Following the likes of Modern Warfare 2, Aliens vs. Predator, and RAGE, Ubisoft mentioned in a Q&A session that Splinter Cell: Conviction will not support dedicated servers.

Will there be a dedicated server for Splinter PC?

No, there is no dedicated server mode.

So naturally, you might be wondering about the matchmaking, which Ubisoft also addressed in the Q&A.

How does the matchmaking work exactly? (PC and Xbox)

The matchmaking system attempts to put two players together that are looking for the same type of match based on the selected Map, Difficulty, Language and Ping. If no good matches are found, the player can create a match and wait for someone to connect. Players can also create private matches. Additionally, in the event where we don’t find an exact match to your preferences, we gradually and automatically start widening the search parameters until we find the closest best match to what you were looking for. There are no match listings in Conviction, you are matched with the best possible person out there.

Conviction will have a lobby system as well where players can negotiate match settings.