Netgear FS105 - Uplink, what does it do?

[zcacogp]

Chaps,

Some of you will have followed my "I'm setting up wireless BB on the cheap" saga on here. Many thanks for your input to date.

The last bit of the jigsaw has finally arrived - a Netgear FS105 switch. (Cost - £3.02p on ebay). Like this: www.netgear.co.uk/unmanaged_ethernet_switch_fs105.php.

This is being plugged into a BB modem/Router (BT Voyager 205), and a desktop computer, and a wireless access point - a Netgear ME102 (like this: www.netgear.com/products/details/ME102.php).

Now, the switch has an "Auto Uplink" feature. It has 5 ports on the front of it, and one of them is controlled by a little button, which can be set to "Normal" or "Uplink". I have the router plugged into this port, and the desktop and the wirelss access point plugged into two of the others. (This is the only plugging-in arrangement I have tried - it may work with other arrangements.)

And it will only work when the button is set to "Uplink", not when it is set to "Normal". Why is this, and what does the "Auto Uplink" setting mean/do? (When it is set to "Uplink", as it is now, it all works tikketty and boo.)

And, one last question. My machines are resolving to addresses in the 192.168.1.x domain. I know that the router allocates ...1 (i.e. 192.168.1.1) to the ethernet port on it, and ...2 to the USB port on it (which I am not using.) The desktop claims to be ...3, and the laptop ...7. Which bit of this setup is handing out the IP addresses? (Sorry if I haven't give you enough information there - do ask if you need to know more.)

Thanks in advance for your help ...


Oli.

[bogie]

the uplink feature changes the port from being a straight wired cat 5 to a crossover...not needed that much these days as most devices support auto detect of this and do it automatically

Its your router thats giving out the IP addresses......

dumb question though...but why have you bought 3 boxes to do the job of one? A £50 NETGEAR DG834G would do everything you have now, and more, even better?

[tinman0]

zcacogp said:

And it will only work when the button is set to "Uplink", not when it is set to "Normal". Why is this, and what does the "Auto Uplink" setting mean/do? (When it is set to "Uplink", as it is now, it all works tikketty and boo.)

if you are saying that the router is plugged into the uplink port in uplink mode and only works that way - the answer is very simple and is a legacy thing that is fundamentally wrong.

some routers have a ethernet port that is not a standard ethernet port, its actually presented as a port you would find on switch or a hub, which is a crossed port. you set uplink because you need to reverse the signal on cable to make it all work.

the reason for this is is because some (many) early home routers were only ever meant to be used with one computer. the idea of a home "network" was alien so they supplied a cross port as standard, allowing the user to use a normal straight RJ45 cable. life is easy.

until - the user decides to break out the router to a switch/hub and use multiple machines on the network. at this point you have this very odd dilema which you solved.

[tinman0]

zcacogp said:

Which bit of this setup is handing out the IP addresses? (Sorry if I haven't give you enough information there - do ask if you need to know more.)

the router.

in your router set up there will an allocation table for its built in DHCP server. the DHCP server gives out the addresses. essentially, when the machine(s) first boot up they send a broadcast on their ethernet which is an invitation for any DHCP to send them some information. A responding DHCP server sends the IP address info and bobs your uncle. the DHCP server then keeps a table of who its given what ip address to.

[zcacogp]

Chaps,

Thanks for the answers ... therefore, if I was to use a cross-over cable from the router to the switch, then I would need to set the button to "Normal" rather than "Uplink"? I understand the difference between straight and cross-over network cables, but don't quite understand the different situations you would use them in.

However, you are right, when I was running one machine from the router via the ethernet port, it would run using a straight cable.

You all say that the router is handing out IP addresses. I didn't think it had this capability - I thought it would only resolve to ...1 and ...2 on the two ports, but not that it would hand out addresses beyond this. However, it sounds I am wrong! Why would a router which was not expected to be used with a home network (so much so that it was designed with a cross-ethernet port) also be designed with the ability to hand out IP addresses on a network?

bogie said:

dumb question though...but why have you bought 3 boxes to do the job of one? A £50 NETGEAR DG834G would do everything you have now, and more, even better?

Not a dumb question - I am a cheapskate! If the DG834G is the all-in-one modem/router/wireless thing, I found them to be nearer £80. And I already had the modem/router, the switch was £3, the wireless thingie £8.50p. And I wanted to learn about this sort of thing.

Why would the DG834G have been better?

Thanks again for the answers,


Oli.

[tinman0]

zcacogp said:

You all say that the router is handing out IP addresses. I didn't think it had this capability - I thought it would only resolve to ...1 and ...2 on the two ports, but not that it would hand out addresses beyond this. However, it sounds I am wrong! Why would a router which was not expected to be used with a home network (so much so that it was designed with a cross-ethernet port) also be designed with the ability to hand out IP addresses on a network?

generally they put a dhcp server on to make the solution easier for users and as most xp boxes (at least) come with their ethernet set to dhcp anyway. by adding a dhcp server 90% of issues of getting the router and the pc to talk to each other probably dissappear as soon as they see each other.

[bogie]

an all in one box is easier to manage, faster wireless, faster ADSL (up to 24Mbps if you can get it) ....but of course if you just want cheap and working, and only have 1Mbps connection etc then what you have will do the job just fine

[malman]

zcacogp said:

Chaps, You all say that the router is handing out IP addresses. I didn't think it had this capability - I thought it would only resolve to ...1 and ...2 on the two ports, but not that it would hand out addresses beyond this. However, it sounds I am wrong! Why would a router which was not expected to be used with a home network (so much so that it was designed with a cross-ethernet port) also be designed with the ability to hand out IP addresses on a network?

That covers the two ports on the router but your PC still needs an IP so if the router has DHCP then that gives the address to the PC. Nothing wrong with DHCP giving out just one address. If the user then figures out crossover cables etc then its also handy for giving out more addreses to all the devices attached that require them.

[redgta]

zcacogp said:

Chaps, ... therefore, if I was to use a cross-over cable from the router to the switch, then I would need to set the button to "Normal" rather than "Uplink"? I understand the difference between straight and cross-over network cables, but don't quite understand the different situations you would use them in. Oli.

All the uplink switch does is reverse the internal wiring between the transmit and receive pins. So if you us a cross over cable then it is the cable that is doing the cross over. The point of it is so that you could connect two hubs/switches together when all you have to hand is a bunch of normal straight through cables. The trouble with cross over cables is that after they are made, it is hard to spot them in a pile of cables. As previously said... modern kit does not have an uplink port becuase the device is smart enough to know what it is talking to and does the required cross over automatically. In a network configuration like we have I can tell you live is much simpler that way.

Cheers, Red.

[aldi]

bogie said:

an all in one box is easier to manage, faster wireless, faster ADSL (up to 24Mbps if you can get it) ....but of course if you just want cheap and working, and only have 1Mbps connection etc then what you have will do the job just fine

Easier to manage - a good learning experience
Faster wireless - how?? Plus you're less constrained about where the access point can go cause cat5 is less bothered by length than ADSL is.
Faster ADSL - if you can get and want ADSL2 yes, but you can't so its kind of a moot point

Allthough i am slightly biased, i'm typing this through my ebay special wireless access point, cheapie network switch and home made linux based router

[bogie]

faster wireless - 802.11g rather than 802.11b - not an issue for surfing the web, but if you have multiple devices in the home then you soon run out of steam with 11Mbps, which is a real 5Mbps at best, which soon tails off to sub 1Mbps in the next room etc......

[zcacogp]

bogie said:

faster wireless - 802.11g rather than 802.11b - not an issue for surfing the web, but if you have multiple devices in the home then you soon run out of steam with 11Mbps, which is a real 5Mbps at best, which soon tails off to sub 1Mbps in the next room etc......

Bogie,

Good point there.

I am happy with a home-grown network as I am learning heaps by doing it (hey, I wouldn't even knomw what a cross-over cable was if I hadn't tried this!), I am saving a fair bit of beer money, I have more flashing lights on more boxes on my desk (which always impresses me and amuses the cat - don't know whether it impresses/amuses anyone else) and I can talk in an intelligible way about things that I don't know firk all about! Must be good!

And, on a serious note, my much beloved IBM thinkpad only has b-spec wireless, not g-spec. So a faster wotsit wouldn't make any difference.

Didn't know that the speed tailed off as you moved away. I can get "Excellent" reception in the same room, and it only ever drops as low as "Good" at the other extreme of the house (v. solidly built large victorian terrace.) Admittedly it goes down to "Poor" in the coal cellar, but I don't tend to take the computer there much ... Does this mean that I am losing speed as the signal quality deterioraites? If so, how much by? And why is 11mbps a real 5mbps at best? (I have 4mbps broadband, so don't really want the speed to drop much below this.)


Oli.

[bogie]

its complicated...will try to explain in laymans terms (try google also!)....basically different protocols are more efficient at transporting data than others.

the concept that you have to get into your head is that if you want to transport say a 500Kb Word document there is more than 500Kb of data sent across the network. This is due to the data being 'wrapped-up' in other information required for the data to get from a-b correctly.

Some protocols require more information attaching to the data than others.

Another concept to grasp - the data transmission rate...the figures you see mentioned everywhere like 100Mbps ethernet and 54Mbps wireless is different to the data THROUGHPUT. The transmission rate is how fast the bits are hitting the transmission media - whether thats wires or radio waves. The throughput is what the end user sees - what you are interested in...how long does it take to transmit my 500Kb file (you dont see all the extra info being tagged onto it to transmit it)

Heres some examples - you can read about the rest elsewhere

generally ethernet is around 90% efficient i.e. 100Mbps data rate gives 90Mbps of real data throughput

802.11 wireless is like wireless ethernet, so imagine taking your data, then adding on what you need to transmit it over ethernet, then add some more stuff on (802.11 info,encryption etc) and you have even more data transmitted to transport the same 500Kb file.

so 802.11 is around 45-55% efficient - so for a data transmission rate of 11Mbps you will get a real throughput of around 5Mbps

Powerline (Homeplug) networking is even worse - 14Mbps equates to a real 3-4Mbps and the new 85Mbps 'Turbo' Powerline gives a real throughput of around 15Mbps

Right - next bit, you are using radio waves to transmit your data, radio waves attenuate (get weaker) the further you go away from the antenna. There is a legal limit for RF output that everyone builds their products to. 802.11 is designed to fall back in data rate the further you get away

For 802.11b you will see at best it will connect at 11Mbps at worst 1Mbps, then it will drop off altogether (half all the above for real throughput again)

Ignore the Windows utility for reporting signal strength - its poo...you really want to the use the manufacturers wi-fi card utility (usually more reliable/more detail) or use a top quality card and custom wireless sniffer software that are calibrated to work together otherwise its worthless info.

What you can measure at home easiest (ignoring signal strength) is throughput at a give range. Just try downloading the same file from a local server/another PC over the wireless network and time it/watch the transfer rate in Windows - that will give you some indication to how much real throughput you are getting and if your wireless network is becoming a bottleneck to your 4Mbps internet pipe

ok - now you can goto www.howstuffworks.com and read some more

ps - when you are playing with this stuff be careful not to mix up your bits and bytes...its easy to get confused if you are not sure what you are looking at - your internet connection is 4Mbps (megabits per second) you may see Windows reporting KB/s in places which is KiloBytes not Kilobits etc....confuses newbies sometimes !

[zcacogp]

bogie said:

... lots of useful, interesting stuff ...

Bogie, Thanks. I didn't realise that the transmission protocols over wireless were so inefficient. I presume that running security keys is going to make things worse still ...

The signal drop off as you get further away from the base point - yes, OK. However, when does the weaker signal switch down to 1mbps from 10 (or 11)? for instance, I am in the kitchen on a wireless lappie while I write this, and the signal strength is "Excellent", and the speed is listed at 11mbps. However, if this was to drop down to "good" and then "poor", I think that it still lists as 11Mbps. Is this really the case, or is the system telling porkies?

I'll go to www.howstuffworks.com and have a read there - thanks for the suggestion.

Chaps, all, thanks very much for your time. It's appreciated! (Look, I posted a thread asking about what a button on my new switch does, and ended up with a very interesting lesson in wireless data transmission! What could be better!)


Oli.