Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 437)

Configuring Link Aggregation
● Link aggregation overview............................................................................................ 437
● Link aggregation setup..................................................................................................439
Link aggregation overview
Link aggregation allows you to bundle multiple physical Ethernet links to form a single logical trunk
providing enhanced performance and redundancy. The aggregated trunk is referred to as a Link
Aggregation Group (LAG). The LAG is viewed as a single link by connected devices, the Spanning Tree
Protocol, IEEE 802.1Q VLANs, and so on. When one physical link in the LAG fails, the other links stay
up and there is no disruption to traffic.
To configure links to form a LAG, the physical links must be the same speed and all links must go to the
same neighboring device. Link aggregation can be done by manually configuring the LAG or by
dynamically configuring the LAG using the IEEE 802.3ad Link Aggregation Control Protocol (LACP).
When queuing traffic from multiple input sources to the same output port, all input sources are given the
same weight, regardless of whether the input source is a single physical link or a trunk with multiple
member links.
NOTE
The LAG or LAG interface is also referred to as a port-channel.
The benefits of link aggregation are summarized as follows:
• Increased bandwidth (The logical bandwidth can be dynamically changed as the demand changes.)
• Increased availability
• Load sharing
• Rapid configuration and reconfiguration
The Brocade VDX family of switches supports the following trunk types:
• Static, standards-based LAG
• Dynamic, standards-based LAG using LACP
• Static, Brocade-proprietary LAG
• Dynamic, Brocade-proprietary LAG using proprietary enhancements to LACP
Link Aggregation Control Protocol
Link Aggregation Control Protocol (LACP) is an IEEE 802.3ad standards-based protocol that allows two
partner systems to dynamically negotiate attributes of physical links between them to form logical
trunks. LACP determines whether a link can be aggregated into a LAG. If a link can be aggregated into
a LAG, LACP puts the link into the LAG. All links in a LAG inherit the same administrative
characteristics.
LACP operates in two modes:
Network OS Administrator’s Guide 437
53-1003225-04