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Configuring Switching Control Board Redundancy
Follow the steps below to configure switching control board redundancy.
Configuring CFEB Redundancy on the M10i Router
The Compact Forwarding Engine Board (CFEB) on the M10i router provides route lookup, filtering, and switching on incoming data packets, and then directs outbound packets to the appropriate interface for transmission to the network. The CFEB communicates with the Routing Engine using a dedicated 100-Mbps Fast Ethernet link that transfers routing table data from the Routing Engine to the forwarding table in the integrated ASIC. The link is also used to transfer from the CFEB to the Routing Engine routing link-state updates and other packets destined for the router that have been received through the router interfaces.
To configure a CFEB redundancy group, include the following statements at the
[edit chassis redundancy] hierarchy level:
[edit chassis redundancy] cfeb slot-number (always | preferred);
slot-number can be 0 or 1.
always defines the CFEB as the sole device.
preferred defines a preferred CFEB.
To manually switch CFEB primary role, issue the request chassis cfeb master
switch command. To view CFEB status, issue the show chassis
cfeb command.
See Also
Configuring FEB Redundancy on the M120 Router
To configure a FEB redundancy group for the M120 router,
include the following statements at the [edit chassis redundancy
feb] hierarchy level:
[edit chassis redundancy feb] redundancy-group group-name { description description; feb slot-number (backup | primary); no-auto-failover; }
group-name is the unique name for the redundancy group. The maximum length is 39 alphanumeric characters.
slot-number is the slot number of each FEB you want to include in the redundancy group. The range is from 0 through 5. You must specify exactly one FEB as a backup FEB per redundancy group. Include the backup keyword when configuring the backup FEB and make sure that the FEB is not connected to an FPC.
Include the primary keyword to optionally specify one primary FEB per redundancy group. When the primary keyword is specified for a particular FEB, that FEB is configured for 1:1 redundancy. With 1:1 redundancy, the backup FEB contains the same forwarding state as the primary FEB. When no FEB in the redundancy group is configured as a primary FEB, the redundancy group is configured for n:1 redundancy. In this case, the backup FEB has no forwarding state. When a FEB fails, the forwarding state must be downloaded from the Routing Engine to the backup FEB before forwarding continues.
A combination of 1:1 and n:1 redundancy is possible when more than two FEBs are present in a group. The backup FEB contains the same forwarding state as the primary FEB, so that when the primary FEB fails, 1:1 failover is in effect. When a nonprimary FEB fails, the backup FEB must be rebooted so that the forwarding state from the nonprimary FEB is installed on the backup FEB before it can continue forwarding.
You can optionally include the description statement
to describe a redundancy group.
Automatic failover is enabled by default. To disable automatic
failover, include the no-auto-failover statement. If you
disable automatic failover, you can perform only a manual switchover
using the operational command request chassis redundancy feb slot slot-number switch-to-backup.
To view FEB status, issue the show chassis feb command.
For more information, see the CLI Explorer.
See Also
Example: Configuring FEB Redundancy on M120 Routers
In the following configuration, two FEB redundancy groups are created:
A FEB redundancy group named group0 with the following properties:
Contains three FEBs (0 through 2).
Has a primary FEB (2).
Has a unique backup FEB (0).
Automatic failover is disabled.
When an active FEB in group0 fails, automatic failover to the backup FEB does not occur. For group0, you can only perform a manual switchover.
A FEB redundancy group named group1 with the following properties:
Two FEBs (3 and 5). There is no primary FEB.
A unique backup FEB (5).
Automatic failover is enabled by default.
When feb 3 in group1 fails, an automatic failover occurs.
Because you must explicitly configure an FPC not to connect to the backup FEB, connectivity is set to none between fpc 0 and feb 0 and between fpc 5 and feb 5.
For information about the fpc-feb-connectivity statement, see the Junos OS Administration Library for Routing Devices.
FPC to primary FEB connectivity is not explicitly configured, so by default, the software automatically assigns connectivity based on the numerical order of the FPCs.
[edit]
chassis {
fpc-feb-connectivity {
fpc 0 feb none;
fpc 5 feb none;
}
redundancy feb {
redundancy-group group0 {
description “Interfaces to Customer X”;
feb 2 primary;
feb 1;
feb 0 backup;
no-auto-failover;
}
redundancy-group group1 {
feb 3;
feb 5 backup;
}
}
See Also
Configuring SFM Redundancy on M40e and M160 Routers
By default, the Switching and Forwarding Module (SFM)
in slot 0 is the primary and the SFM in slot 1 is the backup. To modify
the default configuration, include the sfm statement at
the [edit chassis redundancy] hierarchy level:
[edit chassis redundancy] sfm slot-number (always | preferred);
On the M40e router, slot-number is 0 or 1. On the M160 router, slot-number is 0 through 3.
always defines the SFM as the sole device.
preferred defines a preferred SFM.
To manually switch primary role between SFMs, issue the request chassis sfm master switch command. To view SFM status,
issue the show chassis sfm command. For more information,
see the CLI Explorer.
See Also
Configuring SSB Redundancy on the M20 Router
For M20 routers with two System and Switch Boards (SSBs),
you can configure which SSB is the primary and which is the backup.
By default, the SSB in slot 0 is the primary and the SSB in slot 1
is the backup. To modify the default configuration, include the ssb statement at the [edit chassis redundancy] hierarchy
level:
[edit chassis redundancy] ssb slot-number (always | preferred);
slot-number is 0 or 1.
always defines the SSB as the sole device.
preferred defines a preferred SSB.
To manually switch primary role between SSBs, issue the request chassis ssb master switch command.
To display SSB status information, issue the show chassis
ssb command. The command output displays the number of times
the primary role has changed, the SSB slot number, and the current
state of the SSB: primary, backup, or empty. For more information,
see the CLI Explorer.
See Also
Configuring the Junos OS to Support Redundancy on Routers Having Multiple Routing Engines or Switching Boards
For routers that have multiple Routing Engines or these multiple switching control boards: Switching and Forwarding Modules (SFMs), System and Switch Boards (SSBs), Forwarding Engine Boards (FEBs), or Compact Forwarding Engine Boards (CFEBs), you can configure redundancy properties.
To configure redundancy, include the following redundancy statements
at the [edit chassis] hierarchy level:
redundancy {
cfeb slot (always | preferred);
failover {
on-disk-failure
on-loss-of-keepalives;
}
feb {
redundancy-group group-name {
feb slot-number (backup | primary);
description description;
no-auto-failover;
}
}
graceful-switchover;
keepalive-time seconds;
routing-engine slot-number (master | backup | disabled);
sfm slot-number (always | preferred);
ssb slot-number (always | preferred);
}