POWERVM - NIB, LA

Network Interface Backup (NIB)

Network Interface Backup (NIB) in the client partition can be used to achieve network redundancy when using two Virtual I/O Severs.

The client partition uses two virtual Ethernet adapters to create an EtherChannel that consists of one primary adapter and one backup adapter. The interface is defined on the EtherChannel. If the primary adapter becomes unavailable, the Network Interface Backup switches to the backup adapter.

A Link Aggregation of more than one active virtual Ethernet adapter is not supported (on the client -bb). Only one primary virtual Ethernet adapter plus one backup virtual Ethernet adapter are supported. To increase the bandwidth of a virtual Ethernet adapter Link Aggregation has to be done on the Virtual I/O Server .


Link Aggregation (on the VIO Server)

Link Aggregation is a network port aggregation technology that allows several Ethernet adapters to be aggregated together to form a single pseudo Ethernet adapter.

The main benefit of a Link Aggregation is that it has the network bandwidth of all of its adapters in a single network presence. If an adapter fails, the packets are automatically sent on the next available adapter without disruption to existing user connections. A link or adapter failure will lead to a performance degradation, but not a disruption.

802.3ad Link Aggregation do not support spanning across multiple network switches if the network switches are in a nonvirtualized state.. By using a backup adapter you can add a single additional link to the Link Aggregation, which is connected to a different Ethernet switch with the same VLAN. This single link will only be used as a backup.

(Activate Portfast on the network switches to allow faster failover time.)

Two variants of Link Aggregation are supported:
- Cisco EtherChannel (EC)
- IEEE 802.3ad Link Aggregation (LA)

While EC is a Cisco-specific implementation of adapter aggregation, LA follows the IEEE 802.3ad standard.

You could not, for example, attach a network interface en0 to ent0, as long as ent0 is a member of an EtherChannel or Link Aggregation.

Note: A Link Aggregation or EtherChannel of virtual Ethernet adapters is not supported. But you may use the Network Interface Backup feature of Link Aggregation with virtual Ethernet adapters.

A Link Aggregation with only one primary Ethernet adapter and one backup adapter is said to be operating in Network Interface Backup (NIB).

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Limitations of IEEE 802.3ad Link Aggregation, 802.1Q VLAN tagging, and SEA:

- An 802.3ad Link Aggregation device has a maximum of eight active ports and eight standby ports.
- Set speeds of each link in a 803.3ad Link Aggregation device to a common speed (for example 1g/Full duplex)
- A virtual Ethernet adapter can support up to 20 VLANS (including the Port Virtual LAN ID (PVID))
- The IEEE 802.1Q standard supports a maximum of 4,096 VLANS..
- A maximum of 16 virtual Ethernet adapters can be associated to an SEA.
- A maximum of 256 virtual Ethernet adapters can be assigned to a single virtual server (VIOS as well)

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If you plan to use 802.3ad Link Aggregation, your respective adapters must be cabled and the network switch ports must be configured for 802.3ad Link Aggregation. To create the Link Aggregation adapter use mkvdev (or cfgassist):
mkvdev -lnagg <entX> <entY> -attr mode=8023ad

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