Important Points About Configuring Redundant Pairs - Dell Force10 S4810P Configuration Manual

You configure a redundant pair by assigning a backup interface to a primary interface with the
backup interface
interface remains down. If the primary fails for any reason, the backup transitions to an active UP state. If
the primary interface fails and later comes back up, it remains as the backup interface for the redundant
pair.
FTOS supports only Gigabit, 10-Gigabit, and 40-Gigabit ports and port channels as primary/backup
interfaces in redundant pairs. (A port channel is also referred to as a Link Aggregation Group (LAG). See
Chapter 23, Interfaces,
member link of a LAG, the following primary/backup interfaces are also supported:
• primary interface is a physical interface, the backup interface can be a physical interface
• primary interface is a physical interface, the backup interface can be a static or dynamic LAG
• primary interface is a static or dynamic LAG, the backup interface can be a physical interface
• primary interface is a static or dynamic LAG, the backup interface can be a static or dynamic LAG
In a redundant pair, any combination of physical and port-channel interfaces is supported as the two
interfaces in a redundant pair. For example, you can configure a static (without LACP) or dynamic (with
LACP) port-channel interface as either the primary or backup link in a redundant pair with a physical
interface.
To ensure that existing network applications see no dif ference when a primary interface in a redundant pair
transitions to the backup interface, be sure to apply identical configurations of other traffic parameters to
each interface.
If you remove an interface in a redundant link (remove the line card of a physical interface or delete a port
channel with the

Important Points about Configuring Redundant Pairs

• You may not configure any interface to be a backup for more than one interface, no interface can have
more than one backup, and a backup interface may not have a backup interface.
• Neither the active nor the backup interface may be a member of a LAG.
• The active and standby do not have to be of the same type (1G, 10G, etc).
• You may not enable any Layer 2 protocol on any interface of a redundant pair or to ports connected to
them.
In Figure 29-7, interface 3/41 is a backup interface for 3/42, and 3/42 is in the down state, as shown in
message Message
message similar to
Message 1 Configuring a Backup Layer 2 Port
02:28:04: %RPM0-P:CP %IFMGR-5-L2BKUP_WARN: Do not run any Layer2 protocols on Gi 3/41
and Gi 3/42
02:28:04: %RPM0-P:CP %IFMGR-5-OSTATE_DN: Changed interface state to down: Gi 3/42
02:28:04: %RPM0-P:CP %IFMGR-5-STATE_ACT_STBY: Changed interface state to standby: Gi
3/42
command. Initially, the primary interface is active and transmits traffic and the backup
Port Channel Interfaces on page 482
no interface port-channel
1. If 3/41 fails, 3/42 transitions to the up state, which makes the backup link active. A
Message 1 appears whenever you configure a backup port.
for more information.) If the interface is a
command), the redundant pair configuration is also removed.
switchport
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