Brocade Multi-Service IronWare Switching Configuration Guide (Supporting R05.6.00) - Manual (Page 177)

Multi-Service IronWare Switching Configuration Guide 147
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LAG load sharing
6
FIGURE 6 Example of a 1-port keepalive LAG
Figure 7 shows an example of a valid 2-port LAG between devices where the ports on each end are
on the same interface module. Ports in a valid 2-port LAG on one device are connected to two ports
in a valid 2-port LAG on another device.
FIGURE 7 Example of 2-port LAG
LAG load sharing
Brocade devices can be configured for load sharing over a LAG using hash-based load sharing.
Hash based load sharing
Brocade NetIron CES and Brocade NetIron CER devices share the traffic load evenly across the
ports in LAG group, while ensuring that packets in the flow are not reordered. Individual flows are
assigned a LAG index to identify them.
Traffic from each flow is then distributed across the ports in the LAG group using a hash index as
follows:
The hash value is calculated based on the packet:
• hash[5:0] = MAC_SA[5:0]^MAC_DA[5:0];
If the packet is IP (v4 or v6), the hash is further calculated as the following:
• hash[5:0] = hash[5:0]^SIP[5:0]^SIP[21:16]^DIP[5:0]^DIP[21:16];
If the packet is TCP or UDP, the hash is further calculated as the following:
• hash[5:0] = hash[5:0]^L4_SrcPort[5:0]^L4_SrcPort[13:8]^L4_TrgPort[5:0]^L4_TrgPort[13:8];