IWatkins

Hi All,

Need some advice here. Scenario:

Got a 100mBit ethernet LAN. Lots of machines on it. I want to add two more machines to it. OK, no problem. Machine 1 is going to accept (via FTP) a feed of files from a larger system on the LAN. These files are going to be the order of approx. 60Mb a day. Again, no problem. These 60Mb of files are going to be processed on machine one and will generate some huge files, something in the order of just over 200Gb a day (which might rise to 400Gb). Now I need to get them to machine 2. Machine 2 will then allow access to these files via a web service that will supply tiny amounts of data from these huge files to any client on the main LAN.

What I've been told is that I am simply not allowed to to push that amount of data over the main LAN. Fair enough

So what I thought I would do is put two network cards in both machines. Card one would be your normal 100MBit card, the second card being a GBit one. So machine one would use card 1 to talk to the LAN, it would then use card 2 to talk to a switch thingy . Machine 2 would use the 100MBit card to talk to the LAN and card 2 (the GBit one) to talk to the switch.

This way all the files being moved between machine 1 and machine 2 would a) have fast commes and b) won't impact on the LAN.

Now, I've never tried this, nor played with anything faster than 100MBit networking (well, not on PCs anyway). Is this feasable/doable ? And if so, how would you configure the 'mini' network. Also, any advice you might have.

Hope that makes sense.

Cheers

Ian

WillieF

No I don't see a problem with this I can think of other ways of doing it HOWEVER there would only be any point if there was more than 2 machines.

HHxx

Sounds fine to me hardware wise.

But what about the software?

carl

This is just getting your PC to act as a router. Actually I don't see the need for the switch: can't you just back-to-back GigE between the two machines?

All you need to do is configure the routing tables on machine 1 to say:
machine 2's subnet: over here down this GigE link
everything else: over there down that FE link

and the converse for machine 1's routing tables.

It matters little whether these are Unix or Win boxes, as I can't tell you the commands for either. If they were Cisco (or some other) routers I could tell you.

dsmith

Network wise it will be fine

Make sure you use a private subnet on the inter-connect LAN that isn't in use in your organisation or anything you want to connect to on the internet. RFC1918 192.168.x.x adresses would be ideal (providing they're not in use already)

On Machine B (the receiver) ensure the ftp server (is the transfer FTP?) is bound to the interconnect interface.

When Machine A attempts to connect via the IP address, as that address is part of a directly connected LAN (the interconnect) it will default to the right interface.

To be honest 100 Mb full-duplex between the servers would probably be enough. Its probably best to try several concurrent transfers to maximise the transfer rate.

If its just two machines then forget the switch and cable back to back - whether its Cat 5 or Fibre.

Deano

dsmith

Oh and IMHO the last thing you want the boxes to do is try and route between their 2 interfaces - so ensure IP forwarding is off.

If its just the two devices on the inter-connect LAN there is no need for any static routes.

- Unless you want some remote management to ping the interconnect interfaces to check availability etc - then you would need to enable IP forwarding and give the next hop routers the right statics etc.

Deano

carl

...if you want IP forwarding ON, then you'll need some access lists (can't have the other LAN users using your nice fast GigE segment).

IWatkins

Nice one guys, thanks for all that.

OK, so it is all doable then. Lovely.

Yes, reason I said having a switch in there is that there may the need for several boxes acting as machine 1 and several more boxes acting as machine two. As as they will be put in as pairs, I will look at dropping the switch and just do back-toback cabling.

The reason we are looking at GBit network is that although the throughput is going to be 200Gb to 400Gb at first, if it works well, we are looking at 1 - 2 Tb a day once operational. Of course, this will be met with some big servers, and done properly by someone who knows what they are doing.

HHxx
Sounds fine to me hardware wise. But what about the software?

That is where I come in It is basically a big numerical weather model system on machine 1 and machine 2 will be responsible for being the web service host with a load of that XML malarky.

Cheers

Ian

dsmith

Mind you - Any excuse to over spec the hardware shouldn't be ignored by self respecting techies so probably best to budget for the biggest gig switch you can find....

HHxx

Trust you Deano

Andy Hall

You will need a crossover cable somewhere if youre not using a switch, let me know if you want one.

Andy

carl

Is this GigE over copper or fibre (if the latter, you don't need a crossover cable obviously as you just swap the Tx and Rx fibres)?

Andy Hall

I was assuming copper, If you are using a duplex SC connector you will have to snap the retainer, unless you buy a crossover lead (or a simplex one to start with.

Andy

IWatkins

Well the GigE segement is totally under our control so we can use what we like for the connections. Obviously we will be looking to the future where the whole system will end up in a rack in the main computer hall (with managed support), but in the meantime it is a free for all

dsmith
Mind you - Any excuse to over spec the hardware shouldn't be ignored by self respecting techies so probably best to budget for the biggest gig switch you can find....

Exactly !!

Cheers

Ian