Dynamic Link Aggregation Overview; Dynamic Link Aggregation Operation - Alcatel OmniSwitch 6624 Network Configuration Manual

Configuring Dynamic Link Aggregation

Dynamic Link Aggregation Overview

Link aggregation allows you to combine 2, 4, or 8 physical connections on a single switch or 2, 4, 8, or 16
links in a stack into large virtual connections known as link aggregation groups. You can create up to 4
link aggregation (both dynamic and static) groups on a single OmniSwitch 6624 or 6600-U24 switch, up
to 8 link aggregation groups on a single 6648 switch, and up to 30 link aggregation groups per stack.
You can create Virtual LANs (VLANs), configure Quality of Service (QoS) conditions, 802.1Q framing,
and other networking features on link aggregation groups because switch software treats these virtual links
just like physical links. (See
link aggregation interacts with other software features.)
Link aggregation groups are identified by unique MAC addresses, which are created by the switch but can
be modified by the user at any time. Load balancing is performed on the egress side of the switch by the
link aggregation groups to evenly balance traffic flows on the physical links. Load balancing distributes
traffic by using a "hash coding" of source and destination MAC addresses. Ports must be the same speed
within the same aggregate group.
Alcatel's link aggregation software allows you to configure the following two different types of link
aggregation groups:
Static link aggregate (OmniChannel) groups
•
Dynamic link aggregate groups
•
This chapter describes dynamic link aggregation. For information on static link aggregation (also known
as OmniChannel), please refer to

Dynamic Link Aggregation Operation

Dynamic aggregate groups are virtual links between two nodes consisting of 2, 4, or 8 10 Mbps, 100
Mbps, or 1 Gbps fixed physical links on a single switch or 2, 4, 8, 16 10 Mbps, 100 Mbps, or 1 Gbps fixed
physical links on a stack. Dynamic aggregate groups use the standard IEEE 802.3ad Link Aggregation
Control Protocol (LACP) to dynamically establish the best possible configuration for the group. This task
is accomplished by special Link Aggregation Control Protocol Data Unit (LACPDU) frames that are sent
and received by switches on both sides of the link to monitor and maintain the dynamic aggregate group.
The figure on the following page shows a dynamic aggregate group that has been configured between
Switch A and Switch B. The dynamic aggregate group links four ports on Switch A to four ports on
Switch B.
OmniSwitch 6624/6648 Network Configuration Guide
"Relationship to Other Features" on page 11-9
Chapter 10, "Configuring Static Link Aggregation."
April 2004
Dynamic Link Aggregation Overview
for more information on how
page 11-7