Telegram claims to have 5 data centers (DCs), referred to as DC1~5 in Telegram’s code and documentation. Among them, DC1 and DC3 are located in Miami, USA; DC2 and DC4 are in Amsterdam, Netherlands; and DC5 is in Singapore. Each account is associated with a DC upon registration and does not change with the user’s phone number or geographic location. Users cannot freely choose a DC—if connected to the wrong DC, the server returns an error message, requiring the client to connect to the correct DC associated with the account. Starting with the Frequently Down DC5 Among the 5 DCs, DC5 is particularly well-known in the Chinese Telegram community—not because it quietly serves a large number of Chinese users, but because it frequently goes down. When DC5 is down, users on DC5 cannot use Telegram, and the topic in Telegram circles often becomes, “Why is DC5 down again?” DC5 users can only wait for their constantly “reconnecting” clients to recover, then join group chats with users from other DCs to criticize DC5.…