Dell PowerConnect B-FCXs Configuration Manual page 441

Load sharing for unknown unicast, multicast, and broadcast traffic
Dell PowerConnect 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).
NOTE
Table 72
for unknown unicast, multicast, and broadcast
Table 72
TABLE 72
Traffic type
L2 Bridged Non-IP
L2 Bridged IPv4 TCP/UDP
L2 Bridged IPv4 Non-TCP/UDP
L2 Bridged IPv6 TCP/UDP
L2 Bridged IPv6 Non-TCP/UDP
Adding Layer 2 information to trunk hash output
FastIron Stackable devices support the option to include Layer 2 information in the trunk hash
calculation for IP packets. Use the following CLI command.
PowerConnect(config)# trunk hash-options include-layer2
This command adds Layer 2 information (text in bold) to the following load-balancing parameters.
1. Non-IP: Source MAC, Destination MAC
2. IPv4 TCP/UDP: Source IP, Destination IP, Source TCP/UDP Port, Destination TCP/UDP Port,
3. IPv4 Non-TCP/UDP: Source IP, Destination IP, Source MAC, Destination MAC
PowerConnect B-Series FCX Configuration Guide
53-1002266-01
do not include unknown unicast, multicast, and broadcast traffic. Refer to
describes how the FastIron Stackable devices load balance traffic.
Trunk group load sharing on FastIron Stackable devices
Source MAC, Destination MAC
Trunk group overview
traffic".
Load balancing method
Source MAC, Destination MAC
Source IP, Destination IP, Source TCP/UDP Port,
Destination TCP/UDP Port
Source IP, Destination IP
Source IP, Destination IP, Flow Label, Source TCP/UDP
Port, Destination TCP/UDP Port
Source IP, Destination IP, Flow Label
12
"Load sharing
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