Question regrading "one-way connectivity" the prerequisites

[haosdent]

In Prerequisites, I saw submariner mention

IP reachability between the gateway nodes. When connecting two clusters, the gateways must have at least one-way connectivity to each other on their public or private IP address and encapsulation port.

I am still confused about this prerequisite item. For example, suppose I have two gateway node

Node Name	Private IP	Public IP
A	10.0.0.1	1.1.1.1
B	10.1.0.1	2.1.1.1

Suppose A (10.0.0.1) could connect to B (2.1.1.1:4500) with Public IP and UDP port 4500 actively,
while B (10.1.0.1) could not connect to A with Public IP and UDP port 4500.
Is it possible to continue to setup submariner via Gateway Node A and Gateway Node B?