User`s manual

EDS-828 Series Featured Functions
3-14
Using Port Trunking
Link Aggregation allows one or more links to be aggregated together to form a Link Aggregation Group. A MAC
client can treat Link Aggregation Groups as if they were a single link.
The EDS-828’s Port Trunking feature allows devices to communicate by aggregating up to four links in parallel, with a maximum of
eight ports for each link. If one of the eight ports fails, the other seven ports will provide back up and share the
traffic automatically.
Port trunking can be used to combine up to eight ports between two EDS-828 switches. If all ports on both
switch units are configured as 100BASE-TX and they are operating in full duplex, the potential bandwidth of the
connection will be 1600 Mbps.
The Port Trunking Concept
The EDS-828 allows a maximum of 4 trunk groups, with a maximum of 8 trunk ports for each trunk group. You
can configure the trunk group to be “Static” or “LACP.” Once the trunk group is set to “LACP,” all of the ports
making up that group will be set to LACP enabled. The ports in the “Static” trunk groups, and all the non-trunk
ports that do not belong to any trunk group, will be set to LACP disabled. When the port is set to LACP enabled,
it will exchange LACP PDU with its link partner, and will result in “Forwarding.” If all of the ports in the same
group are “Blocked” or “Disabled” or “Down” (link-down), the trunk group will not work, and the user will see
“LACP Failed” for that trunk group in the user interface.
Port Trunking applies to connections between backbone devices as well as to connections in other network
areas where traffic bottlenecks exist. Port Trunking provides the following benefits:
• Gives you more flexibility in setting up your network connections, since the bandwidth of a link can be
expanded to 8 times the original bandwidth.
• Load sharing—MAC Client traffic may be distributed across multiple links.
Keep the following points in mind when configuring port trunking:
• To avoid broadcast storms or loops in your network while configuring a trunk, first disable or disconnect
all ports that you want to add to the trunk or remove from the trunk. After you finish configuring the trunk,
enable or re-connect the ports.
• Up to 4 port trunking groups (designated Trk1, Trk2, Trk3, Trk4) can be used for each EDS-828.
• Up to 8 ports can be inserted into each port trunk group. The EDS-828 allows a maximum of 4 “Standby” ports for
each LACP trunk group. In another words, a maximum of 12 ports can belong to each LACP trunk group.
• The same transmission speed must be assigned to all ports belonging to one port trunking group. E.g.,
100M Full, 100M Half, 10M Full, or 10M Half. The auto-negotiation function should be disabled for these
ports.
• Full duplex operation only—Link Aggregation is supported only on point-to-point links with MACs
operating in full duplex mode.
• Multipoint Aggregations
—The mechanisms specified in this clause do not support aggregations among
more than two systems.