[vox-tech] two networks, one app

[Bill Broadley]

Peter Jay Salzman wrote:
> Hi all,
> 
> Is it possible to transparently get network connectivity from two network
> interfaces, say eth1 and wlan1, at the same time?  I guess which one is used
> depends on which one is busy at any given moment.

Fast, easy, and always works no.  Did you have a particular use in mind?

> Suppose I had two working interfaces -- how would such a thing be
> accomplished?
> 
> If it can't, is there any way to leverage two network connections to make my
> apparent connection to the internet faster?

Bittorrent would be easy, run one copy per uplink, then use various lan
disovery or manual peer injection to tell them about each other.

Now without setting up a routing infrastructure which requires cooperation at
someone on the internet side of your conenction for routing or bonding your
only other choice is to use something of a kludge.  The main problem being
that a TCPIP connection has a session, and that session is expected to come
from the same IP.  So if you say ssh somewhere for the duration of that
connection you are going to have to that uplink for the ssh connection.

So basically a router could round robin or based on load send new TCP
connections to the less utilized link. That doesn't prevent 2 TCP sessions
from heavily competing with each other while the other link is idle.

One particular usage that is friendly to this kind of thing is HTTP.
Typically TCP connections your browser opens are very short.  So an hour
surfing the internet uses many many connections not one.  Use wireshark to be
sure though.  Unfortunately many session ID widgets will put your IP in a
cookie (or it's hash), which will cause problems for more than one IP.

I believe I've seen HTTP proxies for just such a thing, providing privacy,
agent hiding, multiple uplinks, even the option to put certain kinds of
traffic through another transport like tor.  Alas I don't recall the name.

So in short, nothing easy, except maybe for torrents.