Round robin for internet?

[ivwshane]

I know there is the ability to do a round robin on an internal network (anandtech does it) but is it possible to do it on from the outside? For example, let's say I have three friends who all have a small amount of bandwidth and webspace. Individually they can't host alot but with all three of them they can support a decent amount of clients. I would imagine that one system would be the main system and that one would be where the domain resolves to but then it would some how look at the other three servers (again they aren't on a local network) and probe them to see what their load is and depending on the load the client would be auto redirected to the server with the least activity.

This sounds like it would be accomplished by some script but I want to know if there is an easier way or if this has already been done. Also I would like this process to be transparent to the user.







I hope that made sense.

 

[PurdueTech]

I am prety sure you usually setup round robin in the name server setup. You specify multiple ip addresses for the same site and the dns server (usually) will split the load equally between the addresses.

http://http://www.webopedia.com/TERM/R/Round_Robin_DNS.htmlLook Here

Anyone understand round robin any better? I am almost certain that is correct.

 

[ivwshane]

I know, but isn't that assuming that your clients are connecting to your DNS server? So if some person types in your url he uses his ISP's DNS server who then points to only one IP registered to the domain?

I understand it when it's used internally, meaning that all servers are on one internal network but how would it be done if say, one person had one server on his home system with SBC, and the other was with comcast, and the third is with verizon.

 

[AFB]

No, I think it changes when ever it looks it up.

 

[MysticLlama]

Round robin works the same way internally or externally.

All you do it assign multiple IPs to a particular domain name.

The process would go like this.
foo.com is registered through whatever registrar
Client does a lookup to the registrar and finds out that ns1.bar.net and ns2.bar.net are the nameservers
In those nameservers (your ISPs, or your own if you have nameservers) that you want it to be on 10.0.0.1, 10.250.32.8, and 10.81.13.42 (whatever real numbers your friends have)
The nameservers then just give them out in order when a client does a lookup on them, thus splitting the load.

This doesn't take into account client-side or proxy caching, and it doesn't know if a host is down or not.

So someone may hit the same host over and over because their machine or their corporate proxy cached the IP, and they may just get a blank page if they hit one of the IPs that happens to be down.

 

[ivwshane]

I guess I need to get familar with name servers.

So the problem of caching arises and the possibility of a host being down can affect service as well, so what would a more ideal alternative be within the given setup?