SNAT not working from Non-NAPT switch node

ISSUE : The SNAT implementation in the ODL chooses a NAPT switch among the control and compute nodes. In this NAPT switch node only the table 21 flows are written and in the non-NAPT switch these flows are absent.

Due to this in the SNAT scenario when we initiate communication from the non-napt switch, it fails.

This is due to the table 47 and table 21(few flows) flows that are absent in the non-napt switch node.

This issue is seen in both the controller and conntrack mode, but the behavior is different in both these nodes.

IN Controller Mode - The SNAT scenario when we initiate communication from the non-napt switch, it fails during the first attempt.Then when we try from the napt switch node SNAT works perfectly fine,

After this step when we try to communicate from the other VM (non-napt switch node) it succeeds.

This is due to the table 47 and table 21(few flows) flows that are absent in the non-napt switch node.

Once we establish the communication from the VM in the napt switch node, the table 21 flow occurs in the non-napt switch node.

IN Conntrack Mode - From the non-napt switch SNAT fails completely , even after trying SNAT from the napt switch node VM. SNAT from the non-napt switch fails.