ok, here is a light networking reply, most of which you probably all know anyways.
what we usually call a router (and there has been a lot of cross reference between routers and switches) is something that can 'route' traffic intelligently. you can call them intelligent switches/smart switches/etc. They make intelligent decisions on where to send the traffic, based on a set of rules/tables/whatever way they're setup. a switch is generally thought of as 'less intelligent' then a router, but once again, people cross referance the two a lot in the field.
a 'hub' (which some still cross reference to routers and switches.) is basically just a connecting point. like the hub in a spoked wheel. a hub usually isn't intelligent at all, or often very little, at most rudimentary logic. and it sends it data all over the place and leaves it up to whatever sees it to determine if it should get it or not.
Often when you hook a router up a isp's modem for instance, the router will have rudimentary or even a quite complex firewall, or routing algorithm. Often this will mean it will setup permissions to automatically ignore all information not meant to come to your system in the first place. Usually their IPtables are meant to only deal with one IP. on some routers you can of course re-write them yourself and change that. On some you can disable it altogether, and on some you can allow complete passthrough. Furthermore, your router will also often have the ability to act as a DHCP server, which can assign IP's to your computers as well. this allows it to do NAT, and for you to setup a LAN (a local area network-ie only inside your house or local area not the internet.) if you are doing this, your router is giving each of your computers a separate ip. typically unless it is changed inside the configuration, these ip's will be something like 192.168.X.1,2,3 or something similar. If you do a 'ipconfig /all' at a command prompt, to each of your systems, and thats what you see then it's highly possibly your router is assigning the ip's, not your isp. If you get something that is within the IP block of your isp like 68.x.x.1,2,3 then your probably getting them from your isp. (the above 68.x.x.1.2.3 is only a example your isp will more then likely assign different ips.) anyways I digress slightly.
How you get 'dynamic IPS' is through a DHCP server. your pc sends a request, it responds and give you a ip it has available. your isp's modem will only allow a certain number of these. When you order extra ip's from your isp, they 'push' or upload a config file to the modem which tells it to allow more.
you can have multiple IP's of course from your ISP. What that is, is the service provider's equipment/ modem, routes and accepts data packet from all the ip's that you have been assigned to. It will not 'necessarily' increase your speed or give you any extra benefits hardly compared to having your own router that allows dhcp and lan. Your bottleneck (the part that will slow everything down.) will be your isp's modem and the data it allows through it. That data will not increase or decrease more then likely if you have 1 ip or 5., even though it will most definitely if you have two modems and load balance them, but thats a different story.
There are of course exceptions to this, but chances are your not one of them. this is why they're called exceptions. For one, your modem is actually restricted by your isp on purpose as to the speed it will allow. it is possible a isp could potentially uncap or unthrottle your modem to allow higher throughput if you pay for a extra IP. I have only heard others claim their 'isp' did this, I have never actually known a 'isp' to do it.
And if you have a router setup to get a IP from your isp's modem. it will use dhcp, get 'one' ip and thats it. unless you have a router which allows multiple wan (Wide area network- ie the internet) side ips. They exist, but you probably don't have one. the only way to actually use the multiple ip's is to dumb down your router/switch, put it in by-pass mode or to use a hub, in which case, the router or hub isn't doing anything really. each pc is sending a dhcp request through the hub/dumb router to the modem and getting a individual ip back. If there is no 'routing' going on, then each packet of information is sent through each wire to all the computers, creating way more traffic then there should be and slowing stuff down, until one computers nic says 'hey thats mine' and takes it. it's basically the same as if you shouted out in the middle of the room that you might of just caught a STD from this chick instead of talking directly to your friend right next to you.
anyways, good luck.
How can set my router to give each computer a different ip?
