May I ask what the server_id in dag. graphml means?

[zhangchuang-zc]

First of all, I would like to express my gratitude to the author for his excellent work and for opening up the relevant code.
May I ask what the server_id in dag. graphml corresponding to era and pm applications means? Why is there no relevant parameter in the dag corresponding to the ad application? The above issues will result in the inability to run make run_ad under the pm-wip branch.
Looking forward to your reply.