Automatic Behaviour

The protocol has several rules a client must follow to keep a search alive. The SDK follows them for you, so you don't write code for any of this.

What the SDK does for you

• A ticket per attempt. Every connection attempt, including each reconnect, asks your ticket provider for a new ticket, because tickets are single-use and expire after 5 minutes. See Generate a Ticket.

• Ping checks. For ping-based game modes, the server sends a PING and the SDK replies immediately. The server measures round-trip time from its own clock, so the SDK needs to answer quickly and has nothing else to do.

• Heartbeats. A heartbeat is sent every 45 seconds while searching, so the search doesn't expire. See Heartbeats & Disconnects.

• Reconnects. If the connection drops mid-search, the SDK reconnects with a new ticket and sends begin_search again for the same game mode. Within about 30 seconds of the drop, the server resumes the held search with its original search time, so the player doesn't lose their place.

• Backoff. Retries wait 1 second, then double up to a 16-second cap. Once a reconnected connection has stayed up for a full heartbeat interval, the next drop starts again from 1 second. Retries continue until you call CancelSearchAsync or CloseAsync.

• Recovering from a stale pong. If the server reports that a pong didn't match a pending ping check (STALE_PONG), the SDK re-sends begin_search.

• Party members. A party member never calls BeginSearchAsync. The SDK starts their heartbeats when SEARCH_STARTED arrives, and answers a ping check with the party's game mode.

It doesn't reconnect a connection opened with ConnectAsync: the server removes a disconnected player from their party, so there is nothing to resume. The state becomes Closed and Party is cleared. See Parties.

It doesn't reconnect after a terminal error or a superseded search, because the server ended those on purpose. See Error Handling and Events & States.

Tuning

Pass a MatchmakingClientOptions to Initialize to change the defaults:

_matchmaking.Initialize(tickets, new MatchmakingClientOptions
{
    HeartbeatInterval = TimeSpan.FromSeconds(30),
    InitialReconnectDelay = TimeSpan.FromSeconds(2),
    MaxReconnectDelay = TimeSpan.FromSeconds(30),
    MaxReconnectAttempts = 5,   // default: null, which retries until cancelled
});

The backoff policy is the SDK's own choice. The protocol only requires that clients back off between attempts.

Next

Once a match is made, your game still needs somewhere to play it: After a Match.