Port Management
Link Aggregation
Cisco 350XG & 550XG Series 10G Stackable Managed Switches
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Link Aggregation Overview
Link Aggregation Control Protocol (LACP) is part of the IEEE specification (802.3az)
that enables you to bundle several physical ports together to form a single logical
channel (LAG). LAGs multiply the bandwidth, increase port flexibility, and provide
link redundancy between two devices.
Two types of LAGs are supported:
•
Static
—The ports in the LAG are manually configured. A LAG is static if
LACP is disabled on it. The group of ports assigned to a static LAG are
always active members. After a LAG is manually created, the LACP option
cannot be added or removed, until the LAG is edited and a member is
removed (which can be added back prior to applying), the LACP button
then become available for editing.
•
Dynamic
—A LAG is dynamic if LACP is enabled on it. The group of ports
assigned to dynamic LAG are candidate ports. LACP determines which
candidate ports are active member ports. The non-active candidate ports
are
standby
ports ready to replace any failing active member ports.
Load Balancing
Load Balancing
Traffic forwarded to a LAG is load-balanced across the active member ports, thus
achieving an effective bandwidth close to the aggregate bandwidth of all the
active member ports of the LAG.
Traffic load balancing over the active member ports of a LAG is managed by a
hash-based distribution function that distributes Unicast and Multicast traffic
based on Layer 2 or Layer 3 packet header information.
The device supports two modes of load balancing:
•
By MAC Addresses—Based on the destination and source MAC addresses
of all packets.
•
By IP and MAC Addresses—Based on the destination and source IP
addresses for IP packets, and destination and source MAC addresses for
non-IP packets.
