[FAQ] Using two routers together/ Extending Wi-Fi

AK 47

Hi all, I posted the following in the thread I started (here,) but it didn't get a response, so I thought I might post it here. I really need some help!

Thanks in anticipation.

mickevh

I have changed the BT Home Hub 3 IP address to 10.0.1.2 (is this correct?), but I get the error message: Invalid IP setting - These IP settings are not valid on the BT Home Hub.


It's academic if HH3 won't let you use a 10.X.Y.Z address, but this needs to be outside the DHCP range of the AirPort  - 10.0.1.2 is within the Airport's DHCP range.

tom 2000

I actually moved the Homeplug and Router combo to a different part of the house. I've noticed the Internet connection can be lost if a vacuum cleaner or ome other appliance is on but the connection always resets itself. So I deduce it was some sort of homeplug problem. I bought a tp link router and set it up as what I think is a wireless repeater. Works okay but the tp link does not have the wireless grunt of the Range Max limiting access in my outside stables. That's despite using an upgraded ariel. I might try the homeplug and Netgear router in the stable block and see if that works.
The tp link was easy to set up and in fact I have another still in the box that I was considering using to wirelessly enable the Skybox but am concerned that they are repeaters and using one or two in the house will reduce the effective  speed about the place. Network cables are so not possible. I guess I am really asking about the effect of using very convenient easy set up tp link wireless repeaters, if that is the correct term.

mickevh

"Repeaters" at least halve your wi-fi bandwidth. It's because the original transmission and the "repeats" cannot be transmitted at the same time.

I'm not sure if this is compounded by each additional repeaters (ie, two repeaters == 1/4 throughput, 3 repeaters == 1/8 throughput, etc.) it depends somewhat on how they work.

However, I can't help but think that the more repeaters you have, the more wi-fi throughput will be affected.

If you want to do something clever with antenna's, you could look into setting up a point-to-point link with some directional antennas (a couple of yagis or parabolics) but I suspect were talking about more serious money here.

tom 2000

At what point does this noticeably affect performance? Relative to the speed needed to stream a movie file from Sky in near real time?

mickevh

I think there are too many "it depends" factors for me to adequately answer that question. To give a flavour, it depends on... the bandwidth requirement of the file, the amount of "other" traffic on your wi-fi, how much interference there is in your locale (causing packet loss & needing retransmits.)

You may just have to suck and and see. Perhaps it would also be worth asking in the "Sky" forum and see if anyone there has similar experience.

tom 2000

Do they halve bandwidth just by being there or only when active? If only the latter I think I could live with it as they would only be used for specific file downloads and I would have some control as to when that actually happens.

mickevh

The way a repeater works is that it listens out for any wi-fi transmissions, copies them, waits the the airwaves to go dead, then broadcasts (repeats) a copy of the original transmission.

In a wi-fi LAN only one thing at a time can transmit. Thus, the original transmission and the "repeat" cannot occur at the same time, therefore each transmission take twice as long.

This is Top Gear maths but...

Imagine I send a 1000 bit packet and it takes one second. Turn on a repeater and I now send those 1000 bits twice (once for the original and once for the repeat.) They cannot occur at the same time, so it now takes 2 seconds to complete the transfer. And 1000 / 2 == 500, so my effective "throughput" has halved.

It's possible that repeaters are clever enough to "know" what being repeated through them and what's not (ie which workstations they are working for) but I simply don't know. I'd tend to think not - it would make them more complex (read more costly) to implement - but I'd need to obtain one and stick a protocol analyser on them to see.

tom 2000

Suck it and see then.

paperclip810

Hi everyone,

I've read through this thread and can't quite see a solution that fits our situation so I'm hoping you all might be able to offer some guidance.  Apologies if I've missed something while reading these pages.

Our set up is:
Small living room (front of house): BT Home Hub 3 connected to outside (main) connection with Wi-Fi network for main house. Powerline adapter connected to BT Home Hub.
Main living room (back of house): PS3 (Wi-fi connection), X-Box360 (Wi-fi connection), Sky HD box (Ethernet cable to second powerline adapter).
Upstairs: Desktop PC connected with wi-fi.

There is excellent wi-fi reception throughout the house.  However, we have a brick built 'games room' at the bottom of the garden (approximately 20 metres from back of house, and 30 metres from BT Home Hub location.  This room has no wi-fi signal.  

We can't move the BT Home Hub due to layout and connection points.  At the moment, I don't know if the games room is on the same electrical circuit as the main house.  What are our options for extending the signal to the games room?  At the moment, I'm thinking of another homeplug in the games room (circuitry permitting) with a wireless router connected, but there's probably an easier (and cheaper way of doing this).  

76MB internet from BT - we don't need huge bandwidth in the games room but enough to stream music or iPlayer etc would be excellent.

Thanks in advance for any help you can offer - if you need more info, please let me know and I'll see what I can provide...