Converged Enhanced Ethernet Administrator's Guide v6.4.0 (53-1001761-01, June 2010)

66 Converged Enhanced Ethernet Administrator’s Guide
53-1001761-01
Link aggregation overview
6
DRAFT: BROCADE CONFIDENTIAL
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 FCoE hardware can be associated with a LAG; a link cannot be associated
with 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 7 and Figure 8 show typical IP SAN configurations using LAGs. In a data center the Brocade
8000 switch fits into the top-of-the-rack use case where all the servers in a rack are connected to
the Brocade 8000 switch through Twinax copper or optical fiber cable. The database server layer
connects to the top-of-the-rack Brocade 8000 switch which is located in the network access layer.
The Brocade 8000 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.