802.3Ad Link Aggregation Principles - Avaya 8600 Configuration Manual

Link aggregation fundamentals
During receive operations, these blocks distinguish among Marker Request, Marker
Response, MAC Client Protocol Data Units (PDUs), and pass the blocks to the
appropriate entity (Marker Responder, Marker Receiver, and Collector, respectively).
• Aggregator:
The combination of frame distribution and collection, and aggregator Parser/
Multiplexers.
• Aggregation Control:
This block configures and controls link aggregation. It incorporates LACP for the
automatic communication of aggregation capabilities between systems and automatic
configuration of link aggregation.
• Control Parser/Multiplexers:
During transmission operations, these blocks pass frame transmission requests from the
aggregator and Control entities to the appropriate port.
During receive operations, these blocks distinguish Link Aggregation Control Protocol
Data Units (LACPDUs) from other frames. The blocks pass, passing the LACPDUs to the
appropriate sublayer entity and all other frames to the aggregator.

802.3ad link aggregation principles

Link aggregation allows you to group switch ports together to form a link group to another
switch or server. Link groups increase aggregate throughout between devices and provide link
redundancy.
Link aggregation employs the following principles and concepts:
• A MAC client communicates with a set of ports through an aggregator, which presents a
standard IEEE 802.3 service interface to the MAC client. The aggregator binds to one or
more ports within a system.
• The aggregator distributes frame transmissions from the MAC client to various ports,
collects received frames from the ports, and transparently passes the frames to the MAC
client.
• A system can contain multiple aggregators serving multiple MAC clients. A port binds to
a single aggregator at a time. A MAC client is served by a single aggregator at a time.
• The Link Aggregation Control function binds ports to aggregators within a system. The
control function aggregates links, binds the system ports to an appropriate aggregator,
and monitors conditions to determine when a change in aggregation is needed. Network
managers can manually provide link aggregation control by manipulating the link
aggregation state variables (for example, keys). You can also use LACP to automatically
determine, configure, bind, and monitor link aggregation.
22 Configuration — Link Aggregation, MLT, and SMLT
Comments? infodev@avaya.com
January 2012