How to troubleshoot or enable Jumbo Frame in VIOS physical adapter ?

Answer :

Ethernet packet of payload size more than 1500 bytes is refereed as Jumbo Frame. To debug the VIOS or enable the Jumbo Frame in physical adapter of VIOS follow the below steps.

# ifconfig en333 down detach
# chdev -l ent333 -a jumbo_frames=yes
ent333 changed
# chdev -l en333 -a mtu=9000
en333 changed

After enabling Jumbo Frame and mtu size on physical adapter. Perform smit mktcpip and Start the network of en333 adapter.

#smit mktcpip

Then check the netstat -in command

# netstat -in
Name   Mtu   
en333    9000  
en333    9000

If everything is OK so perform ping test on the target, target VIOS or LPAR should have already been enabled with Jumbo Frames prior to ping.

Success scenario 
# ping -s 9000 target
3 packets transmitted, 3 packets received, 0% packet loss

Failure scenario
# ping -s 9000 target
2 packets transmitted, 0 packets received, 100% packet loss

If failed to ping either ask network admin to configure Jumbo Frame on network switch or make sure target ip should also be having Jumbo Frame configured else it will fail.

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