IBM Support

What is the difference between largesend and jumbo frame?

Question & Answer


Question

I am configuring VIO Servers and AIX VIO Clients on Power system. There are many network attributes realated to laregsend and jumbo frame such as largesend, large_send, mtu_bypass, jumbo_frame, use_jumbo_frame. I am confused about these attributes. I want to understand how largesend and jumbo_frame work and what is the difference between two.

Answer







In case 1, Messages are segmented to MTU size 1500 by TCP Kernel stack in AIX.




In case 2, Messages are segmented to MTU size 1500 by Real Ethernet Adapter.




In case 3, Messages are segmented to MTU size 9000 by TCP Kernel stack in AIX.



In case 4, Messages are segmented to MTU size 9000 by Real Ethernet Adapter.

Conclusions:
- largesend and jumbo frame does two different actions. These actions are mutually independent.
- largesend decides who does the segmentation.
- jumbo frame decides the size of the segmented packet that goes on the wire.

Authors: Darshan Patel, Perry Smith, Saania Khanna

Feedback: aix_feedback@wwpdl.vnet.ibm.com

[{"Product":{"code":"SWG10","label":"AIX"},"Business Unit":{"code":"BU009","label":"Systems - Server"},"Component":"Network communications","Platform":[{"code":"PF002","label":"AIX"}],"Version":"Version Independent","Edition":"Standard"}]

Document Information

Modified date:
17 June 2018

UID

isg3T1025713