A Crash Course on Network Bandwidth Metrics?

Kind of Blue asks: "I work for a small software development company in India, providing development services for a company in UK. We connect to the UK client through VPN; and our correct staff strength is around 13. We are going in for a major upgrade in our internet connection — and owing to the size of the firm, cannot afford the services of a networking expert/consultant. Hence I, a layman, have been asked to look into the matter and decide on the ISP and the bandwidth. I have a vague idea about the required bandwidth — it must be around 512 kbps(remember, it's India I am talking about!) and must be a persistent connection, since we use source control softwares connecting to servers in the UK. There doesn't seem to be a 'networking for dummies' kind of resource on the web. No one seems to talk of network metrics anywhere. So, can Slashdot give me a crash course in what I need to know?" "Our present ISP gives us a DSL connection of 512 kbps on 1:4 sharing. There are frequent disconnections; and hence loss of work while code check-ins. As we are increasing in strength, I am also looking at more bandwidth. But what bamboozles me is how are these things measured? Will I get a better bandwidth if I take a 512 leased line on 1:2 sharing? When the staff doubles, should I upgrade to a 512 connection on 1:1 sharing or must I take 1 Mbps on 1:4 sharing?(There's a huge price gap between the 2 here in India) In any case, how does one decide the optimum bandwidth required for a bunch of 15 developers on VPN and Source control?"

Comments

Measure twice, cut once

[edmudama]

it must be around 512 kbps(remember, it's India I am talking about!) and must be a persistent connection, since we use source control softwares connecting to servers in the UK.

Have you actually measured how much bandwidth your source control software application consumes? To me that'd be the very first step, before you look into upgrading from one voodoo number to another. Real data is very often the key to good decisions.

Re:Measure twice, cut once

[Kesch]

Stop calling my numbers voodoo! Libraries of Congress/Fornight is a respected measurment for bandwith and I know many people who like to have their ping times displayed as multiples of the time it takes light to travel from NY to LA (assuming a vacuum of course).

Re:Measure twice, cut once

[Kesch]

PS, in case you were wondering I calculated it out. My current ping to google is 6.73 trips from LA to NY at the speed of light.

Re:Measure twice, cut once

[Bastian]

Keep in mind - [i]bandwidth is not the same thing as speed.[/i] If your transfers are small enough that you're never really filling the pipe (as is probably the case if most of what you're doing is talking to a source code control system), then adding bandwidth won't make a bit of difference. It would be like using a box truck to pick up a your groceries.

For the kinds of usage patterns that source code control systems generate, latency is most likely going to make a bigger difference.

The classic example is the old saying, "Never under-estimate the bandwidth of a van full of tapes." It's true - the bandwidth of such a system would be incredible compared to what most people are used to working with. It's just that the latency for, say, a connection between Inda and the UK would be measured in days.

Re:Measure twice, cut once

[kclittle]

Is that a laden or unladen ray of light?

Re:Measure twice, cut once

[shigelojoe]

It would be like using a box truck to pick up a your groceries.

The internet is not a big truck! It's a series of tubes!

Also

[Surt]

Dear slashdot:

I'm trying to outsource your jobs. However, I don't know all that I need to know. Would you mind providing free training in your spare time for your replacement?

OTOH: you probably don't need as much speed as you do reliability. I would guess that an unsharing situation will work better for you.

You might, over the short term, insert an extra hop in your network in front of the ISP hop, and measure avg bandwidth there over the course of a business day. As long as you have enough total bandwidth / second to match your typical usage (allowing for some margin, and expected growth) in a business day, all you'll cope with is some latency.

Seems silly to me.

[onion2k]

Unless there are also developers in the UK constantly accessing the code repository there's no good reason to use source control outside of your office. It'll be considerably cheaper to buy a small server with a RAID array, stick Subversion on it, and put it on your network, than it would be to be transfering files all the time. If the company in the UK that you work for insist on having control of the code then write something that syncs diffs between your local repository and the UK nightly/a few times a day/hourly/whatever. 13 coders aren't likely to be checking in more than a couple of megabytes of changes every hour.

Note: SVN/CVS/SourceSafe/whatever can probably do this already, IANAEIVS (I am not an expert in versioning systems).

Subversion.....

[Anonymous Coward]

One thing you could look at is to use subversion as your source control system, as it only transfers diffs accrss the network so is very good with low bandwidth connections.

I have karma to burn...

[Yonder Way]

...so I will just say what half the other people here are thinking.

Maybe you can outsource this project to the west since there are plenty of very well experienced people who know this stuff who could use the work.

I don't hate India or Indians, but it will be a cold day in Hades before I give assistance to a shop whose only purpose in this world is to displace jobs formerly occupied by my neighbors.

Re:I have karma to burn...

[Anonymous Coward]

Perhaps we can get together some day and discuss this while we take a ride to Walmart in your Lexus.

Seriously, I'm not convinced by the economists that our current import/export situation is a good thing, and I've always been a big Buy American advocate, but I find intense irony in the fact that my IT coworkers seem to all think I'm retarded for buying a Ford, but can go on endlessly about outsourcing programming to India.

I don't know Yonder Way, and maybe this doesn't describe him, but I've always been amazed at the hypocrisy on this topic, and the smug condescension toward displaced factory workers and such.

And one more thing: I don't fault the Indians for going to work at these jobs. I would certainly do it if I were in their shoes. I fault the American citizens for their purchasing and voting decisions.

Re:I have karma to burn...

[Badfysh]

Since you're not being very helpful, I'll give the guy a hand. Fortunately, I have a lot of time on my hands now that I'm unemployed here in the UK and...

Actually, forget that.

Re:I have karma to burn...

[sumdumass]

What gives then that "right" is more of an issue of fair play.

You see, his neighbor (in this implied situation) didn't lose his job because he done something wrong, he didn't lose it because some one better came along and could do it more efficiently. He didn't lose it because some produced a product cheaper from a better process. He lost it because some one is exploiting the difference in the econemy between two places.

If the dollar was the same value everywere and a gallon of milk cost the same in india, china, UK or USA, then the job would never have left the country. But the reality is that we are exploiting third world countries and lessor developed countries because they are lacking the development of econemy that the rest of the world has. We are seeing people working for pennies on the dollar mostly because when converting the penny to the other currency, it is valued more like a dollar.

Now, the right that is implied is were a company wishes to compete in one location but derive it's labor supply another. We aren't importing the product, just the labor for the product. In the real world, minimum wage laws, unions and trade contracts would place limits on the lowest a company can pay the employee but when outsourcing to other countries, they are getting around this. Imagine the government allowing mexicans to come to america legaly with the intended purpose of working for less then minimum wage at factories were normal workers get $12.00 per hour. It would never last (on a legal basis) but outsourcing is basicly allowing this to happen.

It might not exactly be a right to work more then a obligation for the company to hire employees in the country that they are set up in and doing business in. If the company wants to set up shop in that arbitary geographical location then let them hire all they want from there. Fireing some one in the location were you make your product, profits and public image in order to exploit the difference in currency or econemy in another location doesn't seem proper. If you think it's ok to screw the people over in the area making the bread and butter for your company then more power to ya. I'll save you a spot in the unemployment line when you find out your job has been replaced by someone doing it for 40 cents an hour because the working conditions and monetary value of the currency in some other country is so different. At least japan decided to make plants in america when the foreign cars cost so much less then american cars because the value of the yen.

Quick thing on sharing

[QuantumRiff]

Will I get a better bandwidth if I take a 512 leased line on 1:2 sharing?

Yes and No. Right now you are setup on a 512K/s line, shared with up to 4 other customers. This means that if Customer A is using 400k/s, and Customer C is using 100k/s, then customers b and c get to share 12k/s. (without getting into the discussion of prioritizing and QOS, I'm way oversimplifying) Or, depending on the setup, each of you might be setup to only get 128k/s when all of you are using your connection. Now, if its the first case, and you have one other customer that is hogging all your traffic, then you will benifit from moving to a 1:2, or even just getting rid of them on the same circuit. However, the only way to be sure that you have 512k/s if you need it is to make sure you have your own connection, and a garuntee from the ISP. (in the US, these are called "Business class" DSL circuits in many areas) It will be MUCH more expensive.

Pony up and pay

[TLouden]

You say you can't afford to figure this out with an expert. My response is that you're asking your competition to help you cut your costs so that you can better compete with them.
Enjoy the answers.

When you could have asked....

[russ1337]

You could have figured out how much bandwidth you don't have by posting a link to your local server. Being Slashdotted would've shown your ISP you need more bandwith!

Then; Take the number of connections at your end before your connection was severed, and add that to 'half' the number of connections when your ISP's server/connection maxed out, multiply by the number of toilets in your office, and divide by Pi.

Pricing

[solid_liq]

"(There's a huge price gap between the 2 here in India) In any case, how does one decide the optimum bandwidth required for a bunch of 15 developers on VPN and Source control?"

Welcome to the world of business. Are you starting to understand why we charge as much as we do outside of India? It's because we have to support our business infrastructure and still make a profit for all our effort! Don't like it, go back to India. Oh wait...

Tell

[mattboston]

your developers to stop downloading porn and illegal music at work.

Re:Me too (re: I have karma to burn...)

[hab136]

The good news is that the dollar crash will take out the families with "old money" too, and we can return to a more egalitarian economic system. It'll be rough, for a bit, but definitely worth it.

Nope. Old money families usually own resources, not dollars. If you own a diamond mine worth $3 million today, and the dollar deflates by 100 - now you own a $300 million diamond mine. You've lost nothing. Same with stock, pork futures, or real estate.

The rich usually stay rich.

However, your $70k mortgage balance is still only $70k, while the value of the house is now $7 million. Any debt you (or rich people) hold would become trivial to pay off.