Brocade Converged Enhanced Ethernet Administrator's Guide v6.1.2_cee (53-1001258-01, June 2009)

68 Converged Enhanced Ethernet Administrator’s Guide
53-1001258-01
Link aggregation overview
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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 8000 CEE switch 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.
LAGs
You can configure a maximum of 24 LAGs with up to 16 links per standard LAG and four links per
Brocade-proprietary LAG. Each LAG is associated with an aggregator. The aggregator manages the
Ethernet frame collection and distribution functions.
On each port, link aggregation control:
• Maintains configuration information to control port aggregation.
• Exchanges configuration information with other devices to form LAGs.
• Attaches ports to and detaches ports from the aggregator when they join or leave a LAG.
• Enables or disables an aggregator’s frame collection and distribution functions.
Each link in the Brocade 8000 CEE switch can be associated to a LAG; a link cannot be associated
to more than one LAG. The process of adding and removing links to and from a LAG is controlled
either statically, dynamically, or through LACP.
Each LAG consists of the following components:
• A MAC address that is different from the MAC addresses of the LAG’s individual member links.
• An interface index for each link to identify the link to neighboring devices.
• An administrative key for each link. Only links having the same administrative key value can be
aggregated into a LAG. On each link configured to use LACP, LACP automatically configures an
administrative key value equal to the port-channel identification number.
Figure 6 and Figure 7 show typical IP SAN configurations using LAGs. In a data center the Brocade
8000 CEE switch fits into the top-of-the-rack use case where all the servers in a rack are connected
to the Brocade 8000 CEE switch through Twinax copper or optical fiber cable. The database server
layer connects to the top-of-the-rack Brocade 8000 CEE switch which is located in the network
access layer.
The Brocade 8000 CEE switch connects to Layer 2/Layer 3 aggregation routers which provide
access into the existing LAN. This connectivity is formed in a standard V-design or square-design.
Both designs use the LAG as the uplink to provide redundancy and improved bandwidth.
The Brocade 8000 CEE switch interoperates with all of the major Layer 2/Layer 3 aggregation
routers including Foundry Networks, Cisco Systems, and Force10 Networks.