User`s guide

9033194 SmartSTACK ELS100-24 Firmware Revision 2.01 3
A.3 SmartTrunking
SmartTrunking is a link aggregation feature that allows multiple physical
ports of the switch to be aggregated together to form a single logical
connection between network devices. All physical connections in the
logical connection carry traffic, as compared with previous software
versions in which Spanning Tree would block all traffic on all but one of
the physical connections.
Background
A trunk is a group of ports that perform as a single logical port, connecting
the ELS100-24 switch with another network device. Compared with a
single port, the group of ports in a trunk feature increased bandwidth and
provide a level of connection resiliency - when one physical port link in the
trunk group goes down, the overall connection is not lost. When a port in
a trunk group is removed (link goes down or a cable is severed), traffic on
that port will be redistributed to other ports in the trunk group.
In the example in Figure A-2 below, three switches are connected
(stacked) through a series of trunk groups. Two physical ports are
combined to form each trunk group. The fiber ports in the top switch form
Trunk 1 which carries traffic to the network backbone.
Figure A-2. Trunking Application Example
SmartTrunking uses the DEC Hunt Group protocols - PLAP and LLAP -
to automatically establish and maintain a trunk connection. Use of these
protocols can be enabled or disabled as desired. When the protocols are