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Configuring Multi-chassis Link Aggregation
MCLAG Overview
OmniSwitch AOS Release 7 Network Configuration Guide
June 2013
page 10-9
MCLAG Overview
Multi Chassis Link Aggregation (MCLAG) addresses resiliency at the edge of the network by enabling
dual homing of any standards-based edge switches to a pair of aggregation switches resulting in a Layer 2
multi-path infrastructure. MCLAG provides increased bandwidth, load balancing and resiliency for L2
edge devices in a network.
An edge switch is dual homed to two Omniswitch through Link Aggregation Control Protocol or Static
Aggregation. MCLAG enhances link aggregation by eliminating blocked redundant links to provide fast
switch over between edge and core switches without implementing Spanning Tree. Dual homed uplinks
are active/active and can provide sub-second traffic convergence for link fail.
MCLAG Group (Domain) Network Example
MCLAG Concepts and Components
MCLAG is an OmniSwitch feature that requires specific building blocks to provide full functionality. The
following sections highlight the various components of MCLAG.
The Multi-Chassis Domain
is a virtual entity consisting of two peer switches, the virtual fabric link
between the peer switches, all of the MCLAG aggregate ports, and the edge devices connected to the
aggregate ports.
Multi-Chassis Manager (MCM)
is an Alcatel-Lucent proprietary application that provides the founda-
tion for an inter-chassis communication infrastructure that is used by applications (for example, link
aggregation) to exchange state information. This implementation of MCM:
•
Manages and monitors multi-chassis functionality and state machines.
•
Performs peer discovery and establishes the virtual fabric link.
•
Performs and monitors MCLAG parameter consistency checks between the peer switches.
•
Runs the hello protocol between the peer switches.
Multi-Chassis Infra-
structure that allows
applications to exchange
state information over the
virtual fabric link
Edge
Aggregation
MC-LAG-1
Virtual Fabric
Link
MC-LAG: Multi-Chassis
Link Aggregate
All links are active
All links are active
Multi-Chassis
Domain
Multi-Chassis
Peer Switch
Multi-Chassis
Peer Switch
MC-LAG-2