NEC N8406-022A - Manual (Page 22)

Browser-based interface 22
Trunking
Trunk groups provide super-bandwidth, multi-link connections between SmartPanel or other trunk-capable devices.
A trunk group is a group of ports that act together, combining their bandwidth to create a single, larger virtual link.
SmartPanel trunk groups are static link aggregation groups that are compatible with Cisco’s EtherChannel
technology.
The SmartPanel is statically configured to place each Port Group into a separate trunk group.
NOTE: Because all ports in a Port Group belong to the same trunk group, individual external ports cannot be
used as a regular 802.3 link. Do not plug a workstation directly into one of the SmartPanel’s external ports,
unless that is the only device plugged into the ports.
When using port trunk groups between the SmartPanel and a switch, you can create a virtual link, operating at up
to 5 Gigabits per second, depending on how many physical ports are combined.
Statistical Load Distribution
Network traffic is statistically distributed between ports in a trunk group. The SmartPanel uses the source and
destination IP address information present in each transmitted IP frame to determine load distribution. If the frame
is not an IP frame, then Layer 2 MAC addresses are used.
Each packet’s particular combination of source and destination addresses results in selecting one line in the trunk
group for data transmission. If there are enough devices feeding the trunk lines, then traffic distribution becomes
relatively even.
Built-In Fault Tolerance
Since trunk groups are comprised of multiple physical links, each trunk group is inherently fault tolerant. As long as
one connection is available, the trunk remains active.
Statistical load balancing is maintained whenever a port in a trunk group is lost or returned to service.
Trunk group configuration rules
The trunking feature operates according to specific configuration rules. When working with trunks, consider the
following rules that determine how a trunk group reacts in any network topology.
•
All trunks must originate from one device, and lead to one destination device.
•
Trunking from third-party devices must comply with Cisco® EtherChannel® technology.
•
All external ports in a Port Group must have the same configuration.
•
Only external ports in a Port Group are trunked. For Port Group configuration, see the “Port Group
configuration”.
Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP) is an IEEE 802.3ad standard for grouping several physical ports into one
logical port (known as a dynamic trunk group or Link Aggregation Group) with any device that supports the
standard. Please refer to IEEE 802.3ad-2002 for a full description of the standard.
The 802.3ad standard allows standard Ethernet links to form a single Layer 2 link using the Link Aggregation
Control Protocol (LACP). Link aggregation is a method of grouping physical link segments of the same media type
and speed in full duplex, and treating them as if they were part of a single, logical link segment. If a link in a LACP
trunk group fails, traffic is reassigned dynamically to the remaining link/s of the dynamic trunk group.