices include the following details:
- 64 characters or fewer to identify the logical device
- Port layout based on IP fabric, forwarding engine, line card (slot) or physical layout. A panel contains one or more port groups.
- Port Group
- A group of ports with the same speed and role(s)
- Number of ports
- Number of ports in the port group
- Speed of ports in the port group
- Port is configured to face a superspine device. Applies to 5-stage Clos datacenter fabric only.
- Port is configured to face a spine device.
- Port is configured to face a leaf device.
- Access (Not supported in AOS 3.3.0)
- Port is configured to face an access device.
- L2 Server
- Port is configured to face an L2 server and trunk towards it, with SVI for VLANs, LAG/MLAG for single and dual-attached servers.
- L3 Server
- Port is configured to face an L3 server with routing on the host (BGP).
- External Router
- Port is configured to face a router that is not managed by AOS.
- Port is configured as a peer link between two leaf devices.
- AOS does not attempt to render configuration on a port with the unused role (ex: a dead port)
Access Switches have limited support in AOS version 3.3.0. Please contact Apstra Support to learn more about this feature and the limitations.
Creating Logical Device¶
- From the list view (Design / Logical Devices), click Create Logical Device and enter a name.
- The default panel layout consists of 24 ports (2 rows of 12 ports each). For a different layout, select the number and arrangement of ports to match your requirements by dragging from the bottom-right corner of the layout.
- Select the ports for the port group by dragging to select contiguous ports, or by clicking individual ports. Clicking a port again deselects it.
- Select port speed, and applicable role(s) for the selected ports.
- Click Create Port Group (bottom-middle) to create the port group.
- If unassigned ports remain, repeat the previous two steps until all ports are assigned. For any ports that will not be used, assign them the Unused role.
- To add a panel, click Add Panel (bottom-middle) and repeat the steps as for the first panel.
- Click Create (bottom-right) to create the logical device and return to the list view.
Creating Logical Device - Example¶
Let’s create a logical device with one panel containing one port group with 96 - 10 GbE ports and a second panel containing one port group with 8 - 40 GbE ports.
From the list view (Design / Logical Devices) click Create Logical Device.
A descriptive name is helpful when referring to the logical device later. For our example we entered AOS-96x10-8x40-2, which represents the following characteristics:
- AOS - the operating system using this Logical Device
- 96x10 - one panel with 96 - 10 GbE ports
- 8x40 - one panel with 8 - 40 GbE ports
- 2 - number of panels (rack units)
For the port group in the first panel, drag the bottom-right corner of the port layout to change the default 2x12 configuration to a 3x32 configuration. Leave the number of ports (96) and speed (10 Gbps) as is, and select L2 Server and L3 Server for roles (Connected to).
Click Create Port Group (bottom-middle), then click Add Panel (bottom-middle).
Drag the bottom-right corner of the port layout to change the configuration to 2x4. Leave the number or ports (8) as is, change the speed to 40 Gbps, and connect them to Superspine, Spine, and External Router.
Click Create Port Group, then click Create (bottom-right). The finalized logical device can be seen in the logical device overview above.
Editing Logical Device¶
If a logical device is linked to an interface map, it cannot be changed.
To prevent potentially unintended changes to existing rack types or templates, changes to logical devices do not affect them. If the intent is for a rack type or template to use a modified logical device, then the rack type must be re-imported into the template.
- Either from the list view (Design / Logical Device) or the details view, click the Edit button for the logical device to edit.
- Make your changes.
- To change port group details, access the dialog by clicking its description.
- To add or remove ports from a port group, drag from the bottom-right corner of the port group layout to resize it. If you added ports, enter port speed and role(s).
- To remove a port group, click the delete button (upper-right).
- To add a panel, click Add Panel and enter relevant port group details.
- Click Update (bottom-right) to update it and return to the list view.
Deleting Logical Device¶
If a logical device is linked to an interface map, it cannot be deleted.
- Either from the list view (Design / Logical Devices) or the details view, click the Delete button for the logical device to delete.
- Click Delete Logical Device to delete it from the global catalog and return to the list view.