Router having wireless type 802.11 b/g/n will have how much max speed through WAN port?

Question

1. If a router has 802.11 b/g/n like TP Link TL-WR841N then WAN port has 100Mbps speed. Right?
2. what about WAN port speed having 802.11 n like D-Link DIR-615 Wireless-N300 Router?
3. Difference between above 2 routers other than device supporting 'b' & backward compatible by 'g'. When to choose which one?
4. If WAN port is 100Mbps. And Router is getting 100Mbps(using CAT 5e or better). How much speed to expect from router & why?

Answer 1

1. The TP Link TL-WR841N has a WAN port of 100 megabit. That does not mean all routers which support 802.11n are limited to 100 megabit - the ethernet port could be gigabit. I think from your post you may not be aware that 802.11n is a WIFI speed, not an ethernet speed

2. The DIR-615 also has 100 megabit network interfaces. (Almost?) all 802.11n routers have hardware compatibility back to 802.11B and G, including this one. Performance wise, for basic router use, these routers will likely perform similarly. The DIR-WR841 is newer, so has IPV6 support and probably newer and faster chips. You can't draw too many conclusions without knowing the exact models of each (each of those routers come in many different variants).

3. As above, both above routers support B&G as well as N. I dont think you ever need to make this choice. B and G are older speeds, with B being the oldest, and pretty much no one uses it anymore. G is pretty old, but can produce useable speeds. You should be aware that N (alongside AC) is the current standard, and an AC capable router will usually be faster.

4. This question cant be easily answered, as the speed of your connection depends on the speed of the upstream connection. If its 100 megabits or more, you will be limited to 100 megabits. If its less, you will be limited to less. Really much of this depends on your ISP and their connectivity to the sites you are visiting. The most you can expect, for a typical (already compressed) file would be about 12 megabytes (100 megabits / 8). Again, this is a maximum, not an indication of throughput, which, if the ISP is providing you ADSL2 (which you get in here in NZ alongside these modems BTW), you might be lucky to get 10 megabits down.

Edit to answer Additional questions in comment -

1. Yes, both the TL-WR841N and DIR-615 are N300 (which means theoretically can do 300 megabit - although you cant that outside a lab in practice).

2. Yes, one of the purposes of dual antenna is to allow transmissions on more channels simultaneously (like listening to multiple radio stations at once), another is to cancel out interference by doing something called beam forming (look up MIMO technology for more info)

3. Your question is unclear. From a practical POV generally 802.11n is used to send signals in the 2.4 ghz band, while 802.11ac uses the 5 gig band. I believe that it is possible to have 600mbit on 802.11n, but to go higher you need 802.11AC which has more available channels/bandwidth. Most 802.11n stuff would be 150mbit or 300 mbit

4. This is slightly controversial due to the trade-offs with supporting older devices and slower speeds. The best speed will be gotten by supporting only 802.11n devices, as it has the best use of frequency. 802.11n is backwards compatible with 802.11g and 802.11b unless disabled in the router. If you have older devices which don't speak 802.11n, you will want to enable 802.11n + 802.11g, so you can run everything. If everything is 802.11n, turn off 802.11g support for slightly better performance. 802.11g can be about 73 megabit in theory - even though you don't get that in practice, a lot of Internet connections are slower then 73 megabit, so 802.11g can still be used in some cases and give you maximum internet performance (where your actual connection is a lot slower then 73 megabits). There is no advantage to having 802.11g enabled if everything is capable of speaking 802.11n.