AIX Virtual Ethernet Link Status
cggibbo 270000TMUJ Comments (4) Visits (26393)
I wanted to mention a new AIX feature, available with AIX 7.1 TL3 (and 6.1 TL9) called the ‘AIX Virtual Ethernet Link Status’ capability. Previous implementations of Virtual Ethernet do not have the ability to detect loss of network connectivity.
For example, if the VIOS SEA is unavailable and VIO clients are unable to communicate with external systems on the network, the Virtual Ethernet adapter would always remain “connected” to the network via the Hypervisors virtual switch. However, in reality, the VIO client was cut off from the external network.
This could lead to a few undesirable problems, such as, a) needing to provide an IP address to ping for Etherchannel (or NIB) configurations to force a failover during a network incident, lacking the ability to auto fail-back afterwards, b) unable to determine total device failure in the VIOS and c) PowerHA fail-over capability was somewhat reduced as it was unable to monitor the external network “reach-ability”.
The AIX VEA Link Status feature provides a way to overcome the previous limitations. The new VEA device will periodically poll the VIOS/SEA using L2 packets (LLDP format). The VIOS will respond with its physical device link status. If the VIOS is down, the VIO client times out and sets the uplink status to down.
To enable this new feature you’ll need your VIO clients to run either AIX 7.1 TL3 or AIX 6.1 TL9. Your VIOS will need to be running v126.96.36.199 at a minimum (recommend 188.8.131.52). There’s no special configuration required on the VIOS/SEA to support this feature. On the VIO client, you’ll find two new device attributes that you can configure/tune. These attributes are:
Here’s some output from the lsattr and chdev commands on my test AIX 7.1 TL3 partition that show these new attributes.
# oslevel -s
# lsattr -El ent0 | grep poll
poll_uplink no Enable Uplink Poll
poll_uplink_int 1000 Time interval for Uplink Polling True
# lsattr -El ent0 -a poll_uplink
poll_uplink no Enable Uplink Polling True
# lsattr -Rl ent0 -a poll_uplink
# lsattr -Rl ent0 -a poll_uplink_int
# ifconfig en0 down detach
# chdev -l ent0 -a poll_uplink=yes
# chdev -l en0 -a state=up
# mkdev -l inet0
# ifconfig en0
inet 10.1.5.9 netmask 0xffffff00 broadcast 10.1.5.255
tcp_sendspace 262144 tcp_recvspace 262144 rfc1323 1
Right now, the entstat command doesn’t report the bridge (VIOS/SEA) status. However, this APAR (IV55505) indicates that this feature is coming.
This feature is still considered “new” but I’m very interested to see how this will integrate with PowerHA in the future. Perhaps the use of “Single Adapter” configurations with PowerHA will become more robust (allowing PowerHA to track and respond to network events)...…and possibly more prevalent. You can find more information on this feature here: