Controlling the priority of certain types of network traffic is an excellent, often overlooked feature of modern routers. You don't want your video stream to have major glitches because someone else in the household is downloading the biggest collection of MP3 files in P2P history, right? Get Quality of Service (QoS) configured correctly and the network may be able to take care of this on its own.
A lot of 802.11-certified equipment comes with some basic QoS functionality in the form of Wi-Fi Multimedia (WMM). If your router and network adaptors are WMM-certified, they have the feature turned on and your app supports WMM, you're in business.
The program adds QoS details to its packets that say, 'I'm important, me first', so the router prioritises them ahead of other traffic. There are problems with this scheme, though. Not enough apps support WMM to make it really useful, and while its automatic nature cuts network management hassles, it doesn't give you enough control.
For that you need QoS features in the router, so it's worth checking to see what's on offer. Billion routers such as the BiPAC 7800N support DSCP (Differentiated Services Code Point) marking, a scheme where sources tag their network packets with information about what they are. If your apps do this then you'll be able to do things like assign a guaranteed level of traffic to media streaming, and a maximum level to P2P apps.
You can apply these rules to particular ports, internal or external IP address ranges or even a set timeframe, maybe restricting P2P to 10 per cent traffic during the day but allowing it 90 per cent between 1am and 8am.
Linksys routers are generally very configurable, too. For instance, the WRT610N can prioritise traffic by MAC address as well as application or Ethernet port, so you can ensure that a particular network device always gets the same level of priority, whatever it's doing.
Alternatively, if tweaking all that sounds too much like hard work, you might prefer D-Link's solution. Many of its routers include a simple technology ('Wireless Intelligent Stream Handling') that will look for media streams and then automatically prioritise them.
Which QoS solution is best for you will depend on your setup and circumstances, but do take the time to explore what a particular router offers before you buy. Good QoS settings can make a great deal of difference to a busy network.
Speeding into action
Upgrading to an 802.11n router isn't a magic bullet. It's unlikely to have a huge impact on your wireless range (although it should improve performance, even at the outer edges of your network). It won't make 802.11g devices any faster, either. Also note that to get the most out of it you'll need 802.11n clients elsewhere (however, with prices starting at under £10, this needn't be expensive).
Still, once you're properly set up, there are all kinds of benefits on offer. Significantly better speeds; improved WPA2 security; the ability to avoid interference if you've got a 5GHz model; built-in automatic prioritisation of the most important web traffic; bonus extras, such as easy network storage or printer sharing; and a host of other features that come automatically with up-to-date firmware.
So, which router should you choose? Our preference would be a dual-band, dual-radio model, especially if you live in close proximity to other networks: escaping their interference will save you hassle.
The dual-band 802.11n router market is fairly immature, though, and not every manufacturer has yet got the new tech performing at its best.
If interference isn't a problem with your G network, don't feel you have to do dual-band right now. A single-band N router will deliver plenty of benefits at a low price, and you can take advantage of the greater range of dual-band products that will be on offer when you do decide to upgrade.