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Smooth Upgrade from SFB to SFB2

Understanding the Smooth Upgrade Process

The MX2000 line of routers support Switch Fabric Board (SFB; model number: MX2000-SFB) and the enhanced Switch Fabric Board (SFB2; model number: MX2000-SFB-S). SFB2 is designed to support higher bandwidth than that provided by SFB on the MX2000 line of routers. For instance, the MX2000 line of routers with SFB support fabric bandwidth of 800 Gbps. However, the MX2000 line of routers with SFB2 can support fabric bandwidth of 1.92 Tbps. A smooth upgrade enables you to upgrade from SFB to SFB2 with minimal traffic impact on the MX2000 line of routers.

Note:

If you have installed the Junos Continuity software package, you cannot perform a smooth upgrade from Switch Fabric Board (SFB) to Enhanced Switch Fabric Board (SFB2) on MX2010 and MX2020 routers.

This topic explains the smooth upgrade process that takes place when you upgrade from Switch Fabric Board (SFB) to enhanced Switch Fabric Board (SFB2) on MX2000 line of routers.

Note:

The MX2000 line of routers support either SFB or SFB2 only. The MX2000 line of routers do not support SFB and SFB2 at the same time. However, during an upgrade from SFB to SFB2, the MX2000 line of routers support both SFB and SFB2 at the same time for the duration of the upgrade. But, you must upgrade all 8 SFBs to 8 SFB2s. You cannot replace 4 SFBs with 4SFB2s and retain the other SFBs.

The process of smooth upgrade from SFB and SFB2 includes the following steps:

  1. Initiating the smooth upgrade process. When you initiate smooth upgrade, the router can support both SFB and SFB2 at the same time.

  2. Performing the smooth upgrade. This step consists of replacing all SFBs with SFB2s.

  3. Terminating the smooth upgrade. When you terminate the smooth upgrade process, the router stops supporting SFB and SFB2 at the same time.

A smooth upgrade provides the following benefits:

  • The smooth upgrade eliminates network downtime during the smooth upgrade window because of 7+1 fabric redundancy. When one SFB is being upgraded to SFB2, the other seven SFBs are available to handle the traffic.

    Note:

    If multiple SFBs are upgraded at the same time, multiple fabric planes are down at any specified time and so traffic is impacted.

  • When multiple fabric boards and planes come online at the same time, you can batch them together and train. This reduces the booting up time and the time taken for the plane to come online.

  • On MX2000 line of routers with SFB, fabric grant bypass is enabled by default. Disabling fabric grant bypass helps control congestion and improves performance. On MX2000 line of routers with SFB, you can disable fabric grant bypass by By default, fabric grant bypass is disabled for all MPCs on MX2000 line of routers when they connect to SFB2. Fabric grant bypass is enabled by default on MPC1 (MX-MPC1-3D), MPC2 (MX-MPC2-3D), and the 16-port 10-Gigabit Ethernet MPC (MPC-3D-16xGE-SFPP). When fabric grant bypass is enabled by default, when those MPCs connect to SFB2, fabric grant bypass continues to be enabled and cannot be disabled.

To quickly access the information you need, click the links in Table 1.

Table 1: Locating the Information You Need to Work on Smooth Upgrade Process

Task You Need to Perform

Where The Information Is Located

Before You begin

Before you Begin the Smooth Upgrade Process

Perform a Smooth Upgrade

Performing a Smooth Upgrade to Enhanced Switch Fabric Board (SFB2) with Minimal Impact on Traffic

Before you Begin the Smooth Upgrade Process

Before you begin the smooth upgrade from Switch Fabric Board (SFB) to enhanced Switch Fabric Board (SFB2), complete the following tasks:

Note:

If you have installed the Junos Continuity software package, you cannot perform a smooth upgrade from Switch Fabric Board (SFB) to Enhanced Switch Fabric Board (SFB2) on MX2010 and MX2020 routers.

  • Prepare the router and install the version of Junos OS Release (16.1R1 or later) that supports the smooth upgrade process. For more information about how to install or upgrade the version of Junos OS Release, see Installing the Software Package on a Device with Redundant Routing Engines (Junos OS).

  • Verify that the Switch Fabric Boards and fabric planes are online and operational. At this time, the line cards are connected to SFB.

  1. To verify that all the switch fabric boards (SFBs) are online and operational, issue the following command:
  2. To verify that all the fabric planes are available and operational, issue the following command:
  3. To verify that the state of the electrical switch fabric links between the Flexible PIC Concentrators (FPCs) and the Switch Fabric Boards (SFBs) are eligible for carrying traffic, issue the following command:
  4. To verify the state of all fabric planes and the elapsed time, issue the following command:

Performing a Smooth Upgrade to Enhanced Switch Fabric Board (SFB2) with Minimal Impact on Traffic

This example shows how to perform a smooth upgrade from the Switch Fabric Board (SFB) to the enhanced Switch Fabric Board (SFB2) on the MX2000 line of routers. A smooth upgrade helps reduce network downtime because of 7+1 fabric redundancy. When one SFB is being upgraded to SFB2, the other 7 SFBs are available to handle the traffic.

Note:

On MX2010 and MX2020 routers, if you have installed the Junos Continuity software package or if the router is not configured to allow multiple versions of the SFBs to coexist, you cannot perform a smooth upgrade from SFB to SFB2.

When not using a smooth upgrade, use one of the following methods to upgrade to SFB2:

  • Power off the router, replace the SFB with SFB2, and then power on the router.

  • Take both the Routing Engines offline, replace the SFB with SFB2, and then bring both the Routing Engines online.

Requirements

This example uses the following hardware and software components:

  • MX2020 router with dual Routing Engines

  • 8 Switch Fabric Boards (SFBs)

  • 8 enhanced Switch Fabric Boards (SFB2s)

  • Junos OS Release 16.1R1 or later release

Before you begin the smooth upgrade, ensure that you:

  • Prepare the router and install the version of Junos OS Release that supports the enhanced Switch Fabric Board (SFB2).

  • Verify that the existing SFBs are online and operational and also check the status of the fabric planes.

For more information about what you must do before you commence smooth upgrade, see Before you Begin the Smooth Upgrade Process.

Overview

The smooth upgrade process is used to upgrade from Switch Fabric Board (SFB) to enhanced Switch Fabric Board (SFB2) with minimal traffic impact. The existing SFBs are replaced one by one, in any order, by the new SFB2s. Because you are replacing a single SFB at a time, the remaining SFBs handle the traffic and so there is minimal impact to traffic. SFB2 is supported only on MX2020 and MX2010 routers.

Topology

This example shows how to perform a smooth upgrade on an MX2020 router that has eight SFBs. The 8 SFBs are replaced with 8 enhanced switch fabric boards (SFB2). First, initiate the smooth upgrade process and then take a single SFB offline. Replace the SFB with an SFB2, and then bring the SFB2 online. You can then repeat the steps for the other seven SFBs.

After you upgrade all the SFBs to SFB2s, the fabric bandwidth per slot of MPC8E and MPC9E on the MX2020 router is increased from 11 Gbps to 25 Gbps. However, the upgrade does not impact the fabric bandwidth per slot of MPC7.

Configuration

To upgrade from SFB to SFB2, perform the following tasks:

Initiating the Smooth Upgrade Process

Step-by-Step Procedure

By default, the MX2000 line of routers do not support both SFB and SFB2 at the same time. However, when you initiate the smooth upgrade process, the router can support both SFB and SFB2 at the same time. So, before you replace an SFB with an SFB2, you must initiate the smooth upgrade process.

  1. In configuration mode, at the [edit] hierarchy level, Initiate the smooth upgrade process for the SFBs.

  2. Commit the changes by using the commit statement and exit the configuration mode.

  3. In operational mode, verify that you have initiated the smooth upgrade process.

Performing the Smooth Upgrade

Step-by-Step Procedure

  1. In operational mode, take the SFBs offline. There is no specific order that needs to be maintained. In this example, you start with the SFB in slot 7 first.

  2. Verify that the SFB is offline.

  3. Replace the SFB that is offline with the enhanced SFB (SFB2). Minimal traffic loss is expected as only a single SFB is replaced and other seven SFBs are operational and handle the traffic.

  4. In operational mode, bring the SFB2 online.

  5. Verify that the SFB2 is online.

  6. Repeat Step 3 through Step 5 for upgrading the other SFBs. We recommend that you upgrade fabric boards one at a time for minimal traffic impact.

Terminating the Smooth Upgrade Process

Step-by-Step Procedure

After all the SFBs are upgraded to the enhanced SFB (SFB2), you can terminate the smooth upgrade process. When the smooth upgrade process is initiated, SFB and SFB2 can coexist on the same router. When you terminate the smooth upgrade process, the router can have only SFB or SFB2 and not both at the same time.

  1. In configuration mode, at the [edit] hierarchy level, terminate the smooth upgrade process.

    Note:

    You can also use the delete chassis state sfb-upgrade command to terminate the smooth upgrade process.

  2. Commit the changes by using the commit statement and exit configuration mode.

  3. In operational mode, verify that you have initiated the smooth upgrade process.

Verification

To confirm that you have upgraded SFB to SFB2 on the MX2020 router, perform these tasks:

Verifying That the Switch Fabric Board (SFB) is Offline

Purpose

To verify that the SFB on a particular slot, for instance slot 1, is offline.

Action

From operational mode, enter the show chassis fabric fpcs command.

From operational mode, enter the show chassis fabric summary command.

Meaning

The SFB in Slot 1 has been taken offline.

Verifying That the Enhanced Switch Fabric Board (SFB2) is Online

Purpose

To verify that the enhanced switch fabric board (SFB2) inserted in the same slot (slot 1) is online.

Action

From operational mode, enter the show chassis fabric fpcs command.

From operational mode, enter the show chassis fabric summary command.

Meaning

The SFB2 that replaced the SFB on slot 1 is online and operational.

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