Link Aggregation (Etherchannel) Pseudo Device - IBM p5 590 System Handbook

Standard distribution mode selects the adapter for the outgoing packets by
algorithm. The adapter selection algorithm uses the last byte of the destination IP
address (for TCP/IP traffic) or MAC address (for ARP and other non-IP traffic).
Therefore all packets to a specific IP-address will always go through the same
adapter. There are other adapter selection algorithms based on source,
destination, or a combination of source and destination ports available.
round robin.
EtherChannel provides one further distribution mode called This
mode will rotate through the adapters, giving each adapter one packet before
repeating. The packets may be sent out in a slightly different order than they
were given to the EtherChannel. It will make the best use of its bandwidth, but
consider that it also introduces the potential for out-of-order packets at the
receiving system. This risk is particularly high when there are few, long-lived,
streaming TCP connections. When there are many such connections between a
host pair, packets from different connections could be intermingled, thereby
decreasing the chance of packets for the same connection arriving out-of-order.
To avoid the loss of network connectivity by switch failure, EtherChannel and Link
Aggregation can provide a backup adapter. The backup adapter should be
connected to a different switch than the adapter of the aggregation. Now in case
of switch failure the traffic can be moved with no disruption of user connections to
the backup adapter.
Figure 3-10 shows the aggregation of three plus one adapters to a single pseudo
Ethernet device including a backup feature.
Figure 3-10 Link Aggregation (EtherChannel) pseudo device
IBM Eserver p5 590 and 595 System Handbook
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