Upgrading the Switch Hardware

Introduction

When upgrading a switch hardware in the ACI fabric, there are multiple scenarios to consider:

  • Scenario 1 - Upgrade the hardware of spine switches.

  • Scenario 2 - Upgrade the hardware of leaf switches without vPC.

  • Scenario 3 - Upgrade the hardware of leaf switches with vPC.

Each scenario has two variations depending on the supported software versions of the old and new switch hardware.

Variation 1 - Old and new switches can run the same ACI software version.

Variation 2 - Old and new switches cannot run the same ACI software versions.

Whenever possible, it is recommended to run the same software version on both old and new switches (Variation 1). Variation 2 is for a specific situation when the old switch hardware is no longer supported by the software versions that support the new switch hardware.

An Example of Variation 2 - Old and new switches cannot run the same ACI software versions

As mentioned above, Variation 2 is for specific situations when the old switch hardware is no longer supported by the software versions that support the new switch hardware.

The most common scenario is when migrating from the first-generation Cisco Nexus 9000 series switches to newer generation Cisco Nexus 9000 series switches. The first-generation switches are no longer supported starting on Cisco ACI switch software 15.0(1) or later releases while some of the newer generation switches are supported only from 15.0(1) or later.


Note

  • The first-generation Cisco Nexus 9000 switches are equipped with Cisco Application Leaf Engine (ALE) ASICs. The product ID of those switches do not contain -EX, -FX or -GX. Examples are N9K-C9372PX, N9K-C9372PX-E and so on.

  • The newer generation Cisco Nexus 9000 Switches are equipped with Cisco Cloud Scale ASICs. The product ID of those switches have the -EX, -FX, -GX or later suffix. Examples are N9K-C93180YC-EX, N9K-C93180YC-FX, N9K-C93180YC-FX3 and so on.

General Guidelines

  • To determine which transceivers, adapters, and cables support this switch, see the Cisco Transceiver Modules Compatibility Information document.

  • To see the transceiver specifications and installation information, see Transceiver Module Installation Guides.

  • Due to potential traffic loss, it is recommended that you perform the hardware replacement during a maintenance window.

  • It is recommended to move any Cisco Application Policy Infrastructure Controllers (APICs) that are connected to the switches that you are replacing to any other switches in the fabric and wait for the Cisco APIC cluster to become "Fully Fit".

  • When the Auto Firmware Update feature is used, make sure to set the Default Firmware Version to your target version. If the node ID is part of an upgrade group, make sure that the upgrade group is set with your target version, or delete the upgrade group. See Auto Firmware Update for details.

  • The number of ports and port types of the new switches must match the old switch that you are replacing. If the number does not match, then you must change the configuration to accommodate the new ports or port types.

Spine Switches

Old and New Switches Cannot Run the Same ACI Software Version

  1. Upgrade the APIC cluster to the software version that can run the new switch hardware.

  2. Upgrade switches that are not to be replaced to the same version as the APIC cluster.

  3. Follow the same procedure as RMA with the existing switch running the old version and the new switch running the new version.

    See "Procedures and verification" in "Troubleshoot ACI Fabric Discovery - Device Replacement" for details.

Leaf Switches with vPC

As documented in Cisco APIC Layer 2 Networking Configuration Guide, mixing a first-generation switch and newer generation switch in the same vPC pair is not supported. However, it is supported temporarily during the migration with a limitation where the secondary vPC switch will keep its vPC legs down.

Old and New Switches Cannot Run the Same ACI Software Version

Before you begin

Complete the following steps:

  • The Auto Firmware Update policy must be disabled.

  • Upgrade the Cisco APIC cluster to the 4.2(7v) release if the cluster is running an older release. Also upgrade all the switches to the 14.2(7v) release. Wait for the fabric to converge.

  • Upgrade the Cisco APIC cluster to 5.2(7f) release and wait for the cluster to become "Fully Fit."

  • Upgrade switches that are not to be replaced to 15.2(7f).

  • Ensure that the new switches are preloaded and running the equivalent release as the Cisco APICs, that is 15.2(7f) release. Other than source and target version software releases 4.2(7v)/14.2(7v) and 5.2(7f)/15.2(7f), no other software releases are supported for this migration procedure.


Note

The procedure below is not supported when the minimum software version requirement for the new switches is newer than 15.2(7f). In such a case, you need to remove both of the old switches in the vPC pair at once, and add the new switches in one shot.

Procedure

Step 1

From the Cisco APIC GUI, perform the Remove From Controller operation for the operational secondary vPC switch node.

The Cisco APIC clean reboots the switch. Wait for about 10 minutes for this operation to finish. This action prompts all traffic to use the other first generation switch for data traffic.

Note

 

There will be a loss of traffic for a few seconds for the operational secondary vPC when you perform the Remove From Controller operation.

Step 2

Disconnect the cabling from the first generation switch that you just removed.

Step 3

Uninstall the old switch by reversing the order of the steps in the "Installing the Switch Chassis" section of the switch-specific Hardware Installation Guide

Step 4

Install the new switch by following the steps in the "Installing the Switch Chassis" section of the switch-specific Hardware Installation Guide.

Step 5

Connect the loose cabling that you removed from the old switch to the same ports on the new switch.

Step 6

Register the new second generation switch with the Cisco APIC.

Register the new node with the same node name and node ID. This switch becomes part of the fabric. The Cisco APIC pushes the policies to the new switch and keeps down the vPC legs because there is a mismatch of the generation of switches. At this point, the vPC primary continues to send the data traffic.

Step 7

Before you proceed to Step 8, wait for 10 to 15 minutes for the new switch to download the configurations.

Step 8

From the Cisco APIC GUI, perform the Remove From Controller operation for the vPC primary. The Cisco APIC clean reboots the switch.

Wait for about 10 minutes for this operation to finish. The vPC leg on the new switch, which the Cisco APIC kept down earlier, comes up. This action prompts all traffic to move to the new switch. The vPC ports on the new switch can take a few minutes to come up, during which time there will be traffic drops. The duration of traffic drops varies by the scale and flows in the fabric.

Step 9

Disconnect the cabling from the first generation switch.

Step 10

Uninstall the first generation switch as you did in Step 3.

Step 11

Install the second generation switch as you did in Step 4.

Step 12

Connect the loose cabling as you did in Step 5.

Step 13

Register the new second generation switch with the Cisco APIC.

Register the new node with the same node name and node ID. This switch becomes part of the fabric. The Cisco APIC pushes policies to the new switch and the vPC legs comes up and starts passing traffic.