Configuration Guide User guide

FastIron Configuration Guide 705
53-1002494-02
Trunk group overview
NOTE
For FCX devices only, flexible trunk group membership is supported from Web Management, but not
from SNMP. For all other FastIron devices, this feature is not supported from Web Management or
SNMP.
For configuration details, refer to “CLI syntax for configuring non-consecutive ports in a trunk
group” on page 708.
Trunk group load sharing
Brocade devices load-share across the ports in the trunk group. The method used for the load
sharing depends on the device type and traffic type (Layer 2 or Layer 3).
NOTE
Layer 2 and Layer 3 AppleTalk traffic is not load-balanced. Layer 3 routed IP or IPX traffic also is not
load balanced. These traffic types will however still be forwarded on the trunk ports.
Support for IPv6 when sharing traffic across a trunk group
Brocade devices that support IPv6 take the IPv6 address for a packet into account when sharing
traffic across a trunk group. The load sharing is performed in the same way it is for IPv4 addresses;
that is, trunk types with a traffic load that is shared based on IPv4 address information can now
use IPv6 addresses to make the load sharing decision.
Load sharing occurs as described in Table 133 or Table 134.
Load balancing for unknown unicast, multicast, and broadcast traffic
Brocade devices load balance unknown unicast, multicast, and broadcast traffic based on the
source port and VLAN ID and not on any source or destination information in the packet.
For example, when the switch receives unknown unicast, multicast, and broadcast packets, and
the packets are from the same source port, the packets are forwarded to the same port of the
trunk group. Conversely, when the switch receives unknown unicast, multicast, and broadcast
packets, and the packets are from different source ports, the packets are load balanced across all
the ports of the trunk group.
Note that this does not apply to known unicast traffic, which is always load balanced across all the
ports of a trunk group based on the traffic's Layer 2 and Layer 3 source and destination
parameters.
How trunk load sharing works
The load balancing method for bridged traffic varies depending on the traffic type. Load balancing
for routed traffic is always based on the source and destination IP addresses and protocol field (not
applicable for FastIron stackable devices).
Table 133 and Table 134 show how the different Brocade devices load balance traffic.
NOTE
Table 133 and Table 134 do not include unknown unicast, multicast, and broadcast traffic. Refer to
“Load balancing for unknown unicast, multicast, and broadcast traffic”.