Pod-to-pod communication within the same node goes through the bridge by default. Let's say we have two pods that have their own network namespaces. When pod 1 wants to talk to pod 2, the packet passes through pod 1's namespace to the corresponding veth pair, vethXXXX, and eventually goes to the bridge. The bridge then broadcasts the destination IP to help the packet find its way. vethYYYY responds with the broadcasts. The packet then arrives at pod 2:

Now that we know how the packet travels in a single node, we will move on and talk about how traffic gets routed when the pods are in different nodes.