In the past, the only option to provide redundant Ethernet on dedicated network adapters for IBM i was a VIRTUALIP ‘interface’. Starting with IBM i 7.1 TR3, there is a new feature called Link aggregation. It is much better and much easier for implementation than VIPA.
VIPA configuration requires 2 physical interface, and 3 public IPs. The traffic is routed only thru one interface, while the second is a backup only. Moreover, the configuration process is kind of complicated.
The other option is provision TCP traffic thru VIOS (SEA) to an IBM i host. For someone who has VIOS skills it is easy, but for IBM i stuff, it is usually ‘mission impossible’. Also the SEA brings additional layer, a machine needs extra CPU cycles to handle TCP traffic, and such configuration is not that fast as direct attach adapters .
Some time ago, IBM introduced the link aggregation feature. It allows trunk two physical adapters to a single logical device.
What is needed for such configuration
- two physical Ethernet adapters/ports, or two logical ports provisioned by SR-IOV adapters, or two interfaces delivered by two HEA’s
- the ports need to be connected to EtherChannel capable switch or switch pair. If you use two switches they must be configured in a Virtual Link Aggregation Group (VLAG) or Virtual Port Channel.
- only 1 public IP address
With this configuration you acquire
- Resilience – a system is connected thru independent adapters, switches
- Performance – both adapters are actively used to handle TCP traffic. If you use two adapters 1 Gb each, theoretically you get 2Gb bandwidth
Below you can see how to configure it
Here is an Lpar with two logical interfaces delivered by two independent SR-IOV adapters.
These ports looks following on the Green screen.
Create a Line Description type *AGG with the specific resources by command.
If your have ports correctly configures on switches, just add a IP address by ADDTCPIFC command. Vary on the interface and start use it.
In my humble opinion , if you don’t want use SEA, Link aggregation with SR-IOV adapters is the most efficient configuration.
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