Gaming and P2P
Gamers are one of the two user types that have the most difficult time with routers. The problems stem from the conflict between the way games connect to and use the Internet and the way that NAT-based routers work. Add in the fact that there are few generally accepted standards (although Microsoft might argue with this) for how Internet based games communicate, and you may have a difficult time with online game play. And if you want to host a game server, there will be some additional hoops for you to jump through.
One thing you don't need to worrry about in gaming router selection is ping time. Any router you buy today is going to have a ping time lower than the 1 mS that ping can measure. Ping performance is always dominated by network traffic, both on your LAN and on the Internet. Quality of Service (QoS) technologies like Ubicom's Streamengine, which is used in D-Link's DGL-4100/4300 "Gaming" routers, can only prioritize traffic on your LAN.
So if you like to game and have a Bittorrent download going, QoS can help, as long as you don't try to use more bandwidth than your ISP provides. But once the packets hit the WAN side of your router, there is nothing you can do to affect the time it take for them to reach their destination.
Recommendation: The key to online gaming success is a router's flexibility in letting you open holes (ports) in its firewall. Get a product that supports as many mapped or forwarded port ranges as possible. Also look for models that support triggered mappings (this is also sometimes referred to as "Special Applications"). I also recommend you do a Google web and Google Groups search, or ask around in your favorite newsgroup or game website forum to see what works for other people.
You'll also want to choose a router that can support the large number of simultaneous connections (sessions) that are used when a game tries to find the available game servers. Unfortunately, manufacturers generally don't provide this information, so once again, you'll need to Google and ask around in gaming forums. You can also check Which Router Reigns Supreme for P2P? to see how many simultaneous connections some popular routers can handle.
Finally, make sure that your router can put one computer completely outside its firewall (called "DMZ" or "Exposed computer"). Strange as this may seem, there are some products that won't allow this, because of the security risk. But it is a helpful troubleshooting tool to see if closed ports are what is causing your online gaming problems.
NOTE: Putting your gaming machine is not where I recommend you start in order to get your game working, because this exposes the computer directly to all of the extremely nasty attacks that constantly occur on the Internet. It used to take minutes for an unprotected computer directly connected to the Internet to be compromised. But this article describes an unprotected computer being hit by the Sasser worm in eight seconds! So use this feature only as a troubleshooting tool and be sure to have up-to-date antivirus software running on any machine you put in DMZ!
File Swapping / Peer to Peer (P2P)
These folks join gamers as the most likely to not succeed in getting their favorite application to work with a router, or at least have problems in getting it work work reliably. The first reason is that P2P applications can use a large number of simultaneous connections, just as gaming apps do.
But instead of just using them for a short time while locating game servers, P2P apps use a large number of upload and download connections for long periods of time. This heavy usage can cause some routers to overheat or trigger obscure bugs in firmware, leading to flaky problems that are hard to pin down and fix.
Another problem with P2P is that it tends to be a bandwidth hog, which ISPs generally frown on. So if you are a constant P2P user and don't make any effort to limit the bandwidth you use, you can be pretty certain that your ISP will crank down your bandwidth for you.
ISPs usually don't even bother to tell you that they're doing this, or the methods of bandwidth control they are using. So you may think that something is wrong with your router when your torrents seem to slow to a crawl occasionally or even stop altogether. But in reality, it's just your ISP trying to keep you in line with their bandwidth usage policies.
Recommendation: The recommendations made for Gamers also hold for this category. But P2P users are also advised to use the bandwidth usage controls in their P2P application to stay within their ISP's bandwidth usage guidelines. You can also check Which Router Reigns Supreme for P2P? to see how many simultaneous connections some popular routers can handle. Check our Hardware Router Chart, too, so that you can choose one of the speedier products.
That's it for the overview. Now lets move on to understanding router terminology and features.