Brocade Network OS Administrator’s Guide v4.1.1 - Manual (Page 438)

• Passive mode — LACP responds to Link Aggregation Control Protocol Data Units (LACPDUs)
initiated by its partner system but does not initiate the LACPDU exchange.
• Active mode — LACP initiates the LACPDU exchange regardless of whether the partner system
sends LACPDUs.
Dynamic link aggregation
Dynamic link aggregation uses LACP to negotiate which links can be added and removed from a LAG.
Typically, two partner systems sharing multiple physical Ethernet links can aggregate a number of
those physical links using LACP. LACP creates a LAG on both partner systems and identifies the LAG
by the LAG ID. All links with the same administrative key and all links that are connected to the same
partner switch become members of the LAG. LACP continuously exchanges LACPDUs to monitor the
health of each member link.
Static link aggregation
In static link aggregation, links are added into a LAG without exchanging LACPDUs between the
partner systems. The distribution and collection of frames on static links is determined by the
operational status and administrative state of the link.
LACP configuration guidelines and restrictions
This section applies to standards-based and Brocade-proprietary LAG configurations, except where
specifically noted otherwise.
Follow these LACP configuration guidelines and restrictions when configuring LACP:
• All ports on the Brocade VDX hardware can operate only in full-duplex mode.
• On Brocade-proprietary LAGs only, all LAG member links must be part of the same port-group.
• Interfaces configured as "switchport" interfaces cannot be aggregated into a LAG. However, a LAG
can be configured as a switchport.
Brocade-proprietary aggregation
Brocade-proprietary aggregation is similar to standards-based link aggregation but differs in how the
traffic is distributed. It also has additional rules that member links must meet before they are
aggregated:
• The most important rule requires that there is not a significant difference in the length of the fiber
between the member links, and that all member links are part of the same port-group. For example,
the Brocade VDX 6720-24 has two port groups: te0/1 to te0/12 and te0/13 to te0/24. All of the
member links should be members of either groups 1 to 12 or groups 13 to 24, but not both.
• A maximum of four Brocade LAGs can be created per port-group.
LAG distribution process and conditions
The LAG aggregator is associated with the collection and distribution of Ethernet frames. The
collection and distribution process is required to guarantee the following:
• Inserting and capturing control PDUs.
• Restricting the traffic of a given conversation to a specific link.
• Load balancing between individual links.
• Handling dynamic changes in LAG membership.
Dynamic link aggregation
438 Network OS Administrator’s Guide
53-1003225-04