Resilience Feature Overview; What Are Resilient Links - 3Com 3C17205-US - Corp SUPERSTACK 3 SWITCH 4400 24PORT Implementation Manual

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HAPTER SING
Resilience Feature
Overview
What are Resilient
Links?
R F
ESILIENCE EATURES
Resilient links and STP/RSTP cannot both be used on the network at the
same time. Table 3 lists the key differences between each feature, so you
can evaluate the benefits of each to determine which feature is most
suitable for your network.
Table 3 Resilient Links and Spanning Tree Protocols — Key Differences
Resilient Links
User configures each
Switch separately.
Manual configuration.
Within 5 seconds restores
an active connection from
a standby link.
3Com recommends that you use the Rapid Spanning Tree Protocol
feature (default enabled) to provide optimum performance for your
network and ease of use.
The Switch also supports aggregated links which increase bandwidth and
also provide resilience against individual link failure. Aggregated links will
operate with STP enabled, but will not operate on ports that are part of a
resilient link pair. For more information, see
page 29.
The resilient link feature enables you to protect critical links and prevent
network downtime if those links fail. A resilient link is comprised of a
resilient link pair containing a main link and a standby link. If the main
link fails, the standby link quickly and automatically takes over the task of
the main link and becomes the "active link".
The resilient link pair is defined by specifying a main port and a standby
port at one end of the link. During normal operation, the main port is
enabled and the standby port is disabled. If the main link fails, the main
port is disabled and the standby port is enabled. If the main link becomes
operational, you can then re-enable the main port and disable the
standby port again.
There are two user configurable modes of operation for resilient links:
Spanning Tree Protocol
STP is disabled by default.
User enables STP on each
Switch.
Automatic configuration.
Up to 30 second delay on
link failure to restoring a
network connection.
Aggregated Links
Rapid Spanning Tree
Protocol
RSTP is enabled by default.
Automatic configuration.
Within 5 seconds restores
a network connection.
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