626 Port Channel CommandsThe hashing algorithm is configurable for each LAG. Typically, anadministrator is able to choose from hash algorithms utilizing the followingattributes of a packet to determine the outgoing port:• Source MAC, VLAN, EtherType, and incoming port associated with thepacket.• Source IP and Source TCP/UDP fields of the packet.• Destination MAC, VLAN, EtherType, and incoming port associated withthe packet.• Source MAC, Destination MAC, VLAN, EtherType, and incoming portassociated with the packet.• Destination IP and Destination TCP/UDP Port fields of the packet.• Source/Destination MAC, VLAN, EtherType, and incoming portassociated with the packet.• Source/Destination IP and source/destination TCP/UDP Port fields of thepacket.Enhanced LAG HashingPowerConnect devices based on Broadcom XGS-IV silicon supportconfiguration of hashing algorithms for each LAG interface. The hashingalgorithm is used to distribute traffic load among the physical ports of theLAG while preserving the per-flow packet order.One limitation with earlier LAG hashing techniques is that the packetattributes were fixed for all type of packets. Also, there was no MODULO-Noperation involved, which can result in poor load balancing performance.As part of Release 4.0, the LAG hashing support is extended to support anEnhanced hashing mode, which has the following advantages:• MODULO-N operation based on the number of ports in the LAG.• Packet attributes selection based on the packet type. For L2 packets,Source and Destination MAC address are used for hash computation. ForIP packets, Source IP, Destination IP address, TCP/UDP ports are used.• Non-Unicast traffic and Unicast traffic is hashed using a common hashalgorithm.• Excellent load balancing performance.
