RUGGEDCOM ROS
User Guide
Chapter 5
Setup and Configuration
Link Aggregation and Layer 2 Features
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• Enabling STP is the best way for handling link redundancy in switch-to-switch connections composed of more
than one physical link. If STP is enabled and increased bandwidth is not required, Link Aggregation should not
be used because it may lead to a longer fail-over time.
Section 5.11.1.2
Link Aggregation and Layer 2 Features
Layer 2 features (e.g. STP, VLAN, CoS, Multicast Filtering) treat a port trunk as a single link.
• If the Spanning Tree Protocol (STP) puts an aggregated port in blocking/forwarding, it does it for the whole port
trunk.
• If one of the aggregated ports joins/leaves a multicast group (e.g. via IGMP or GMRP), all other ports in the
trunk will join/leave too.
• Any port configuration parameter (e.g. VLAN, CoS) change will be automatically applied to all ports in the trunk.
• Configuration/status parameters of the secondary ports will not be shown and their port numbers will be simply
listed next to the primary port number in the appropriate configuration/status UI sessions.
• When a secondary port is added to a port trunk, it inherits all the configuration settings of the primary port.
When this secondary port is removed from the port trunk, the settings it had previous to the aggregation are
restored.
Section 5.11.1.3
Link Aggregation and Physical Layer Features
Physical layer features (e.g. physical link configuration, link status, rate limiting, Ethernet statistics) will still treat
each aggregated port separately.
• Physical configuration/status parameters will NOT be automatically applied to other ports in the trunk and will
be displayed for each port as usual.
• Make sure that only ports with the same speed and duplex settings are aggregated. If auto-negotiation is used,
make sure it is resolved to the same speed for all ports in the port trunk.
• To get a value of an Ethernet statistics counter for the port trunk, add the values of the counters for all ports in
the port trunk.
Section 5.11.2
Managing Port Trunks
The following sections describe how to configure and manage port trunks:
•
Section 5.11.2.1, “Viewing a List of Port Trunks”
•
Section 5.11.2.2, “Adding a Port Trunk”
•