Resilient Link; Introduction; Configuring And Displaying A Resilient Link - Nokia ESB26 User Manual

9. Resilient Link

Introduction

A resilient link provides a secondary backup link to protect a network against failure of an
individual link or device. The backup link becomes active only if a failure on the main link
occurs. A resilient link comprises a resilient link pair that contains a main link and a standby
link. If the main link fails, the standby link immediately takes over the task of the main link.
Under normal network conditions, the main link carries network traffic. If a signal loss is
detected, the device immediately enables the standby link for carrying the data. The standby
port assumes the profile and carries the network traffic of the main port.
A port is said to be preferred if it is always the main port as long as it has the link. Traffic will
be switched back to the main port as soon as its connection is recovered. The preferred port
can be established in several ways:
•
The port with the higher bandwidth gets the preference.
• One port is configured as preferred by the prefer port command (described
below).
Active port refers to the current active port. You can determine the active port manually, using
the active port command (described below) only if the preferred port has not been
established. By default (if you have not configured a preferred or active port, and the two
ports have the same bandwidth capacity), the active port is the first port you configure by the
ports command (described below).
Switchover time to the backup link is less than 1 second, ensuring that no session timeouts
take place and avoiding system timeouts.
NOTES • Resilient links are incompatible with a spanning tree or trunk port.
• When adding a new port to an existing trunk, the VLAN of the trunk ports is
synchronized.
• Both links of the resilient link must be included in the same VLANs, if there are
any.
• Both resilient link ports must have the same default VLAN.

Configuring and Displaying a Resilient Link

Resilient link Configuration and Viewing Commands
C o m m a n d
resilient-link
ports
MN700004 Rev 01
D e s c r i p t i o n
Enters a specific resilient link configuration mode.
Adds a port pair as a resilient link.
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