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MX8116n Fabric Expander Modular (FEM) port mapping with external Fabric Switching Engine (FSE)
Fri, 14 Jul 2023 13:16:33 -0000
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The Dell Networking MX8116n FEM acts as an Ethernet repeater, taking signals from an attached compute sled and repeating those signals to the associated lane on the external QSFP56-DD connector. The MX8116n FEM includes two QSFP56-DD interfaces, with each interface providing up to four 100 Gbps connections to the chassis and eight internal 100 GbE server facing ports.
The Dell PowerSwitch Z9432F-ON fixed switch serves as the designated FSE of the MX platform and can support MX chassis deployed with 100 GbE or 25 GbE-based compute sleds. The switch comes equipped with 32 QSFP56-DD ports that provide uplinks, Virtual Link Trunking interconnect (VLTi), and fabric expansion connections.
The goal of this blog is to help you understand port-mapping information about MX8116n FEM, where the module is connected to NIC cards in compute sleds internally on one side and Fabric Switching Engine on the other side on external ports.
Figure 1. Port mapping of dual MX8116n FEM ports to NIC ports
Sled 1 through Sled 4 use Port 2 on the MX8116n, while Sled 5 through Sled 8 use Port 1.
Figure 2. MX8116n internal port mapping
The MX7000 chassis supports up to four MX8116n FEMs in Fabric A and Fabric B. Figure 3 shows one MX8116n FEM module that has two QSFP56-DD 400 GbE ports that can be split into 4x100 GbE to FSE facing ports and 8x100 GbE to facing internal sled NIC ports.
Figure 3. MX7000 chassis front and back physical view with IOMs and sleds port mapping
The MX8116n FEM can operate at 25 GbE and 100 GbE. The 25 GbE solution can support on both dual and quad port NICs, while the 100 GbE solution is supported on dual port NIC only. For the following examples in this blog, the PowerSwitch Z9432F-ON port mapping on 100 GbE dual port NIC using QSFP56-DD cables and 25 GbE dual port and quad port NICs using QSFP56-DD and QSFP28-DD.
The interfaces used on the Z9432F-ON are arbitrary. QSFP56-DD interfaces on the Z9432F-ON can be connected in any order.
Each port group in PowerSwitch Z9432F-ON contains two physical interfaces. The following examples shows the ports of the first port group 1/1/1 that contain interfaces 1/1/1-1/1/2 and the ports of the last port group 1/1/16 that contain interfaces 1/1/31-1/1/32. The port mode for each port interface can be configured in the port group configuration.
Compute sleds with 100 GbE dual port mezzanine cards
The following port group settings are required for 100 GbE dual port mezzanine cards for the Z9432F-ON:
port-group 1/1/1
profile unrestricted
port 1/1/1 mode Eth 100g-4x
port 1/1/2 mode Eth 100g-4x
port-group 1/1/16
profile unrestricted
port 1/1/31 mode Eth 100g-4x
port 1/1/32 mode Eth 100g-4x
Once the port modes are configured and the connections are made, the MX8116n ports auto negotiate to match the port operating mode of the Z9432F-ON interfaces. The internal servers facing ports of the MX8116n auto-negotiate with the mezzanine card port speed of 100 GbE.
Figure 4 shows the interface numbering for each sled and corresponding MX8116n port when using a QSFP56DD based optic or cable:
Figure 4. Z9432F-ON port mapping for 100 GbE solution
Compute sleds with 25 GbE quad port NIC using QSFP56-DD
The following port group settings are required for 25 GbE quad port NIC using QSFP56-DD on the Z9432F-ON:
- For the required 25g-8x port mode operation, the profile must first be set to restricted. This restriction means that the second port interface in the port group can only operate in a restricted mode.
- The restriction on the second port means that it must operate in a 1x mode, making the even ports unsuitable for connections to the MX8116n. Therefore, only the odd ports can be used for connections to the MX8116n.
port-group 1/1/1
profile restricted
port 1/1/1 mode Eth 25g-8x
port 1/1/2 mode Eth 400g-1x
port-group 1/1/16
profile restricted
port 1/1/31 mode Eth 25g-8x
port 1/1/32 mode Eth 400g-1x
Figure 5 shows the interface numbering for each sled and corresponding MX8116n port when using a QSFP56DD based optic or cable:
Figure 5. Z9432F-ON Port mapping for 25 GbE quad port solution for QSFP56DD based optics and cables
Compute sleds with 25 GbE quad port NIC using QSFP28-DD
The 25 GbE quad port NIC solution can use QSF28-DD based optics and cables. The following configuration shows the final state required for 25 GbE quad port NICs:
port-group 1/1/1
profile restricted
port 1/1/1 mode Eth 25g-8x
port 1/1/2 mode Eth 400g-1x
port-group 1/1/16
profile restricted
port 1/1/31 mode Eth 25g-8x
port 1/1/32 mode Eth 400g-1x
Figure 6. Z9432F-ON Port mapping for 25 GbE quad port solution with QSFP28-DD based optics and cables
Compute sleds with 25 GbE dual port NIC using QSFP56-DD
For the required 25g-4x port mode operation, the profile should stay in the default unrestricted setting. Unlike quad port deployments, dual port deployments can use both even and odd ports on the Z9432F-ON.
port-group 1/1/1
profile unrestricted
port 1/1/1 mode Eth 25g-8x
port 1/1/2 mode Eth 400g-1x
port-group 1/1/16
profile unrestricted
port 1/1/31 mode Eth 25g-8x
port 1/1/32 mode Eth 400g-1x
Figure 7 shows the interface numbering for each sled and corresponding MX8116n port when using a QSFP56DD based optic or cable:
Figure 7. Z9432F-ON Port mapping for 25 GbE dual port solution for QSFP56DD based optic or cable
Compute sleds with 25 GbE dual port NIC using QSFP28-DD
The following configuration shows the final state required for 25 GbE dual port mezzanine cards, the profile should stay in the default unrestricted setting:
port-group 1/1/1
profile unrestricted
port 1/1/1 mode Eth 25g-4x
port 1/1/2 mode Eth 400g-1x
port-group 1/1/16
profile unrestricted
port 1/1/31 mode Eth 25g-4x
port 1/1/32 mode Eth 400g-1x
Figure 8. Z9432F-ON Port mapping for 25 GbE dual port solution with QSFP28-DD based optics and cables
References
Dell PowerEdge MX Networking Deployment Guide
Dell Technologies PowerEdge MX 100 GbE Solution with external FSE blog
Dell PowerEdge MX7000 Chassis User Guide